Estimation of 2nd Phase Particle Size on Hot Crack of High Cr-Ni Steel Weld Heat Affected Zone Caused by Constitutional Liquation

概要

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Hot crack of high Cr-Ni stainless steel weld heat affected zone (HAZ) caused by liquationis closely related with constitutional liquation of 2nd phase particles in base metal . If particle size can be reduced In such degree that 2nd phase particles. Are decomposed during weld thermal cycle due t.o welding before constitutional liquation occurs and diffused into base metal matrix and are turned to sol id sol it ion, hot crack sensitivity of HAZ may be immunized. In the prsent study, we obtained critical particle size of such 2nd phase particles using the solution of the case where the particles were brought into contact with semi-infinite solid (base. Metal) according to the Second Low of Fick in diffusion, and HAZ hot crack sensitivity estimated from the theoretical critical particle size determined by this method was compared with the value obtained by hot. Ductility test. As a result, very good correlation was found between these two values, and it has become clear that constitutional liquation vas a principal cause of HAZ hot crack in this type of material. At the same time, it was demonstrated that the estimation hased on critical particle size of 2nd phase in t.he present study is practical ly suitable. As a method to assess hot crack sensitivity caused by liquation of high Cr-Ni steel weld HAZ.
1996-03-20