INFLUENCE OF BASE-ALLOY HARDNESS ON HEAT AFFECTED ZONE LIQUATION MICROFISSURING IN LASER BEAM WELDED INCONEL 738 SUPERALLOY.

摘要

IN 738 was laser beam welded in different pre-weld heat treatment conditions to compare the effect of base alloy hardness with that of grain boundary liquation in influencing HAZ cracking. The extent of HAZ cracking in the welded materials was observed to be largest in a pre-weld heat-treated condition that produced the least grain boundary liquation, while the slightest cracking occurred in a condition with the most intergranular liquation. This variation in the general expectation of influence of intergranular liquation extent on HAZ microfissuring is presented and related to the ability of the base alloy to accommodate welding stress during laser beam weld cooling.