材料期刊网

对探伤不合的厚规格(≥25mm)钢板(坯)进行取样，分别做了低倍酸洗、刨削、金相、SEM及能谱分析，分析认为探伤不合的主要原因是中心偏析分层、中间裂纹、中心部位的氢致裂纹、大颗粒外来夹杂(夹渣)，同时夹杂物的存在常是诱发裂纹的起源。在生产压缩比小于6.0的宽厚规格探伤板时，应围绕钢水质量、板坯低倍质量、缓冷时效(≥48h)、轧后时效(≥24h)有针对性选择工艺路线，其中钢水质量主要为钢中气体[H]应控制在2.0ppm以下、[S]控制在0.010%以下、夹杂物水平[O]全控制在25ppm以下；板坯低倍质量主要由过热度(15~25℃)、拉速(根据断面恒拉速)、动态配水、动态软压下、液面控制(±5mm)及设备工况等综合工艺条件决定。

This article makes series of defect analysis by acid washing, planning, metallurgical structure, SEM and energy spectrum analysis in the samples from the plate, which has flaw detection and heavy gauge (≥25mm). It thinks that the mainly reasons of the flaw detection are central segregation layer, inner cracks, inner hydrogen induced cracking and cinder inclusion, at the same time inclusion is usually the origin of cracks. When the heavy gauge plate is produced which has less than 6.0 compression ratio and detection requiring, the production process route should be select after considerations in the steel quality, metallurgical structure quality, slow cool aging (≥48h) and rolling aging (≥24h). At the steel quality, it should be steel gas [H] controlled below 2.0ppm, [S] below 0.010% and total oxygen [O] below 25ppm. And metallurgical structure quality of the slab is mainly decided by the series of process conditions including degree of superheat (15~25℃), cast speed, dynamic secondary cooling system, DSR, liquid level control (±5mm) and equipment work conditions.