• CN:11-2187/TH
  • ISSN:0577-6686

›› 2008, Vol. 44 ›› Issue (9): 50-55.

• 论文 • 上一篇    下一篇

碳化物对冷轧条件下轧辊中裂纹行为的影响

徐流杰;魏世忠;邢建东;张永振;龙锐   

  1. 河南科技大学河南省耐磨材料工程技术研究中心;西安交通大学金属材料强度国家重点实验室
  • 发布日期:2008-09-15

Effect of Carbides on Crack Behavior within Rolls under Cold Rolling Condition

XU Liujie;WEI Shizhong;XING Jiandong;ZHANG Yongzhen;LONG Rui   

  1. Henan Engineering Research Center for Wear of Materials, Henan University of Science and Technology State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University
  • Published:2008-09-15

摘要: 利用扫描电镜、透射电镜研究碳化物对冷轧过程中高铬铸铁及高钒高速钢轧辊中裂纹行为的影响。结果表明,裂纹萌生及扩展与碳化物的精细结构、碳化物与基体界面结构及碳化物形态有关。高铬铸铁中的M7C3具有层错结构,轧制过程中M7C3内部易于造成位错塞积而萌生裂纹,经短距离扩展后形成贯穿的主裂纹,导致轧辊迅速失效。高钒高速钢中的VC内部弥散分布着大量富钼的纳米级MC型碳化物,起到钉扎VC内部位错的作用,促使形成位错环而吸收轧制能量,裂纹不易在VC内部萌生,而主要萌生于VC与基体界面,并沿球形VC的表面扩展,扩展到VC侧面时出现裂纹钝化现象。VC与基体界面的部分共格关系能够延缓界面裂纹萌生,VC良好的形态有助于裂纹钝化,提高轧辊的抗疲劳性能及寿命。

关键词: 高钒高速钢, 高铬铸铁, 裂纹, 碳化物, 轧辊

Abstract: The effects of carbides on crack behaviors in high-vanadium high-speed steel and high-chromium cast iron rolls under cold rolling condition are studied by using scanning electron microscope and transmission electron microscope. Results show that the crack initiation and propagation depend on fine-structure in carbide, carbide/matrix interface and morphology of carbide. Dislocation in M7C3 tends to occur in the process of steel rolling owing to the stacking fault structure of M7C3 in high chromium cast iron, resulting in dense crack-initiation sites in M7C3. After propagating a short distance, the dense cracks joint each other to form main crack, causing in rapid failure of roll. There are a lot of MC-type nanometer carbides, enriched Mo, evenly distributed in VC of high speed steel, which can pin dislocation in VC, resulting in forming dislocation loop to absorb rolling energy. So it is difficult for crack to initiate inside VC. Crack mainly initiates at the VC/matrix interface, and propagates along spherical surface of VC. Crack blunting occurs when it propagates to the side of VC. The partial coherent relation between VC and austenite matrix can retard the initiation of cracks located at VC/matrix interfaces, and good morphology of VC is helpful to crack blunting, which contribute to enhancing fatigue performance and service life of roll.

Key words: Carbides, Crack, High vanadium high-speed steel, High-chromium cast iron, Roll

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