NON QUENCHED AND TEMPERED STEEL AND MANUFACTURING PROCESS THEREOF

摘要

A non quenched and tempered steel and manufacturing process thereof. The process comprises a cooling step after the finish rolling step; and the process utilizes alternate intense cooling and moderate cooling. The intense cooling can ensure the surface temperature of the steel to decrease rapidly; and the moderate cooling allows the core temperature of the steel to dissipate gradually to the surface; a further intense cooling is carried out to allow rapid heat dissipation. The intense cooling and the moderate cooling can be carried out alternately several times according to practical requirement. A water cooling mode combining intense cooling and moderate cooling allows the core temperature and the surface temperature of the steel to become the same within a short time, and thus ensures the uniformity of the mechanical properties of the steel and improves the production efficiency.

主权项

1. A non quenched and tempered steel, comprising following chemical components by weight percent: carbon 0.35 to 0.47, silicon 0.30 to 0.60, manganese 1.20 to 1.60, chromium 0.00 to 0.30, aluminum 0.010 to 0.030, nickel 0.00 to 0.10, copper 0.00 to 0.20, phosphorus 0.000 to 0.030, sulfur 0.020 to 0.050, vanadium 0.050 to 0.250, nitrogen 0.012 to 0.020, and balance iron.