MIG Welding with Fully Austenitic Filler Metal on Ultra High Strength Steels and Heat Resisting Superalloys

Abstract

Fundamental studies on the prevention of welding cracks of heat resistaing superalloys and ultra high strength steels were made and as a result, developed an economical method of obtaining heat resisting .weld metal with low cracking sensitivity by using fully austenitic Cr-NiMn filler metal containing a certain amount of additional elements and Ar-base mixed shielding gases. These methods are already adopted for welding of heat resisting superalloys, hear resisting steels and low alloy high strength steels, obtaining good results.
The superior properties of the weld obtained by this method are, described in this paper, which are summarized as follows:
(1) High cracking resistance is obtained by eliminating the effects of deleterious impurities such as CrS and NiS.
(2) High heat resistance is obtained by the prevention of -phase formation and the uniform deposition of stable carbide M₂₃C₆ in the austenitic matrix of weld metal.
(3) Good impact properties is obtained at high and low temperatures and also in the case high temperature isheld for a long time.