Welding of C67 steel grade sheets : influence of the parameters and PWHT

TIG welding on C67 material with 0.99mm thickness was produced by changing different parameter in order to have minimum hardness on welded part. Test sample were extracted. The aim of this thesis is to characterize the welded sheet by making mechanical tests on welded portion taken from the machine side and operator side. The tests include micro hardness test and microstructure investigation. High hardness was registered in the fusion zone or melted zone, with decrement in the heat affected zone. Mainly two type of process has been done. One is without Post Welding Heat treatment (PWHT) and other is with PWHT by changing different parameters. For without PWHT the welded part rapidly cooled at room temperature. For with PWHT after welding the welded part kept in maintaining phase for 99s at 710 degree. Then it cooled slowly by air at ambient temperature.