Inconel® alloy 690 is nowadays commonly used instead of 600 for the manufacturing of certain components of the primary circuit of pressurized water reactor (PWR) nuclear power plants, due to its superior resistance to corrosion and stress corrosion cracking. However 690 alloy, and the corresponding welding filler metals (types 52 and 152), can be sensitive to a solid state hot cracking phenomenon during welding, called “ductility dip cracking” (DDC) associated to grain boundary cracking. This work is undertaken to determine more precisely the thermomechanical conditions of the occurrence of DDC in two types of materials: filler metals 52M and 152. To do this, we designed a simple hot crack susceptibility test. This test is based on multiple welding beads on a cuboidal mockup. This test clearly demonstrates the effect of multiple passes on the occurrence of DDC. In parallel, hot tensile tests following fast heating were performed to determine the DDC temperature range, to try and correlate DDC to the thermomechanical behavior.

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