| 摘要 |
PURPOSE:To obtain a titled alloy sheet having a small coefft. of thermal expansion in a temp. region of 200--196 deg.C and has excellent rust resistance, etc. by cold rolling a hot rolled steel strip of an Fe-Ni alloy formed by incorporating a slight amt. of Co and Cr into a base component in a specific draft range then subjecting the strip to final annealing. CONSTITUTION:A hot rolled steel strip of an Fe-Ni alloy contg. 30-45% Ni, 0.05-1.0% Co and 0.10-5.0% Cr is treated in the following way. The hot rolled steel sheet is cold rolled at 50-80% draft in the case of a one-stage cold rolling. The sheet is cold rolled in the draft range of 50-80% in the 1st stage and 30-72% in the 2nd stage in the case of a two-stage cold rolling method and within a range of 50-80% in the 1st stage, 30-72% in the 2nd stage and 30- 72% in the 3rd stage in the case of a three-stage cold rolling method, respectively. The hot rolled steel sheet after such cold rolling is subjected to final annealing at, for example, 800 deg.C. The low thermally expanding Fe-Ni alloy sheet which has excellent resistance to rust and permits a decrease in the plane anisotropy of mechanical properties is thus obtd. |
