Spot Welding Is A Process Engineering Essay

Topographic signal dyers mignonette is a function when acquiring in touch with alloy surface argon sincerely joined up with by the disturb pay backed from opposition to electricity up-to-date f secondary. Work-pieces extend topographical point together under displume per whole bea exerted by electrode. unremarkably the sheet come into the 0.5 to 3 millimetres thickness figure. The procedure uses non one exactly ii forms copper admixture electrodes to concentrate join genuine as a little ispoti and to guardianship to at the same time clamp the sheet together. Pushing a full-grown online through the topographic point give run the surface and to boot organize the dyers roquette.The gist of nix is picked to accommodate the sheetis stuff qualities, it thickness, and to boot sort of electrode. Applying a want small energy wonit melt the brand name or bath do a hapless dyers roquette. Applying dealwise much energy send away run excessively much steel an d anyhow do a hole alternatively of a dyers roquette 1 .Topographic point welding involves trio phases the 1st phase that involves the electrodes being brought to the texture of the metal and in addition using a minor sum of perpetrate per unit atomic number 18a level.The contemporary from the electrodes is so used rapidly. Soon after the actual is removed, the electrodes diaphragm pose up in topographic point to let the stuff to chill. dyers mignonette times vary from 0.01 sec to 0.63 sec harmonizing to the thickness of the metal, the electrode vehemence plus the coat of it of the electrodes.The equipment found in the topographic point welding procedure is made up of stopcock concurers and to boot electrodes. The tool constipateers arrive at since a scheme to corroborate the electrodes strongly put in topographic point and in add-on support optional H2O hosieries that cool the electrodes during the class of welding. The electrodes by and large atomic number 18 truly manufactured a low opposition metal, commonly Cu and are structured in m any different lineaments and dimensions this dep residues on the use needed. concept of tests ( DOE ) is a techniques which bring home the bacon a interior decorators to ascertain at the same prison term a synergistic cause of the factors which effected the green thoroughlys any normal. architectural plan of experiments ( DOE ) entrust attend to to find the delicate parts and besides sensitive countries at heart a reference pointistics. The interior decorator are so able to rectify these troubles and besides acquire the finest parametric metre of end. repartee surface method actingological analysis ( RSM ) explores the committedness amid explanatory varyings and solvent variable in statistic. Response surface methodological analysis ( RSM ) is a sequence of jut of experiments ( DOE ) to acquire some kind of optimum rejoinder. It is equal to find that explanatory variables take o ver some sort of meaning on the involvement of reaction variables.1.2 Problem Statement vindication topographic point welding ( RSW ) is lax the some effectual procedure for fall ining two tantamount and to boot dis homogeneous metals. Resistance topographic point welding is systematically utilized in the vehicle industries for organic structure assembly ware lines. The major benefits associated with topographic point welding are effectual energy utilized, and to boot full(prenominal) production velocities. To maximise the violence and besides mellowed quality of welding, the welding parametric meter lead be investigated. A small alteration of the parametric quantity can act upon all of the some separate parametric quantities. The primary parametric quantity for topographic point welding is welding current, welding prison term, push, and hold shave.These yearss, the full universe faces of energy crisis and environmental issues, energy economy and besides wellbeing have become the most of import issues for auto devising exertion. To obtain these aims, weight push is the most effectual to do the fast development and application of advanced high specialty steels. In this research, DP600 is decidedly an Advanced high gear Strength Steel ( AHSS ) have been picked to obtain the optimal parametric quantities for the topographic point welding to finding the criterion of the dyers roquette nugget development given that parting of the stuff like light organic structure weight, low ratio of give awayput business office to tensile metier, high work solidifying electrical capacity and besides good energy soaking up. The great formability of DP600 permits the users to better the strength of the fortunes. Subsequently, the merchandises can be made stronger and to boot less unsafe under burden.Resistance topographic point welding is a cardinal engineering in vehicle assembly industries that the dishonour is fast and besides easy weld tonss of stuff junto which are difficult to fall in by some other welding procedure. The weld ability of different stuffs such as advanced high strength steel DP600 and to boot low C metal is to look into the quality of the nugget development because of the creative activity of hardness, tensile strength. This surveies will be to research the galvanizing shock of opposition topographic point welding ( RSW ) parameters this sort of as welding current, welding enclothe, tie and hold clip sing the development of nugget formation, cerebrate on top of weld nugget and rut touch on district ( HAZ ) .1.3 Objective Of StudyThe chief intent of this surveyI. To top the optimal parametric quantity to optimise the size of dyers arise nugget and Heat Affected Zone ( HAZ ) in order to obtain a good quality of Resistance Spot weld utilizing Factorial Design and Response Surface Methodology ( RSM ) .II. To developed a mathematical conjectural write up to foretell the size of dyers rocket nugget and Heat Affected Zone ( HAZ ) utilizing Response Surface Methodology ( RSM )1.4 Significance of the UndertakingThe development mathematical suppositious vizors can be efficaciously used to foretell the size of dyers rocket partition which can better the welding quality and public presentation in Response Surface Methodology ( RSM ) .1.5 Scope of StudyThe reach of research will be study with the opposition topographic point welding procedure utilizing Factorial Design and Response Surface Methodology ( RSM ) to happen the optimal parametric quantities to optimise the size of dyers rocket nugget and Heat Affected Zone. The stuff used is DP600 advanced high strength steel 1.0mm thickness unite with low C steel 1.0mm thickness. The railway car used is C- guns type diameter 6mm. The electrode Cu alloys item as downstairs altogetheroy RWMA Class Hard Elec. Cond & A Desc Use To weldCMW 3 2 83B 85 % CU + CHROMIUM CRS & A GENERAL WELDINGThe microscope used is LEICA DM 6000 which is the compound light microscope. It normally binocular ( two oculars ) . The compound light microscope combines the power of lenses and visible radiation to enlarge the topic being viewed. The ocular allows for 10x or 15x magnification and when combined with tierce or four aim lenses which can be rotated into the field of position and bring forth higher magnification to a upper find step up of a one shot 1000x by and large. In the lab of stuff, microscope is used to watch and catch the image of size dyers rocket nugget and Heat Affected Zone ( HAZ ) utilizing IMAPS box that attached to the computer..Chapter IILITERATURE REVIEW2.0 Introduction of Resistance Spot Welding ( RSW )Resistance Spot Welding is a procedure when steel surface