CrMo合金冷镦钢开裂机理研究  

RESEARCH ON THE CRACKING MECHANISM OF CRMO COLD HEADING STEELS

作　　者：孔祥华[1] 唐晋[1] 孙瑞虹[1] 孙彦辉[2] 孙华 袁国华 李翔 

机构地区：[1]北京科技大学新材料技术研究院,北京100083 [2]北京科技大学冶金与生态工程学院,北京100083 [3]南京联合钢铁有限公司,南京210035

出　　处：《四川冶金》2011年第4期23-28,共6页Sichuan Metallurgy

摘　　要：本文研究了SCM440与SCM435冷镦开裂样品的典型特征。研究结果表明,SCM440大盘卷冷镦表层存在大量裂纹,根据全脱碳层的厚度判断是由于控冷阶段出现问题产生的。SCM435中的大量微细裂纹是在球化退火过程中气氛存在氧化性造成的,而SCM435产生的大约7%的贯通型裂纹,是在铸坯中形成的,通过对铸坯采取扒皮处理,该类裂纹也基本消除。CrMo钢冷镦开裂存在一个共性特征:全脱碳层的形成导致其中的铁素体晶界抗氧化性降低,在CrMo冷镦钢表面形成大量沿铁素体晶界扩展的裂纹,从而导致CrMo系列冷镦钢开裂。全脱碳层的形成可能在铸坯环节,可能在热轧环节,也可能在球化退火工序。The characteristics of CrMo cold heading steels are studied in the paper. The results show that many micro - cracks occurred in the SCM440 coil surface. These cracks may be caused by the wrong cooling parameters after hot rolling. Micro-cracks can also formed in the surface of SCM440 coil due to oxidization of steel during spheroidization. Some macro-cracks（about 7% ） are caused by surface cracks in billet. The formation mechanism of these kinds of cracks is the surface decarburization of CrMo steel and the anti-oxidation property in boundary area of Ferrite phase deteriorated, so the surface decarburization of CrMo steel should be controlled carefully.

关 键 词：冷镦钢 铁素体相变 SCM435 

分 类 号：TG316.192[金属学及工艺—金属压力加工]