导卫辊用WC—Co基合金微细晶粒的生成及其磨损机理

Formation of Fine-grains and Wear Mechanism in a WC-Co Based Alloy Used for Guide Roller

采用一种自制的WC-Co基合金作轧钢导卫辊材料,在轧制2000t45钢后用SEM和洛氏硬度计等对其表面形貌及硬度进行了分析和研究。结果表明:合金的主要磨损机制是体积塑性变形、犁沟效应和疲劳磨损。硬度由使用前的56HRC下降到49HRC,硬度下降的主要原因是合金表面部分晶粒在(受到冲击滑动摩擦作用)高速剪切变形条件下发生了动态再结晶,形成了200nm左右的细小晶粒。微细晶粒形成符合一种渐进式位相向差亚晶合并再结晶机制。

A new WC-Co based alloy used for guide roller was prepared. After having been used for rolling 2 000 tons of 45 steel in an iron & steel plant, the worn surface and Rockwell hardness of the alloy were examined by means of SEM and Rockwell hardness tester. The bulk deformation, fatigue and plough were the major wearing mechanism. The hardness of the alloy dropped from 56 HRC to 49 HRC after the alloy was used as a guide roller for rolling of 2 000 tons of 45 steel. Some grains in the worn surface were dynamically recrystallized and very tiny new grains with the size of around 200 nm were formed, which contributed to the decreasing of hardness of the alloy. The very high shear strain-rate was the reason for the forming of the fine-grains. A mechanism of recrystallization has been proposed for the explanation of the forming of fine-grains under this condition.