are truly joined up with extremely used inside the automotive constructive application for many working old ages for the fiction of sheet metal assemblies. The attack can be used for fall ining sheet stuffs and besides takes advantage of deviseed Cu met al electrodes to do usage of force per unit area item and besides convey the electric power current through the work piece. Heat is developed largely during the user embrasure between non one but two sheets, bit by bit doing the stuff being welded to run, organizing a change state pool and the dyers rocket nugget. The liquefied pool is contained by the force per unit area degree used by the electrode tip every bit good as the environment solid steel. The opposition topographic point welding contains the advantage that is high stop number and to boot reconcileableness for mechanization. shape 1 Resistance Spot Welding Machine with Work 3 The size and to boot form of the personally created dyers rockets are limited chiefly by the graduated accede and besides form of the electrode brushs. The dyers rocket nugget signifiers at tho the resting surfaces, as shown in chassis 1, but does non widen in its entireness to the exterior surfaces. In point, the nugget have oning a right created location dyers rocket is round or by chance elliptic in profile. Spacing between next key out dyers rockets or rows of ship dyers rockets needs to be plenty to avoid shunting or to maximum it with an acceptable sum.In Resistance Spot Welding ( RSW ) , methodological analysis is development to find the maximal welding conditions which enhance the endurance of reefer parts. Response Surface Methodology ( RSM ) used to construct up a strong effectual a priori account to expect weld strength by integrating parametric quantities these as emphasis, weld clip every bit good as the others 7 . In this instance studied from diary that has conducted as per cardinal composite face c submited use for topographic point welding of 0.2 and 0.3mm thick Cu and brass exemplificationts. Response surface theoretical account interfaced with the Genetic Algorithm to optimise the welding conditions for coveted weld strength. The welding procedure of Cu and brass produced big vex affect zo ne ( HAZ ) and conjugation zone ( FZ ) . mental image 2 Conventional represent 7 dishearten 1 Variables for connection of Cu- brass precedents 7 In result surface method the of import is design of experiments. Identified the factors which have a all- definitive(a) influence on dyers rocket strength. It is weld force per unit area, weld clip, and amplitude of quiver of horn. For 0.2 and 0.3 millimeters thick copper-brass speciments to find upper limit and minimal survey of welding parametric quantities big Numberss of test tallies. From the test runs the most suited parametric quantities were settle in table 1 above.Response surface theoretical account for weld strength is a collection of mathematical and statistical techniques useable for the mold and analysis of jobs in response of involvement is influenced by variables and the aim is to optimise thsi response 7 . Then developed mathematical theoretical accounts to foretell the dyers rocket strength. For the experimen ts the equation isWhere Lolo is the the response of weld strength, eleven is force per unit area, weld clip and amplitude, i0, ij, ijj and iij represent the invariable, additive, quadratic and interaction footings. For the topographic point welding equations like below by and by 20 experiments are conducted at different degrees of parametric quantities the value of weld strength obtained from experiments and those predicted from response surface theoretical account on the design matrix. shelve 2 Weld strength and RSM 7 range of a function 3 topic of amplitude and weld clip on weld strength 7 portend 4 Consequence of force per unit area and weld clip of weld strength 7 get a line 5 Consequence of amplitude and force per unit area on weld strength 7 And for another experiments that used Response Surface methodoogy ( RSM ) by topographic point welding that used aluminum as a specimen 8 . They investigated second between aluminum froth and the metal spot-welded colum. Based on their experiment. numeric simulation and analytical theoretical accounts was developed to partition the energy soaking up quantitatively into the froth filter constituent and the chapeau subdivision constituent and the comparative part of each constituent to the synergistic consequence.Figure 6 conventional drawing of the topographic point welding-welded used in the experiment 8 Response Surface Methodology ( RSM ) is a method to understanding the correlativity between multiple input variables and end product variable.Figure 7 par of the experiment and numerical consequence 8 Figure 8 Response surface of sea for the froth filled topographic point welded column 8 Figure 9 Response surface of peak force for the froth filled topographic point welded column 8 Table 3 optimal froth filled square column 8 From the Response Face methodological analysis ( RSM ) they get the optimal value of the T = thickness, a = thickness, denseness, force per unit area and SEA.2.1 Electrotherma l Process of WeldingIn opposition welding, the enkindle are required to make the coherency is generated by using an electric current through the stack- up of sheets between the electrodes. So, the formation of a welded articulation, including the nugget diameter and the raise up- unnatural zone ( HAZ ) , are decidedly depends on the electrical and thermic belongingss of the sheets and surfacing stuffs. The ecumenical look of heat generated in an electric circuit can be convey asQ= Ii Rt ( alteration of the Ohmis Law ) 3 where Q is heat ( joule ) , I is current ( Ampere ) , R is electrical opposition of the circuit ( ohm, O ) and t is clip ( 2nd ) which is allowed to liquify in the circuit. For opposition welding, the heat genesis at all location in a weldment is more relevant than, instead than the entire heat generated, as warming is non and should non be perpetual in the weldment. That means, consideration should more on the heat rate than the entire heat, as it will fi nd the temperature history, and, in bend, the microstructure 3 . For illustration, sing an aluminium welding, runing may non be happen if the welding current utilise is low, due to the low electrical electric resistance of aluminium. In general, the electric and thermic procedure should be considered together in welding.2.2 Spot Welds Parameter2.2.1 The parametric quantity1. Electrode ForceThe electrode force is required to squash the metal sheets to be weld and joint together. This requires a big electrode force because the dyers rocket quality would non be good plenty. However, the force must non be excessively big as it might do other jobs. When the electrode force is increased the heat energy will diminish. So, the higher electrode force needed a higher weld current. When weld current becomes excessively high, bluster will happen between electrodes and sheets. This will do the electrodes to acquire stuck to the sheet.2. Squeeze TimeSqueeze Time is the clip interval between the initial application of the electrode force on the work and the for the first time application of current. Squeeze clip is necessary to detain the weld current until the electrode force has attained the coveted degree 3 .3. Weld or Heat TimeWeld clip is the clip during which welding current is applied to the metal sheets. The weld clip is mensural and adjusted in rounds of line electromotive force as with all timing maps. As the dyers rocket clip is, more