Dissimilar joining of AISI 304L/St37 steels by TIG welding process

In present work the weldings of an austenitic stainless steel(AISI 304L) and a ferritic carbon steel(St37) were conducted by tungsten inert gas(TIG) welding process using four diferent austenitic filler metals,namely ER308L,ER309L,ER316L and ER310.Microstructure characteristics and mechanical properties of the weldments were studied using optical and scanning electron microscopy,ferrit-ometry,hardness,tensile and impact tests.The ferrite number(NF) of the weldments made by diferent electrodes varies between 0.5 and 9.5.It was found that the increase in amount of delta ferrite in the microstructure of the weld metals,causes the decrease of the impact toughness of the weldments.It seems that using ER309L and ER316L electrodes can provide a good combination between the mechanical and metallurgical properties of the joint in AISI 304L/St37 dissimilar welding.