2507超级双相不锈钢板坯修磨过程脆断分析及控制  

Brittle fracture analysis and control of 2507 super duplex stainless steel slab during grinding

作　　者：陈兴润 成国光[1] 乔通 鲍道华 钱张信 潘吉祥[2] CHEN Xingrun;CHENG Guoguang;QIAO Tong;BAO Daohua;QIAN Zhangxin;PAN Jixiang(State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China;Hongxing Iron and Steel Co.,Ltd.,Jiuquan Iron and Steel Group Corporation,Jiayuguan 735100,Gansu,China)

机构地区：[1]北京科技大学钢铁冶金新技术国家重点实验室,北京100083 [2]酒钢集团宏兴钢铁股份有限公司,甘肃嘉峪关735100

出　　处：《中国冶金》2023年第10期98-104,共7页China Metallurgy

摘　　要：由于含有两相组织,2507超级双相不锈钢在修磨过程中容易出现板坯脆断的技术难题。采用光学显微镜、电子探针(EPMA)、电子背散射衍射(EBSD)、微区纳米硬度检测等分析手段对2507超级双相不锈钢板坯修磨过程脆断原因进行了分析,并借助热力学软件对2507超级双相不锈钢从液态到200℃冷却过程的凝固相图和CCT曲线进行了计算。结果表明,2507超级双相不锈钢板坯脆断样品中存在大量微裂纹,sigma相的面积分数平均值达到24.5%。sigma相的大量析出,一方面导致铸坯组织内应力增大,另一方面由于sigma相硬度高,导致微区各相硬度差增大,加剧了变形的不协调性,使得材料塑性降低,从而发生脆性断裂。400~1 000℃温度范围均为sigma相的产生区间,适当减薄连板坯的厚度,板坯下线后采用水冷或者板坯单独堆放的方式加快冷却,可以有效解决2507超级双相不锈钢的板坯脆断问题。Due to the presence of two-phase micro structure,2507 super duplex stainless steel is prone to produce the technical problem of slab brittle fracture during grinding production.The brittle fracture cause of 2507 super duplex stainless steel slab during grinding was analyzed by means of optical microscope(OM),electron probe microanalysis(EPMA),electron back-scattered diffraction(EBSD)and micro-hardness test.The phase diagram and CCT curve of 2507 super duplex stainless steel in the cooling process from liquid to 200℃ were calculated by means of thermodynamics software.The results show that there are large number of microcracks in the brittle fracture sample of 2507 super duplex stainless steel slab,and the average area fraction of sigma phase reaches 24.5%.The large amount of precipitation for sigma phase leads to increase of internal stress in the casting slab on the one hand,and on the other hand,due to the high hardness of sigma phase,the hardness difference between different phases in the micro zone increases,exacerbating the disharmony of deformation,resulting in decrease of material plasticity and brittle fracture.The temperature range of 400-1000℃ is the generation range of sigma phase.The problem of brittle fracture can be solved effectively by reducing the thickness of continuous casting slab appropriately and using water cooling or separate stacking of slabs to accelerate cooling after they are taken off the production line.

关 键 词：2507超级双相不锈钢 板坯 脆断 sigma相 冷却速率 热力学计算 

分 类 号：TG142.71[一般工业技术—材料科学与工程]