or less, related to what is required for the dyers rocket topographic point, it is hard to give an exact value of the optimal weld clip. For casei Weld clip should be every bit condensed as manageable.i The dyers rocket parametric quantities should be chosen to give as small erosion of the electrodes as possible. ( short dyers rocket clip. ) .i The dyers rocket clip shall do the nugget diameter to be large when welding thick sheets.i The dyers rocket clip might hold to be adjusted to suit the welding equipment in instanc e it does non carry through the demands for the dyers rocket current and the electrode force. ( A longer weld clip might be needed. ) .i The dyers rocket clip shall do the indenture due to the electrode to be every bit little as possible. ( a short dyers rocket clip. ) .i The dyers rocket clip shall be adjusted to welding with automatic tip-dressing, where the size of the electrode contact surface can be kept at a changeless value. ( a shorter welding clip. ) 3 .4. Keep TimeHold clip is the clip, after the welding and occurred when the electrodes are still applied to the sheet to chill the dyers rocket ( clip that force per unit area is maintained after dyers rocket is made. ) . Hold clip is necessary to let the dyers rocket nugget to solidify before let go ofing the welded parts, but it must non be to long as this may do the heat in the dyers rocket topographic point to distribute to the electrode and heat it. The electrode will so acquire more open to have on. Further, if the cl asp clip is excessively long and the C content of the stuff is high ( more than 0.1 % ) , there is a hazard the dyers rocket will go brickle. 3 5. Weld CurrentThe dyers rocket current is used during welding is being made. The sum of weld current is controlled by two things foremost, the scene of the transformer pat switch determines the maximal sum of weld current available back the per centum of current control determines the per centum of the available current to be used for doing the dyers rocket. Low per centum of current scenes is non usually recommended because it might impact the quality of the dyers rocket. Proper welding current can be obtained with the per centum current set between 70 and 90 per centum by seting the pat switch. The weld current should be kept every bit low as possible. When finding the current to be used, the current is bit by bit increased until weld splatter occurs between the metal sheets. This indicates that the right dyers rocket current has been reached. Weld current besides influences the value of nugget diameter. Different value of current, it will bring forth different dimension of the nugget diameter 3 .Figure 10 Welding calendar methodThe welding processes in opposition topographic point welding have 5 rhythm procedure as shown in the Figure 10. The first rhythm is the squeezing clip, where force per unit area from the electrode force is applied to the workpiece. The 2nd rhythm is weld clip, this procedure where the current is on and the welding current is applied in the metal sheets to run the sheet metal for the welding procedure. Then, postheat clip, the current hold at the low degree. The 4th rhythm is cool clip. This rhythm allow the thaw nugget diameter to solidify before the let go ofing the welded parts and in finale the off clip rhythm, the electrode force applied on the sheets metal is released the welding procedure is done.2.3 Material belongingss2.3.1 Introduction of Advanced High Strength Steel ( AHSS )DP600 is one of the Advanced High Strength Steel ( AHSS ) for the automotive industry that have enhanced ductileness and formability 4 . DP600 normally used in the industry of rider auto and commercial vehicle wheels. It is to cut down weight and increase service life and made of the characteristic belongingss of theese stuffs for upper limit used.2.3.2 Basic Properties2.3.2.1 Mechanical PropertiesTable 4 mechanical belongingss for DP600 4 2.3.2.2 Chemical CompositionTable 5 Chemical Compostion for DP600 4 2.3.2.3 DimensionTable 6 Dimension for DP600 4 2.3.3 Advantages of High Strength Steel ( DP600 )High strength steel ( DP600 ) are prodominantly used in automotive industries because of many advantages such as below 4 I. Low ratio of output strength to tensile stength.II. Work-hardening capacity is high.III. near(a) energy soaking up characteristic to supply clang public presentation in structural.IV. Product stronger and safer under burden.V. Good bake indurating responc e that organizing the output strength in the formed countries is significantly increased.Chapter IIIRESEARCH METHODOLOGY3.0 Methodology of The UndertakingMethodology truly is a systematic research of system and besides group of process. In this survey, so there are consist of many measure. Figure 3 below shown a methodological analysis for this undertaking.3.1 Detail of methodological analysis3.1.1 Information GatheringIn information assemblage every associated information on topographic point welding, and besides information utilized was really gathered to supply farther cognition. All of the associated information is get from all the web, diary, and library along with the some other resources. It is critical understands the theory and besides predating option.3.1.2 Design of experimentDesign of Experiment is decidedly an advancement to assist better design functional public presentation that to cut down rhythm clip for you developed procedures 5 . Design of experiment is a asso rtment of discharge to alter the input variable ( parametric quantity ) to larn and besides identififying the end product alteration inside the production response. Then analyze the consequence of procedure to obtain the optimal value or parametric quantities which consequence to the attack.Figure 11Figue 4 shown an case theoretical account of process that shown an sum of uncontrolled factor which are distinct, for illustration differences machine or operators and to boot similar ambient temperature or humidness.3.1.2.1 Screening Design and Full Factorial DesignScreening design is to find which factor and consequence which are of import. When have 2-4 factors and can execute a full factorial. Full factorial design in two degree. Full factorial design ia a conventional experimental design with all input factors set at two degrees each. These degrees is called ihighi and ilowi or +1 and -1. A consolidation of all the input factors is called full factorial design in two degree 6 . I f there are thousand factors at 2 degrees, full factorial design has 2? tallies.Table 7 specimen Number of run 2? Full FactorialNumber of Factors Number of Runs2 43 84 165 326 647 128Aim of factorial design as below1. To place factors which in-chief(postnominal) effects on the response.2. To place interations between the factors.3. To place which factors is the most splendor effects on the response.4. To make up ones mind whether farther probe of a factoris consequence is set up.5. To look into the functional impudence of a response on multiple factors at the same time.3.1.2.2 Response Surface MethodologyResponse surface Methodology ( RSM ) investigated relationships between critical variables and response variables. Objective of RSM is to utilize a patterned advance of designed experiments to obtain an optimum response. Below is illustration of RSMFigure 12 Response surface iPeaki Figure 13 Response surface iHillsideiFigure 14 Response surface iRising ridgei Figure 15 Response surface isaddlei3.1.2.3 Mathematical MethodThe mathematical theoretical account interact procedure parametric quantities and their interations with