T. Fukagawa et H. Fujikawa, Effect of small amounts of Ni on liquid-Cu embrittlement in hot-rolled mild steel after high-temperature oxidation, OXID METAL, 52(3-4), 1999, pp. 177-194
The effects of additions of as little as 0.02%Ni to mild steel on the morph
ology of the scale-steel interface and surface cracking were studied during
high-temperature oxidation and subsequent hot-ductility tests of 0.5%Cu-be
aring steel. Liquid-Cu embrittlement occurs in a steel containing 0.5%Cu-0.
001%Ni because of concentrated liquid-Cu layer at the scale-steel interface
over the temperature range of 1100-1300 degrees C. The addition of as litt
le as 0.023%Ni to 0.50%Cu-containing steel recovers the ductility in the ox
idation temperature range of 1250-1300 degrees C. This is because liquid-Cu
particles are occluded into the scale. Thus, the amount of enriched Cu per
unit surface area decreases at the scale-steel interface. It is suggested
that liquid-Cu particle occlusion, which has nor yet been elucidated, resul
ts from heterogeneous enrichment of Ni and heterogeneous oxidation at the s
cale-steel interface.