Surface Defect Analysis and Process Improvement of Non-quenched and Tempered Steel 38MnS6L
In this paper, the non-quenched and tempered steel 38 MnS6 L with the surface cracks was analyzed and studied by means of metallographic microscope, scanning electron microscopy (SEM), EDS and EPMA.The results show that because the heating temperature of the steel is too high, the oxide scale on the surface of steel billet and Si elements enriched on the interface of steel matrix formed the composite oxides of Si and Fe after oxidation at high temperature to embed into the steel matrix with strong adhesive force, resulting in descaling not clean. In the subsequent rolling process, the uncleaned oxide sclae was pressed into the matrix with flowing metal to cause the continuous crack defects on the surface of round steel. Through ajusting the tapping temperature from 1150 ～ 1200 ℃ to 1100 ～ 1150 ℃ and the tapping rhythm from 6 min/branch to 4.5 min/branch, the descaling effect on round steel surface was obviously improved. The qualified rate of magnetic flux leakage inspection on the surface of round steel was increased from 44％ to over 97％, and the surface quality of steel was greatly improved.
non-tempered and tempered steeloxide scaleheating processsurface quality
NETL
NSTL
万方数据
维普