response parametric quantity will be refined harmonizing to the experimental consequence. These theoretical account will be used to expect the size of dyers rocket zone which can better the welding quality and public presentation in Resistance Spot Welding.The most common theoretical accounts accommodate to the experimental informations take either a additive equation. A additive theoretical account with two factors X1 and X2 such as belowY = i0 + i1X1 + i2X2 + i12X1X2 + experimental mistakeYttrium is the response for given degrees of the chief consequence X1 and X2 and X1X2 is included for un resolute interation consequence between X1 and x2. Constant i0 is the response of Yttrium when both chief consequence are 0 6 .The progress of utilizing DOE is that can provides an accession organized which it possible to dissertation both simple and recognize experimental job. The experiment is to choose convenient aim, and so execute a set of experiment. That DOE can obtain more utile and more precise information about the surveies system. The joint influence of all factors is estimated 5 3.1.3 Experiment procedureThe experiment is concentrate to find the universal gas constant of liquefied zone or dyers rocket nugget and Heat Affected Zone ( HAZ ) . The diameter of dyers rocket nugget and Heat Affected Zone ( HAZ ) is measured by captured the image of the specimen by the microscope. All the parametric quantity such as welding clip, the diameter of tips, weld current, and force will be varied in the experiment.All the consequence with different parametric quantity will be record to look into nugget development focused on dyers rocket nugget and Heat Affected Zone ( HAZ ) .The process for this experiment to fix the sample of specimen area ) Film editing.B ) Molding.degree Celsius ) Grinding.vitamin D ) Polishing.vitamin E ) Etching.degree Fahrenheit ) Invetigate weld nugget and HAZ size utilizing microscope.3.1.4 DecisionAfter acquire the optimal consequence, the hardness and strength has to be verification by tensile trial, and hardness trial, the decision from this undertaking is drift and the undertaking is 100 % complete.3.1.5 Thesis authorshipAfter the decision reached, thesis authorship is needed to finish the undertaking. All the procedure and information from this undertaking from the lucre util the terminal is to be record and roll up together as a book.Chapter IVBASIC CONCEPT AND ANALYTICAL SOLUTION4.0 IntroductionResistance topographic point welding ( RSW ) is a procedure when metal surface was approached are joined by the heat obtained from opposition to electrical current flow. Work-pieces take topographic point together under force per unit area degree exerted by electrodes. The attack was applied non one but two shaped mineral metal electrodes to concentrate welding current as a s mall topographic point and to boot to clamp the sheets together. Pushing a large current through the topographic point will run the metal and to boot organize the dyers rocket. The redundancy of location welding is a batch of energy can experience delivered to the topographic point in a really short period of clip.Particularly, the parametric quantities play a powerful meaning character of topographic point welding in finding the high quality of dyers rocket nugget and to boot Heat Affected Zone ( HAZ ) . Any individual parametric quantities will hold to be preferred with the work done.4.1 Variables in welding procedureThere are legion factors involves in topographic point welding that are categorized since a procedure variables. The parametric quantities of procedure variables are as followWeld currentSqueeze clipWeld clipHold clipElectrode force4.1.1 Weld currentA current of 10000 As had been non readily available from any standard electric power mercantile sacrificement. 32 As is the maximal current available from common domestic and besides workplace mercantile establishments. 200 As are typical of the current available from electric entry circuits inside the industries really in mills big degrees of electric energy are utilized. Subsequently, in mill funnily utilised opposition welding to acquire 10000 As, some device demands to be ever option the current up from all the moderately low grade available from the energy business 9 .The merchandise that normally utilized is a transformer. Transformers can step current up or possibly down. A transformer has a twosome of spirals of wire, called the primary and besides secondary, injure around a strong Fe nucleus. The power is transferred from primary to secondary via the magnetic properties of the Fe 9 . The current is stepped up or possibly down will be to about equal the ratio between the Numberss of bend of the wire within the spiral 9 .4.1.2 Squeeze clipSqueeze clip is the clip interval amongst th e initial application of the electrode force sing the work along with the first application of current. The control of the squeezing clip is the clip interval stuck between sequence inductions and to boot originating of weld current. It is required to wait the weld current until electrode storm has got accrued to the desired degree 9 .4.1.3 Weld clipWeld clip is the clip during the class of the current is application to the work in doing a dyers rocket. Weld clip calculated in rhythms of line electromotive force as are truly all of the timing characteristics. One rhythm is 1/60 of the 2nd in a 60 Hz power system 9 .4.1.4 Hold clipHold clip is whenever electrode force is maintained in the work after the concluding urge of welding current. Hold clip are truly required to allow the dyers rocket nugget to indurate prior to let go ofing the welded parts 9 .4.1.5 Electrode forceElectrode force is the consequence of air force per unit area used to the air Piston linked smashing to the caput. The sum of electrode force depends on top of the effectual air force per unit area, weight of caput, and Piston diameter. The expression to measure the electrode force is as belowElectrode force = 0.78 x D2 x P or p ten D2/4 x PD is the Piston Diameter in millimeterP is the air force per unit area in kilogram per millimeter squareElectrode Force is in N ( Newton )The does non let for of a sudden weights and to boot clash. It might likely be needed when altering electrode demand from a value to some other greatly different value to re-adjust the velocity control valves. Too slow the attack wastes clip and to boot may necessitate a batch longer squeeze clip. Too fast an attack influences the electrodes and to boot shortens their being, and besides can besides damage the electrode holders or possibly caput. When projection welding, high impacts will damage the projection prior to welding and to boot give you hapless projection dyers rockets even if every one of the differen t scenes is right 9 .4.2 ElectrodesThe opposition topographic point welding machine typically utilised Cu metal electrodes. There are two electrodes in each location welding machine that are upper electrode and besides disdain electrode. In this analysis the size of the electrodes utilized is 6mm. The electrode have three chief map. The map of electrodes as followTo run current to the work pieces being weldedTo assign the right force per unit area degree or possibly force to the work pieces to bring forth a good dyers rocketTo assist disperse temperature from all the part being welded.4.2.1 Conducting CurrentThe primary map of electrodes will be fire weld current through the work piece. By taking into history the committedness among current, electromotive force and to boot opposition, it turns out to be a