METHOD FOR STRAIGHTENING

摘要

A method for straightening a steel material, the method comprising using superhard straightening rolls, the material of which is a tungsten carbide-cobalt (WC-Co)-based sintered object (superhard alloy). The method for straightening is characterized in that the superhard rolls have a hardness of HRA85-87. According to this straightening method, when a steel material is straightened, the rolls are inhibited from wearing and the surface of the material being straightened is prevented from suffering a flaw due to wear. In addition, the period required for roll replacement can be shortened to improve the operating ratio of the straightener and to attain an improvement in the efficiency of precise finishing and hence in productivity. The method is especially effective in the case where the material to be straightened is a high-strength material, e.g., a steel pipe for automotive air bags.