HIGH THERMAL EXPANSION STEEL AND HIGH STRENGTH AND HIGH THERMAL EXPANSION BOLT

摘要

PURPOSE: To produce a high thermal expansion steel excellent in cold proof stress, relaxation strength and cold workability by specifying its compsn. consisting of C, Si, Mn, Ni, Cr, Mo, W and Fe. ;CONSTITUTION: This high thermal expansion steel consists of a compsn. contg., by weight, 0.4 to 1.0% C, ≤1.0% Si, 4 to 20% Mn and 8 to 25% Ni, contg. one or more kinds among ≤5% Cr, ≤3% Mo and≤4% W, and the balance Fe with inevitable impurities, furthermore contg., at need, ≤ l.0% V and 0.5% Nb, in which a part of Fe is substituted by ≤0.2% N, and satisfying the inequality:30C-l.34Si+0.5Mn+Ni-0.67Cr-Mo-0.5W-5.3V-10Nb+20N≥27, and in which the coefficient of thermal expansion at an ordinary temp. to 200°C after ≥30% cold working shows 18.5×10^-6/°C or above, cold proof stress shows ≥980MPa or above and cold tensile elongation after 50% cold working shows ≥8%. By using this steel, the high strength and high thermal expansion bolt can be obtd.;COPYRIGHT: (C)1995,JPO