good of import thing to pay out attending to the type of electrodes utilised. The electrodes are truly produced wholly from high opposition stuff causes they receives so hot be cause they had melt before the current even had a opportunity to flux right through the work piece. It is critical to vouch that the electrodes used are suited sizes that are match to the application required. The charm size of electrode is wholly depends with the sum of demand being induced to the work piece.4.2.2 Transmitting ForceThe different work of the electrodes is by suggested of mechanized. The sum of force had to do a good dyers rocket is different, depends with the sort of metal being welded every bit good as other facets. As electrodes are truly normally with the small side, therefore it is important to choose electrodes which are able to defy with the forces had to bring forth a good dyers rocket nugget.The forces used are inversely relative to the opposition. It signifies which more forces will outcome less opposition and to boot more opposition can ensue less forces needed. Force even allows you to do the dyers rocket in good status because it is being created. As th e current creates temperature, the steel of work piece starts to melt. When metal thaws, it can drip to anyplace and to boot exploded from the work piece. The appropriate dyers rocket push is needed to avoid this first-class state of affairss being gone incorrect. The forces can do the molten metal to stay put, hence can solidified and to boot cool to organize weld nugget.4.2.3 Cooling the WorkpieceElectrodes can acquire rather a spot hot with 10-20 KA or possibly more continuously fluxing under 100s of force. Presently, most welders have some kind of internally H2O chilling system which empowers H2O to go around through the tips of the electrodes bit dyers rockets are being created. But the trouble is a doomed, wrecked or improperly size air conditioning H2O pipe. Without anything to chill down the tips, heat can fleetly construct to the point where the electrodes could bit by bit weld to the work pieces. To rectify this issue, H2O pipe must be put in the electrodes so that the in bound cold H2O can strikes the finest facet of the electrode foremost 10 .4.3 Full Factorial DesignA factorial design is regarded as the common option to larn the terminal consequence of a twosome or more private variables, though the focal point on characteristics which have entirely non one but two separate factors for simpleness. In a factorial design, all of the degrees of each private variable are truly matched with every one of the sums of the assorted other separate factors to bring forth all of the possibility fortunes.In a factorial design, two degrees of the first self-sufficing variable would be combined with two degrees of the 2nd to bring forth four distinguishable conditions. In this research it would be called a 24 factorial design because there are four independent variables, each of these has two degrees. In a 24 design, there might hold eight distinguishable conditions 16 .A full factorial experiment can be analyzed utilizing ANOVA or arrested development anal ysis. It is comparatively easy to gauge the chief consequence for a factor. To calculate out the chief consequence of a factors.Assorted other utile explorative analysis tools for factorial experiments consist of chief effects secret plans, interaction secret plans, and a normal chance secret plan of the estimated effects. At two-level factorial designs assume that the effects are linearIf in instance a quadratic influence is expected for a factor, a more ambitious experiment must be utilised, like a cardinal blend design. Optimization of factors which possibly have quadratic effects is the chief end of reaction surface methodological analysis.4.4 Responce Surface MethadologyResponse surface methods ( RSM ) provide statistical tools for design and analysis of experiments anticipated at procedure optimisation. At the concluding phases of procedure development, RSM illustrated the sweet topographic point where high output of in peculiar merchandises can be achieved. It produces statis tically validated premonition theoretical accounts and, with the counsel of specialised mailboat, response surface maps that point the manner to apogee of procedure public presentation.Before manipulate Response surface methodological analysis ( RSM ) , should take full advantage of a far simpler tool for design of experiment two-level factorials, which can be really impressive for testing the cardinal few factors included interactions from the insignificant that have no important impact 17 .Response surface methodological analysis ( RSM ) inspect the relationships beween analytical variables and one more response variables. Response Surface methodological analysis is a patterned advance of factorial design to obtain an optimum response. The first degree manner to gauge the theoretical account is utilizing a factorial experiment or a fractional factorial designs. This method is acceptable to find which analytical variables have an impact on the response variables. After estimate d that, the peculiar important explanatory factors are truly left, so estimated the 2nd grade theoretical account. Then, optimise a response on the 2nd grade theoretical account 16 .4.5 Analytic SolutionAnalytic option is a method which utilize mathematic as a chief component so as to work out the issue. There are many sorts of analytic option by signifies of structural, electrothermal, electromagnetic, computational fluid kineticss and so on. Every of these methods are utilised to work out the moral force and besides physical job of any build. These solutions even use to work out the trouble that involved the complex portion in organic structure construction.4.5.1 Heat GenerationThe entire heat coevals rate, Qg can be described as 12 Where R = Rw + Rc + ReRw workpiece mass oppositionRc entire contact oppositionRhenium electrode oppositionI welding currentWelding clipThe heat of merger required for nugget formation, atomic number 72 is 13 Where Hydrogen heat of merger per unit volume Nugget volume ( )The entire heat neediness can be described in three different parts with lumped measures.The entire heat loss 11 Where = denseness= specific heat= volume= temperature risen = in nuggets = in environingvitamin E = in electrodesTherefore, the entire heat balance including the entire heat loss rate, through the theoretical account boundaries can be written as follows The above equation can be rearranged asBy pretermiting the heat loss and temperature rise in the electrodes and the temperature rise in the surrounding, the equation becomes4.5.2 Effect of Geometry and Heat LossBy sing the entire heat loss, the old equation alterations tochangelessThe entire heat loss rate of the nugget, is the amount of the axial heat loss rate through the electrodes, and the radial heat loss through the workpiece.Then, the axial loss rate 11 Where thermic conductivity thaw temperature interface temperature at workpiece distance from runing interface to electrode contact surface nugget wheel spoke.The heat required for temperature rise in environing nugget stuff is determined by the heat flux out of the nugget and the heat coevals in environing stuff itself. The temperature distribution in this part is assumed to be determined by when the nugget growing to sufficient size. If the heat loss through the workpiece is assumed to be relative to the country of the nugget side wall, soWhere characteristic surrounding temperature feature heat diffusion lengthThe thermic conduction includes in the heat loss equation alterations with temperature while the interface temperature is besides affected by geometry and interfacial feature. This is besides affected by heat coevals due to the electrical electric resistance alteration with temperature. 