Low thermal expansion cast steel and method of producing same

Abstract

A low thermal expansion cast steel having a sufficient strength even at a high temperature and having a low coefficient of thermal expansion, that is, a low thermal expansion cast steel comprising, by mass %, C: 0 to 0.100%, Si: 0 to 1.00%, Mn: 0 to 1.00%, Co: 8.0 to 13.0%, and Ni satisfying −2.5×% Ni+85.5≤% Co≤−2.5×% Ni+90.5 (% Ni and % Co respectively being contents of Ni and Co (mass %)) and having a balance of Fe and unavoidable impurities and having, upon being subjected to suitable heat treatment, a 0.2% proof stress of a tensile test at 300° C. of 125 MPa or more, having an average coefficient of thermal expansion at 25 to 300° C. of 4.0 ppm/° C. or less, and having a Curie temperature of 250° C. or more.

Dependencies are inferred from the claim text.