不锈钢铸件加工后花斑缺陷分析与改进

Analysis and Improvement of Stainless Steel Casting Mottle Defect After Processing

通过对机加工刀具、切削参数、化学成分、PT检测、金相、铸件结构、热处理等多方面分析,探索不锈钢铸件加工后产生花斑缺陷的原因。结果表明,花斑缺陷是由于铸件壁厚大部位固溶处理时冷却速度过慢,晶间析出块状碳化物,导致产生花斑缺陷。为此采取热处理前将铸件上的型壳完全清理,粗加工去除冒口补贴,可有效改善入水固溶处理的冷却条件,消除花斑缺陷。

Based on the machine tool, cutting parameter, chemical composition, PT testing, metallographic, casting structure, heat treatment and other aspects of analysis, mottled surface appeared on stainless steel casting after machining was explored. The results show that slow cooling rate at heavy section during solution treatment made lump carbide precipitate, thus leading to mottled surface. Cleaning away shell completely before heat treatment and removing riser pads during rough-machining can efficiently improve cooling condition of casting＇ s going into water tank during solution treatment, thus mottled surface can be eliminated.