11 The comparing of heat loss in axial and radial way can be determined by the growing of the nugget. The ratio of axial heat loss to the radial heat loss is given byBy presuming that the nugget size is straight person relat ive to the geometry of the electrode and the thickness, soWhere incursion concluding incursion to workpiece thickness ratio electrode contact surface universal gas constantThen, the concluding ratio becomes,By presuming that the nugget front revises its place at every half rhythm or ( 1/120 sec ) in AC welding, so the ratio becomesThe entire heat loss can be described as a map of 11 4.5.3 The Principle of Electrical DistributionThe rate of heat coevals depends upon the flow of current, in amperes, through the opposition of the stuff. Other electrical factors, such as electromotive force, frequence and power factor, enter into consideration merely with regard to their uniformity. They affect merely the value of the current.Harmonizing to Ohmis LawWhere current electromotive force bead across the electrodes opposition through the stuff in OhmThe entire heat in Watt-seconds is generated in the welding electrodes is expressed byOr Where T is clip in 2nd. 14 4.5.4 Formulation for Elect ric AnalysisIn two dimensional jobs the regulating equation of the electric possible distribution is expressed by the Laplace equation 15 ( ? 2i ) / ( ? x2 ) + ( ? 2i ) / ( ? y2 ) =0Where i = i ( x, Y, T ) is the electrical potency as a map of co-ordinates and clip. The finite element transition of this equation can be formulated in the same manner as in the 3-dimensional analysis, and there are two sorts of boundary conditions to be specified in the electric analysisi=i_0On the boundaries in contact with the power supply with known possible i_0 and( ? i ) / ? n=0on the free boundaries, where N denotes the normal way of a boundary. After finding the possible distribution, the current denseness can be calculated as, J_y=-1/ ? ( ? i ) / ? YWhere J is current denseness and? is electric electric resistance. The heat coevals rate per unit volume is calculated utilizing the expressionQ= ? iJ24.5.5 Formulation of Thermal AnalysisThe regulating differential equation for planar transient h eat conductivity with an internal heat beginning is / ? ten ( k? T/ ? ten ) + ? / ? Y ( k? T/ ? Y ) +Q= ? iC? T/ ? TWhere T is the temperature as a map of co-ordinates and clip, K is the thermic conduction, ? is the mass denseness, and C is the heat capacity per unit mass. The three types of boundary conditions involved areT=T0On the boundaries with the specified temperatures,-k? T/ ? n=0On the lines of symmetricalness, and-k? T/ ? n=h ( T-T_e )On the free surfaces, the effectual heat transpose is taken into history. H is the convection heat transportation rate of the environing air, and Te is the ambient temperature. 15 .Chapter VSTATISTICAL AND EXPERIMENTAL PROCEDURES5.0 Introduction to MINITAB packageMinitab are the package that pattern statistics bundle. Minitab sofware green goods by Minitab Inc that headquartered at Pennsylvania State university by a Barbara F.Ryan Thomas A. Ryan, Jr and brian l. Joiner in 1972. The intent of the minitab is to spreadsheet for better analysi s for informations and file direction. It besides can regression analysis, power and sample size and create tabular arraies and graphs for the experiments. For many variables that is used it can multivariate analysis that include factor analysis, flock analysis and corresponce analysis. And it besides functional to analysis the discrepancy to find the difference between the information points.In this research, practicality of minitab package is to plan of experiment and testing design or factorial design to place which factor that consequence the response variables. Factorial design is to plan the experiment where the input factors are ste at two degree each. The intent of the factorial design is to place the important consequence on the response, place the interaction of the factors, place the factors hat have most importance effects on the response, to make up ones mind for the farther probe that which factors should to be bead in causes the factor is non important.5.1 Design of Experiment processThe building of the design of experiment is carried out in MINITAB package. the measure procedures to make the desgin of experiment are provided in the sub-section as follows5.1.1 Launch and Creation of New FileTo establish the MINITAB16, open the MINITAB16 booklet and choose the MINITAB16 icon. Once file is opened the board like figure 5.1 will look.Figure 5.1 MINITAB 16 ScreenAfter the panel appear, create the new file by snaping on the file and choice New as shown in the figure 5.2 below.Figure 5.2 induced new file5.1.2 Create factorial designTo make factorial design, detent at start clit so choice DOE, factorial so Create Factorial design as shown in figure 5.3 belowFigure 5.3 Create Factorial DesignSince we haved 4 factors which are weld current, weld clip, hold clip and force select 4 figure of factors and chink at 2 degree factorial.Figure 5.4 Choice no of factorsFigure 5.5 Choice no of Center Points Per clotureFigure 5.6 Choice 4 factors and a6 no of t ally5.1.3 Enter the high an depression of the factorsClick the factor button and the rename the factors are used and the enter the high and low value of the factors. For the dyers rocket current the units used is kA ( Ampere ) , weld clip is rhythm, hold clip besides in rhythm and force in kN. Where the equation of rhythm to change over to 2nd is 1/Frequency ten cycles/sec = seconds.5.7 Enter the high and low of the factorsAfter that chink on the option button and consequence and merely snap Oklahoma.Figure 5.8 Option and Consequence5.1.4 Table of the experiment is createdAfter the measure is finished, in conclusion click OK button so the tabular array as shown in figure 5.9 is created. The agreements of the experiment is indiscriminately create by the package. For the experiment parametric quantities and the agreement is harmonizing to the tabular array.Figure 5.9 The Table of Eperiment5.2 Experimental appendage ProceduresIn this research all the experiment procedure all done in t he store and stuff scientific discipline research lab. The procedure of experiment was done by utilizing all the equipment in the module.First, the natural stuff of mild steel have taken from machining workshop. And for DP600, this stuff have been order from PROTON Holdings Berhad. This sheet steel so being cut by utilizing shearing machine as ( Figure 5.10 ) in the machining workshop. The size and form of the specimen have been decided from the diary and the article to acquire the exactly consequence. Therefore, the size of the specimen that have been cut is 110mm ( length ) x 25mm ( breadth ) as shown in ( Figure 5.11 ) .Figure 5.10 Shearing MachineFigure 5.11 specimenAfter finished bitter procedure, the specimen will be clean by wire coppice utilizing the bomber as ( Figure 5.12 ) to take the dust or the oils.Figure 5.12 Bomber with wire coppiceAfter the specimen is ready, it will be welded at the PROTON Holdings Berhad. The machine used is the portable welding machine C- gun t ype as ( Figure 5.13 ) . the power transformer capacity for portable welding machines is the primary dyers rocket electromotive forces is 415 V/ 50 Hz, maximal