Optimizing the parameters for friction welding stainless steel to copper parts

Abstract

St-Cu (stainless steel and copper) parts were friction welded with the aim to optimize the process parameters in the present study. The joints obtained with various process-parameter combinations were subjected to a tensile test. Empirical relationships were developed to predict the strength of the joints using RSM (the response-surface methodology) and the coherency of the model was tested. The tensile properties, microhardness variations, SEM, the EDS analysis and X-ray diffraction (XRD) analysis of the welded specimens were evaluated. It was found, with an ANOVA analysis, that the friction pressure/friction time relation has the largest influence on the tensile strength of the joints followed by the rotational speed. However, it was also found that the formation of intermetallics at the interface is responsible for a higher hardness and lower tensile strength of the friction-welded stainless steel-copper joints. Keywords: friction welding, metallurgy, response-surface methodology, tensile strength V predstavljenem delu so bili deli St-Cu (nerjavno jeklo in baker) torno varjeni z namenom optimizacije procesnih parametrov. Spoji, dobljeni z razli~nimi procesnimi parametri, so bili preizku{eni z nateznim preizkusom. Razvite so bile empiri~ne odvisnosti za napovedovanje trdnosti spojev s pomo~jo RSM (Metodologija odgovora povr{ine) in izvr{ena je bila koherenca modela. Ocenjene so bile natezne lastnosti, spreminjanje mikrotrdote, SEM, EDS analiza in rentgenska difrakcija (XRD) zvarjenih vzorcev. Iz ANOVA analize je bilo ugotovljeno, da ima torni tlak/~as trenja najve~ji vpliv na natezno trdnost spojev, sledi pa mu hitrost vrtenja. Ugotovljeno je bilo, da je ve~ja trdota in manj{a natezna trdnost torno varjenih spojev posledica nastanka intermetalne zlitine na stiku nerjavno jeklo-baker. Klju~ne besede: torno varjenje, metalurgija, metodologija odgovora povr{ine, natezna trdnost

Optimization of the process parameters of friction-welded St-Al joints

“…The response contours can contribute to the prediction of responses in the experimental field as observed in the literature. 22,[24][25][26][27] The end of the response plot illustrates the maximum achievable tensile strength. Figures 3 and 4 show that the tensile strength increases with the increasing friction pressure/time ratio and rotational speed.…”

“…[20][21][22][23] The response surface methodology (RSM) is a collection of mathematical and statistical techniques that are useful for designing a set of experiments, developing a mathematical model, analyzing the optimum combination of the input parameters and expressing the values graphically. [24][25][26][27] To obtain the maximum strength, it is essential to have a complete control over the relevant process parameters as demonstrated in the literature.…”