机架辊探伤不合格原因分析

Reason Analysis of Unqualified Result of the Detection Test for the Breast Roll

通过运用金相高低倍检验、化学成分分析、断口及能谱分析等手段,分析28Mn6机架辊超标缺陷的性质及形成原因。结果表明:缺陷为硫化锰夹杂物。原因是采用大气冶炼、大气下注法浇注时产生密集的点状偏析,致使硫化锰夹杂物大量聚集。通过采用真空碳脱氧技术,严格控制冶炼工艺,适当降低浇注温度及速度,提高冷却速度,可避免出现严重的点状偏析。

This paper analyzes the defect features and its formation reasons of breast roll with material 28Mn6 by microscopic and macroscopic metallographic inspection, chemical composition analysis and fracture and energy spectrum analysis. The result shows that the defects are manganese sulfide inclusion. The formation reason is that clustered point segregation is occurred when atmospheric smelting and air bottom pouring to make lots of manganese sulfide inclusion get together. The serious point segregation can be avoided by applying vacuum carbon deoxidization technology, controlling smelting processes, reducing pouring temperature and speed, and increasing cooling speed.