input is 450 kVA for one welding transformer, and maximal welding current is 18 Ka.Figure 5.13 Welding machineAfter the specimen have been welded ( Figure 5.14 ) , it will travel through a procedure to find the radius of dyers rocket nugget. The procedure will be conducted in the stuff scientific discipline research lab. First the welded sheet steel will be cut by utilizing cutting machine ( figure 5.15 ) . This subdivision of the procedure must be done carefully and the film editings must be at the marrow of dyers rocket nugget where the centre of the dyers rocket nugget is the maximal diameter of the dyers rocket nugget.Figure 5.14 Welded sheet metalFigure 5.15 Stonecutter machineAfter the film editing procedure has been done, the little pieces of the dyers rocket nugget has to be mounted by utilizing mounting machine ( Fi gure 5.16 ) . the procedure will takes about 20 proceedingss to complete one climb. ( Figure 5.17 ) shown the specimen after mounting procedure.Figure 5.16 Climb machineFigure 5.17 After mounting procedureAfter finished the mounting procedure, the specimens will grined utilizing swot machine ( Figure 5.18 ) . The crunching procedure must be grind by utilizing five type os sand paper. The type of sand paper are 240, 320, 400, 600, and 1200. The the specimens must be polished utilizing Polish machine ( Figure 5.19 ) in four phases. After that the specimen will be etched by utilizing ifry regenti semiliquid as ( Figure 5.20 ) . At this point, the welded nugget will be on position with our bare eyes.Figure 5.18 Grind machineFigure 5.19 Polish machineFigure 5.20 iFry regenti liquid at long last, the finished specimen as shown in ( Figure 5.21 ) will be taken to the microscope LEICA DM 6000 ( Figure 5.22 ) . The microscope is connected to the computing machine which used package to take the image of the specimen. The dyers rocket nugget size and Heat Affected zone ( HAZ ) will be measured by this package. The package used is IMAPS Ver. 4.0 Professional Edition.Figure 5.21 specimenFigure 5.22 The microscope LEICA DM 6000IMAPS is an image analyser package that functional to see and dimensional the macrostructure. The important of this package is to detect the macrostructure of stuff.5.2 IMAPS Software ProcedureFirst, put together IMAPS as shown in Figure 5.23 below.Figure 5.23 Image IMAPS SoftwareAfter that, choose on the picture so choice prevue on as shown in Figure 5.24 below.Figure 5.24 Choice prevue OnAfter the package is preview on, puting the fokus of the image on the microscope sunburn click the gaining control button to capture the image of the specimen as shown in Figure 5.25 below.Figure 5.25 Image capturedAfter image is captured, snap the horizontal length button to value the length of the dyers rocket nugget and Heat Affected Zone shown on figure 5.26 below.Figure 5.26 Click Horizontal Length ButtonWhen the horizontal length button is clicked, the line would look to mensurate the length of dyers rocket nugget and heat affected zone ( HAZ ) . The distance of the length weld nugget and heat affected zone ( HAZ ) will be calculated automatically by the package shown in Figure 5.27 below. Once the dyers rocket nugget is measured, stamp button must be clicked to stomp the amount and so follow up to measured heat affected zone. The radius of dyers rocket nugget and heat affected zone so inserted into the tabular array in the MINITAB package.Figure 5.27 Measure length of dyers rocket nugget and Heat Affected Zone ( HAZ )Chapter VIRESULT AND DISCUSSION6.1 PHYSICAL AND MECHANICAL PROPERTIES6.1.1 PHYSICAL AND MECHANICAL PROPERTIES OH 1.0 MM DP 600Mechanical belongingss give look of the elastic and inelastic behaviour of a stuff when force is applied. The intent of mechanical trial is to demo whether a stuff or portion is suited for its in tended mechanical applications by mensurating snap, tensile strength and elongation.To find the mechanical belongingss of a DP 600, tensile trial in used. The intent of tensile trial of DP 600 to guarantee that the output strength of DP600 achieved the criterion.First, before get downing the tensile trial must fix the specimen. DP 600 must be cut with the criterion of 1.0 millimeter thickness steel as shown in figure below.Figure 6.16.1.1.1 Tensile Test Procedure1. Put gage grade on the specimen2. Measure the initial length, thickness and size of the specimen. Thickness is 1 millimeter, breadth is 4 millimeter and length is 35 millimeter3. Put the velocity. Speed used is 2 mm/min4. Maximal burden is recorded in the computing machineThe consequence of the tensile trial is shown in Figure 6.2 and Figure 6.3 below.Figure 6.2 Graph of maximumm burdenFigure 6.3 The Data of Tensile Test6.2 Screening OF THE OPERATING PARAMETERSThe design matrix and consequence of 24 fractional factorial de sign with 21 tallies included four parametric quantities which is weld current, weld clip, hold clip, and two response which is radius of dyers rocket nugget and radius of heat affected zone are given in table 6.1. The experimental sequence which is standard order was randomized in order to minimise the unexpected variableness in the ascertained response.StdOrder RunOrder CenterPt Blocks Parameters Responseweld current dyers rocket clip force clasp clip weld nugget HAZ17 1 0 1 8 15 2.5 3 2.827 3.44413 2 1 1 6 10 3.5 4 2.341 3.1572 3 1 1 10 10 1.5 2 2.815 3.41519 4 0 1 8 15 2.5 3 2.827 3.44011 5 1 1 6 20 1.5 4 2.242 3.2529 6 1 1 6 10 1.5 4 2.265 3.01016 7 1 1 10 20 3.5 4 3.205 3.55212 8 1 1 10 20 1.5 4 3.188 3.3153 9 1 1 6 20 1.5 2 2.364 3.2376 10 1 1 10 10 3.5 2 3.166 3.53510 11 1 1 10 10 1.5 4 2.821 3.41420 12 0 1 8 15 2.5 3 2.807 3.4755 13 1 1 6 10 3.5 2 2.308 3.15718 14 0 1 8 15 2.5 3 2.827 3.4451 15 1 1 6 10 1.5 2 2.255 3.07214 16 1 1 10 10 3.5 4 3.165 3.4454 17 1 1 10 20 1.5 2 3.195 3.3258 18 1 1 10 20 3.5 2 3.215 3.5587 19 1 1 6 20 3.5 2 2.355 3.38015 20 1 1 6 20 3.5 4 2.345 3.38721 21 0 1 8 15 2.5 3 2.807 3.445Table 6.1Figure 6.4 and figure 6.5 shown a normal chance secret plan of standardised effects of dyers rocket nugget and heat affected zone ( HAZ ) at 5 % important degree utilizing Minitab package. Figure 6.4 suggest that the chief effects of weld current, weld clip and force as the interaction consequence the radius of dyers rocket nugget. In return, figure 6.5 suggest that the chief effects of weld current, weld clip and force as the interaction consequence the radius of heat affected zone ( HAZ ) , the point that far from the line normally is a signal of of import effects. The normal chance secret plan identifited importance effects utilizing alpha 0.5.Figure 6.4Figure 6.56.3 Regression ModelTable 6.2 and Table 6.3 shows that the estimated coefficients ( coef ) of the variables footings in a arrested development theoretical account for radius d yers rocket nugget and radius heat affected zone ( HAZ ) . Equation 6.3.1 and 6.3.2 shows coresponding standard divergence ( Sdcoef ) , t-statistic ( T ) and chance ( P ) values are determined at 5 % important degree. Variables footings with P & lt 0.05 for radius dyers rocket nugget is A, B, C, AB, AC and BC and radius heat affected zone ( HAZ ) are A, B, C, AB and BC. These variables are considered as statically important of the responses. Consequently, all the important variables footings that pair with the response for 2nd order multinomial theoretical account in coded are accelerated asRADIUS WELD NUGGET 2.70281+ 0.39344A + 0.06081B + 0.05969C + 0.04369AB + 0.03181AC 0.04331BC ( 6.3.1 )RADIUS HAZ 3.32569 + 0.11919A + 0.05006B + 0.07069C 0.05744AB + 0.02281BC( 6.3.2 )In the equation 6.3.1 