WELDED JOINT CRACKING IN MARTENSITIC STAINLESS STEEL PRECIPITATION-STHREGTHENED WITH COPPER

摘要

Problem of welded joint cracking in the HAZ of Cu strengthened 17-4PH grade precipitation hardening martensitic stainless steel is presented. Hypothesis concerning hydrogen embrittlement origin of the cracks is opposed. It was concluded that the cracks located in the high-temperature zone of the HAZ exhibit characteristics of hot cracks which originated as a result of steel embrittlement in the presence of Cu rich liquid phase. The mechanism of steel surface enrichment in Cu is proposed. Practical methods of cracks elimination are presented.