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采用酸洗、光学显微镜以及扫描电镜—能谱(SEM+EDS)等方法,分析了Q195冷镦钢轧材及冷镦试样的表面质量、裂纹形貌、金相组织、氧氮含量和非金属夹杂物对冷镦钢开裂的影响。结果表明,钢中T[O]含量为154×10-6,钢中夹杂物含量较高;在轧材裂纹处发现大尺寸夹杂物,同时在轧材靠近边缘1/4处发现较多大尺寸夹杂物聚集分布现象,其成分与连铸结晶器保护渣成分相似,大型夹杂物在冷镦过程中引起应力集中从而导致和加剧冷镦开裂程度。同时由于轧制工艺控制不当,使得产品表面形成折叠缺陷,产生180°通条对称纵裂纹,是导致冷镦开裂的主要原因。
The surface quality, crack morphology, microstructure, oxygen and nitrogen content and non-oxygen content of Q195 cold heading steel and cold heading sample were analyzed by pickling, optical microscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM + EDS) Effect of Metal Inclusions on Cracking of Cold Heading Steel. The results show that the content of T [O] in steel is 154 × 10-6, and the content of inclusions in steel is high. Large inclusions are found in the crack of the rolled material, and more large size Inclusion accumulation phenomenon, its composition and continuous casting mold powder composition, large inclusions in the cold heading process caused by stress concentration, leading to and aggravate cold heading degree. At the same time due to improper control of the rolling process, making the product surface folding defects, resulting in 180 ° vertical symmetrical longitudinal cracks, leading cold forging cracking the main reason.