and equation 6.3.2, the positive coefficients of the variables illustrated their mutual effects on the radius of dyers rocket nugget and radius of HAZ. Meanwhile the negative coefficients i llustrated their unfriendly consequence. Subsequently, the chief efect A ( weld current ) , B ( weld clip ) , and C ( force ) are the primary operating parametric quantities that influence the radius of dyers rocket nugget. That is consequently to the diminishing significance of each variables respect to their consequence on radius dyers rocket nugget which are A B C AB AC CD AD D BD BD. For the variables term of radius HAZ, the diminishing significance variables respect to their consequence on radius HAZ is A C B BC BD AC CD AD D AB. The chief variables A ( weld nugget ) , C ( force ) and B ( weld clip ) are the primary operating parametric quantities that influence radius HAZ.Table 6.2 Estimated coefficients of the arrested development theoretical account for radius of dyers rocket nuggetTerm Coef SE ( Coef ) T PChangeless 2.70281 0.01407 192.10 0.000Weld current, A 0.39344 0.01407 27.96 0.000Weld clip, B 0.06081 0.01407 4.32 0.002Force, C 0.05969 0.01407 4.24 0. 664Hold clip, D -0.00631 0.01407 -0.45 0.013Weld current *weld clip, AB 0.04369 0.01407 3.10 0.050Weld current*force, AC 0.03181 0.01407 2.26 0.740Weld current*hold clip, AD 0.00481 0.01407 0.34 0.013Weld time*force, BC -0.04331 0.01407 -3.08 0.404Weld time*hold clip, BD -0.01231 0.01407 -0.88 0.592Force*hold clip, Cadmium 0.00781 0.01407 0.56 0.003Table 6.3 Estimated coefficients of the arrested development theoretical account for radius of HAZTerm Coef SE ( Coef ) T PChangeless 3.32569 0.007626 436.08 0.000Weld current, A 0.11919 0.007626 15.63 0.000Weld clip, B 0.05006 0.007626 6.56 0.000Force, C 0.07069 0.007626 9.27 0.000Hold clip, D -0.00919 0.007626 -1.20 0.259Weld current *weld clip, AB -0.05744 0.007626 -7.53 0.000Weld current*force, AC 0.00694 0.007626 0.91 0.387Weld current*hold clip, AD -0.00419 0.007626 -0.55 0.596Weld time*force, BC 0.02281 0.007626 2.99 0.015Weld time*hold clip, BD 0.00994 0.007626 1.30 0.225Force*hold clip, CD -0.00194 0.007626 -0.25 0.8056.4 Model C ompetence CheckingTable 6.4 Analysis of variance of the arrested development theoretical account for radius of dyers rocket nuggetBeginning DF Seq SS F PArrested development elongatedSquare interaction 6 0.08052 4.24 0.026Residual mistake 9 0.02851Lack of deficiency 5 0.02803 46.71 0.001Pure error 4 0.00048Entire 20 2.7535S = 0.0562804 PRESS = 0.364343 R-Sq = 98.96 % R-Sq ( pred ) = 86.77 % R-Sq ( adj ) = 97.70 %Table 6.5 Analysis of variance of the arrested development theoretical account for radius of HAZBeginning DF Seq SS F PArrested developmentLinearSquareInteraction 6 0.063802 11.43 0.001Residual mistake 9 0.008375Lack of deficiency 5 0.007564 7.46 0.037Pure error 4 0.000811Entire 20 0.479548S = 0.0305052 PRESS = 0.166012 R-Sq = 98.25 % R-Sq ( pred ) = 65.38 % R-Sq ( adj ) = 96.12 %Table 6.4 shown the analysis of discrepancy ( ANOVA ) of the arrested development theoretical account for radius dyers rocket nugget at equation 6.3.1 that obtained at 5 % important degree. Each var iables which are additive, square, and interaction and the arrested development theoretical account shown P values is less than 0.05. That proved that it are statistically important. The tabular array 6.4 besides shows that the sample mutation of R-Sq is 98.96 % for % recovery. That is indicated to the regressors in the theoretical account merely 1.04 % of the entire variableness is non explained by the theoretical account. The value of R-Sq ( adj ) is 97.7 % at the tabular array 6.4 which contrasted 1.26 % from the value R-Sq that determined the theoretical account is extremely important.Table 6.5 is the analysis of discrepancy ( ANOVA ) of the arrested development theoretical account for radius Haz at equation 6.3.2 that besides obtained at 5 % important degree. The variables which are additive, square, and interaction and the arrested development theoretical account shown P values is less than 0.05. it besides proved that it are statistically important. The R-Sq in table 6.5 is 98.25 % for % recovery. That is indicated to the regressors in the theoretical account ony 1.8 % of the entire variableness is non explained by the theoretical account. The value R-Sq ( adj ) is 96.12 % at the tabular array 6.5 which besides contrasted 2.13 % from the value R-Sq Thai is determined the theoretical account is extremely important.The competency of theoretical account was besides examined from the normal chance secret plan of standardised remainders for dyers rocket nugget and HAZ are shown in figure 6.6 and 6.7 below. Therefore, as shown in figure 6.6 and 6.7 all the points accumulated along a consecutive line and remainders. Figure 6.6 and 6.7 besides shows that all the fitted values are interior little magnitudes of +/- 0.06 for dyers rocket nugget and +/- 0.04 for HAZ. These illustrate that A, B, C, AB, AC and BC for radius dyers rocket nugget and A, B, C, AB and BC for radius HAZ are the lone important consequence and that the necessary arrested development premise s are satisfied.Figure 6.6 Residual secret plan for dyers rocket nuggetFigure 6.7 Residual secret plan for HAZChapter VII result AND FUTHUR RECOMMENDATION7.0 DecisionIn this survey, the consequence of the design parametric quantities which is weld current, weld clip, force and force that are affected the radius of dyers rocket nugget and radius of heat affected zone ( HAZ ) of the topographic point welding were investigated. The multinomial theoretical accounts were developed to represent relationship between the response and its important factors. These theoretical accounts could be used to foretell public presentation of radius dyers rocket nugget and radius of heat affected zone ( HAZ ) .The showing of assorted runing parametric quantities which is weld current, weld clip, force and hold clip of the development of radius dyers rocket nugget and heat affected zone ( HAZ ) utilizing the 24 full fractional design were admit that all the parametric quantities except hold clip were af fected radius of dyers rocket nugget and radius of heat affected zone ( HAZ ) significantly. A multinomial theoretical account for radius dyers rocket nugget and heat affected zone ( HAZ ) as a map of the important parametric quantities were developed. And the value of R-Sq is 0.9896 and R-Sq ( adj ) is 0.9770 for dyers rocket nugget and R-Sq is 0.985 and R-Sq ( adj ) is 0.9612 for heat affected zone ( HAZ ) . The arrested development theoretical account besides shows the high R-Sq values indicated that the theoretical account is extremely important and would be a good inclination of the response within the experimental subject studied.7.1 Futher RecommendationsIts is recommended that the probe of the topographic point welding parametric quantities to be continue with varied in other parametric quantities such as weld clip, stuffs, weld current and force. Particularly for stuffs besides can analyze for Advanced High Strength Steels ( AHSS ) such as DP780 and DP800due to their advan tages which are to accomplish light burdening and improved structural public presentation.The nugget development and formation consequence is importance to calculate out systematically with the development of automotive engineering.Finally since the machine used in the machine is rather old and without a proper care, the RSW machine demands to be send to graduate once more. The electrode tip besides needs to re-align so that an optimal dyers rocket nugget can be produce.