Production manner null of the material for the bearing which is superior in convolution fatigue

摘要

PURPOSE:To drastically simplify soaking holding time by continuously casting the molten steel of specific over-heating degree containing the specific wt.% of C, Si, Mn and Cr and executing squeezing work near crater end, where solidification in inner part of a cast billet is completed, at the specific draft and hot-working after executing soaking treatment. CONSTITUTION:The molten steel containing wt.% of 0.60-1.50% C, 0.15-2.00% Si, 0.15-2.50% Mn, 0.50-3.0% Cr and the balance of Fe with inevitable impurities, is heated to the temp. of over-heat by =25 deg.C of molten steel and after that, the continuous casting is executed. The squeezing work is executed near the crater end, where the solidification in the inner part of cast billet is completed, at =5% draft and successively, the hot-rolling is executed after executing the soaking treatment. In the molten steel, further, 0.05-1.50% Mo. 0.05-0.50% V, etc., are incorporated. The soaking treatment is executed under condition at 1100-1250 deg.C for 2-10hr. By this method, a raw material for bearing having excellence in forgeability and service life characteristic to rolling fatigue, can be obtd.