PURPOSE: To obtain the titled cast steel contg. prescribed percentages of C, Si, Mn, P, S, Ni, Cr, Mo, V, sol. Al and Ti, having high tensile strength, superior weldability and toughness at low temp., and suitable for use in the centrifugal casting of a thick cast steel pipe of a large diameter.

CONSTITUTION: This high tension cast steel for centrifugal casting consists of 0.07W0.15% C, 0.2W0.5% Si, 0.8W1.5% Mn, ≤0.02% P, ≤0.02% S, 2.5W3.0% Ni, 0.25W0.75% Cr, 0.35W0.55% Mo, 0.05W0.1% V, 0.01W0.1% sol. Al, 0.005W0.015% Ti and the balance Fe with impurities. The cast steel has ≥80kg/mm2 tensile strength, toughness at low temp. expressed by ≥about 8kg.m Charpy impact absorption energy at -40°C and high weldability when subjected to diffusion treatment, hardening and tempering after centrifugal casting.