P92大规格钢锭锻制管坯穿管断裂致因分析  

Cause analysis of breakthrough of P92 large-size steel ingot forged tube billet

作　　者：李成斌 蒋鹏[2] 刘君[2] LI Chengbin;JIANG Peng;LIU Jun(Central Research Institute of Baosteel,Shanghai 201900,China;Steelmaking Plant of Baosteel,Shanghai 201900,China)

机构地区：[1]宝钢股份中央研究院,上海201900 [2]宝钢股份炼钢厂,上海201900

出　　处：《钢铁研究学报》2021年第8期759-766,共8页Journal of Iron and Steel Research

摘　　要：某钢厂生产的P92大规格钢锭锻制管坯常出现穿管后产生裂纹的现象,为了探究裂纹产生的原因,在断裂管坯裂纹及附近区域取样,使用金相显微镜与扫描电镜分析裂纹宏观形貌和成分,并进行夹杂物评级与成分分布分析,对无裂纹产品进行高温拉伸试验,考察热制度是否合理。结果表明:穿管断裂样品均存在夹杂物评级超标的问题,未能在精炼过程上浮去除的脱氧产物与卷渣形成的大型夹杂物在穿管过程中引起应力集中,导致裂纹萌生、扩展。针对脱氧产物未被去除的问题,对钙质脱氧剂和铝脱氧剂的加入量进行调整,并延长RH处理结束的弱搅拌时间。针对卷渣带入的夹杂物,对保护渣成分进行优化,选用低熔点保护渣。结果表明这些措施较好地解决了裂纹萌生的问题,产品夹杂物评级合格,大尺寸夹杂物数量大为减少。The P92 large-size steel ingot forging billet produced by a steel plant often has cracks after passing through the tube, in order to find out the causes of cracks, samples were taken from the cracked billet and its adjacent area. The macro morphology and composition of the cracks were analyzed by metallographic microscope and scanning electron microscope, and the inclusion rating and composition distribution were analyzed. The high temperature tensile test was carried out on the products without cracks, to investigate whether the hot system is reasonable. The results show that all the broken samples have the problem of excessive inclusion rating. The large inclusions formed by deoxidation products and slag entrapment which can not be removed in refining process cause stress concentration, leading to crack initiation and propagation. In order to solve the problem that the deoxidation products have not been removed, the dosage of calcium deoxidizer and aluminum deoxidizer was adjusted, and the weak stirring time at the end of RH treatment was extended. The inclusions brought by the entrapped slag are solved by optimizing the composition of the mold slag and selecting the low melting point mold slag. The results show that these measures can solve the problem of crack initiation, the inclusion rating of the product is qualified, and the number of large size inclusions is greatly reduced.

关 键 词：P92钢管 夹杂物 断裂 高温热塑性 

分 类 号：TF769.9[冶金工程—钢铁冶金]