| 摘要 |
PURPOSE:To manufacture a steel having superior carburization hardenability by controlling the shape of AlN precipitated while keeping the amount of Al and N at conventional levels. CONSTITUTION:An Al killed steel having a composition consisting of, by weight, <0.1% C, <0.06% Si, 0.1-0.5% Mn, 0.01-0.04% Al, <0.006% N and the balance Fe with inevitable impurity elements is continuously cast. The resulting hot steel billet is cooled to 750 - the Ar3 point, heated to 1,000-1,150 deg.C, and rolled at a finishing temp. above the Ar3 point and 250-500 deg.C coiling temp. Thus, AlN is forcibly precipitated and coarsened, and is made harmless. |
