Strain-Induced Stress Corrosion Cracking in Steels in Liquid Metals

摘要

Intercrystalline cracks in steels may be caused by corrosion from liquid metals (LME = liquid metal embrittlement) as well as by electrolytes. They were observed on both stainless chrome and chrome nickel steels and on low-alloy or unalloyed steels. Structural components under tensile stress are particularly at risk, for example during brazing and hot dip galvanizing. Considerable safety hazards and economic losses are connected with cracks forming in steel melting vats used for lead refining and galvanizing since large quantities of liquid metal may flow out. A working hypothesis for crack development is discussed. The liquid metals and steels seem to provide no possibilities for preventing LME-damages. Lower critical limit values for tensile stress and strain rate are to be determined by means of special investigations; these values may form a basis for establishing design and operating characteristics which will enable designers and plant operators to prevent LME-cracks from forming. (ERA citation 10:002724)