Steel materials having an excellent hydrogen induced cracking resistance
 Steel materials having an excellent hydrogen induced cracking resistance when used under atmosphere containing H.sub.2 S, which contain 0.05 to 0.20% of C, 0.01 to 0.50% of Si, 0.60 to 2.00% of Mn, 0.01 to 0.10% of Al, less than 0.0020% of S, Ca of 0.0020% to less than 0.0050%. These steel materials are increased in the tensile strength by additionally containing at least one of Cu, Ni, Cr, B, Mo, Nb, V, Zr and Ti. Furthermore the effect of addition of Ca is stabilized by adding rare-earth elements. 
Kawasaki Steel Corporation
C
C22C
inventional
Toshihiko Akitoshi Shinobu Noboru Osamu Shuji Toshiaki Toshio Hiroshi
Emi Fujiwara Okano Okamoto Haida Watanabe Shiraishi Iwasaki Ooi