亚包晶钢铸坯脆性区对表面裂纹的影响  

Influence of Strands' Brittle Zones on Surface Cracks of Hypo-peritectic Steel

作　　者：曾亚南[1] 孙彦辉[1] 艾西[1] 马志飞[1] 刘瑞宁 刘泳 

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]河北钢铁集团石家庄钢铁有限责任公司,河北石家庄050031

出　　处：《钢铁钒钛》2013年第6期79-84,共6页Iron Steel Vanadium Titanium

基　　金：国家自然科学基金(51274032)资助项目

摘　　要：针对微合金亚包晶钢凝固过程中产生大量裂纹缺陷的现状，采用光学显微镜、扫描电镜及能谱分析仪对铸坯表面裂纹进行分析，并对析出物进行热力学计算，利用Gleeble-1500对铸坯热塑性进行分析研究。结果表明：裂纹处存在（Fe，Mn，Si，Al）（S，O）等夹杂物，加剧应力对基体的影响；裂纹处存在Ti-Al（C，N）夹杂物，增加了γ→α转变的脆性，横裂纹敏感性增加。高温脆性区易产生纵裂，断面收缩率（Z）最小值为37．59％，纵裂纹敏感区间为1454～1478℃。900～750℃为低温脆性区，易产生横裂纹，Z最小值为45．24％，横裂纹敏感区间900～750cc。896oC时，铁素体开始析出，使得晶界上进一步集中，导致裂纹发生。In view of large amounts of cracks formed in the hypo-peritectic HSLA steel during solidifica- tion, the cracks on the surface of strands were analyzed by optical microscope, SEM and EDS, and the precipitates were studied by thermodynamic calculation. Furthermore, hot ductility was studied by Gleeble-1500. The results showed that steel matrix was deteriorated by inclusions （Fe, Mn, Si, AI） （S, O） in cracks, and transverse cracking sensitivity was increased by Ti-AI-（C,N） inclusions. The longitude cracks tend to appear in the high-temperature brittle zone with a longitude cracking sensitive range of 1 454 - 1 478 ℃, and the minimum value of Z was 37.59% ; the transverse cracks tend to ap- pear in the low-temperature brittle zone with a longitude cracking sensitive range of 900 - 750 ℃, and the minimum value of Z was 45.24%. Precipitating at 896 ℃, the ferrite led to strain concentration on the grain boundary, resuhting in crack formation.

关 键 词：亚包晶钢 裂纹敏感区 脆性区 铁素体 析出物 

分 类 号：TF777[冶金工程—钢铁冶金]