To prevent cracking at the time of blooming and to provide excellent sulfide stress cracking resistance by specifying respective contents of C, Si, Mn, P, S, Cr, Ni, Al, N, Mo, and Cu and also specifying cast bloom temp. in the course of blooming.
The stainless steel has a composition consisting of, by weight, ≤0.05% C, ≤0.5% Si, ≤1.5% Mn, ≤0.03% P, ≤0,002% S, 10-14% Cr, 4.0-7.0% Ni, >0.06-0.3% Al, ≤0.08% N, 1.0-3.0% Mo, 1.0-2.0% Cu, and the balance Fe with inevitable impurities and containing, if necessary, 0.001-0.1% Ca and 0.5S to 0.05% Ti. A bloom with rectangular cross section or a billet with round cross section is produced by blooming a continuously cast bloom with the above composition. At this time, cast bloom temp. in the course of blooming is controlled to 1000-1300°C. This steel is subjected to tube making into seamless tube.
SAKAMOTO TOSHIHARU
YAMAMOTO SHUJI
SATO NAOHARU
NAGAYOSHI HARUYUKI
