Development of Welding Processes for Joining of Steel to Cast Iron for an Automotive Axle Application

Welding of cast iron to steel for critical application in automobile requires careful selection of welding processes, parameters and thorough validation of process as well as product. This paper describes selection of welding process and parameters based on laboratory trials and using the same to produce axle assembly in mass production. The welding trials were carried out with different combinations of heat input, preheating and post weld treatments. Microstructure and micro hardness examination was done in the fusion, partial fusion & heat affected zones. Based on these laboratory trials, suitable weld parameters were defined for welding of rear axle assembly used in a mid sized passenger car. The metallurgical and mechanical properties, quasi static push out test and fatigue tests were evaluated on welded axle assemblies to finalize the welding process. Non-contact strain measurement was carried out on the welded axle assembly using Electronic Speckle Pattern Interferometry to establish correlation with fatigue test results.