PURPOSE: To obtan platelike steel products with enhanced resistance to SR embrittlement by reducing the C content, specifying the Ni, Si and Mn contents, and further adding one or more among Mo, Cu and Cr so as to specify the vol. precentage of ferrite.
CONSTITUTION: A steel consisting of ≤0.08% C, <3% Ni, ≤0.5% Si, ≤2% Mn, one or more among ≤2% Cu, ≤3% Cr and ≤2% Mo, and the balance Fe with impurities is hot-rolled to platelike steel products each having ≥30mm thickness and contg. ≥30vol% ferrite and <10% pearlite. By this composition, high resistance to embrittlement due to stress relief annealing (SR) is provided, and the mechanical characteristics such as strength and notch toughness can be maintained properly after SR. The steel products are applied to a pressure vessel, etc.
NIIKURA MASAKAZU
TAKANO TOSHIO
| JPS5395120A | 1978-08-19 |