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利用ZEISS-AXIO金相显微镜、ZEISS-MA10扫描电子显微镜对9Cr2Mo钢冷轧工作辊工频淬火开裂后的断口进行观察,分析了工作辊淬火开裂的原因。结果表明,9Cr2Mo冷轧工作辊淬火开裂断口形貌分别由剪切唇区、放射区以及纤维区3部分组成。断口裂纹源处有明显的白点,其产生原因主要是氢和内应力的共同作用所致。改善方法首先应提高辊坯的冶金质量,降低辊坯中的氢含量;其次应改进锻后热处理工艺,例如采取降低白点敏感性的锻压方法,并对锻后辊坯进行充分的扩氢退火,降低辊坯氢含量和内应力。
Using ZEISS-AXIO microscope, ZEISS-MA10 scanning electron microscope on the 9Cr2Mo steel cold-working roller frequency quenching and cracking after the fracture was observed to analyze the cause of work-roll quenching and cracking. The results show that the morphology of quenched and dehiscent fracture surface of 9Cr2Mo cold rolling work roll is composed of three parts, ie, shear lip zone, radiation zone and fiber zone respectively. There are obvious white spots at the crack initiation source, which is mainly caused by the combined effect of hydrogen and internal stress. The improvement method should firstly improve the metallurgy quality of the roller billet and reduce the hydrogen content in the roller billet. Secondly, the heat treatment process after forging should be improved. For example, the forging method of reducing the white point sensitivity is adopted, , Reduce roller hydrogen content and internal stress.