冷镦钢开裂的原因分析及改进  

Cause analysis and improvement of cracking of cold heading steel

作　　者：李静远 杨树峰[1] 李京社[1] 丑英玉[2] LI Jing-yuan;YANG Shu-feng;LI Jing-she;CHOU Ying-yu(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Technical Center,Fushun Special Steel Co.,Ltd.,Fushun 113001,Liaoning,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]抚顺特殊钢股份有限公司技术中心,辽宁抚顺113001

出　　处：《中国冶金》2019年第3期19-23,共5页China Metallurgy

基　　金：国家自然科学基金资助项目(51674023)

摘　　要：为了研究冷镦钢开裂的原因和过程,取样分析了某钢厂生产中存在开裂的试样,利用带有能谱仪的扫描电镜(SEM-EDS)观察开裂区域宏观形貌和微观组织并表征夹杂物的形貌和成分。结果发现,部分魏氏体混杂在基体中,降低了冷镦钢的塑性和韧性;开裂区域发生穿晶断裂和氧化脱碳现象,其完全脱碳层的平均厚度为28μm,说明表面缺陷在轧制前就已经存在,导致冷镦钢轧制时开裂;残留在钢中的铝镁钙复合夹杂物也直接导致了表面缺陷和开裂。同时,提出改善微观组织、减少夹杂物的改进措施。In order to study the causes and processes of cracking of cold heading steel,the specimens with cracking produced in a steel mill were sampled and analyzed.Scanning electron microscopy(SEM-EDS)with an energy dispersive spectrometer was used to observe the macroscopic morphology and microstructure of the cracked area and characterize the morphology and composition of the inclusions.It was found that part of the Widmanstatten structure was mixed in the matrix,which reduced the plasticity and toughness of the cold heading steel.Transgranular fracture and oxidative decarburization occurred in the cracked zone,and the average thickness of the complete decarburized layer was 28μm,which indicated that the surface defects existed before rolling,resulting in cracking of the cold heading steel during rolling.The residual aluminum-magnesium-calcium composite inclusions in steel also directly led to surface defects and cracking.At the same time,improvements were proposed to improve the microstructure and reduce inclusions.

关 键 词：冷镦钢 魏氏组织 夹杂物 位错 

分 类 号：TG142.1[一般工业技术—材料科学与工程]