宝钢某电镀机组压辊断辊原因分析与改进

Analysis on the fracture and improvement on the structure of the pinch roll of electrolyte tinning line in Baosteel

宝钢某电镀机组压辊在使用过程中,辊筒内部配重块热影响区处频繁断裂,严重影响机组的稳定运行。通过对辊子辊筒弯曲强度进行核算,并从断口宏观、滚筒材料化学成分、滚筒材料力学性能、断口显微硬度和断口金相等角度进行了分析,确认断辊的根本原因是辊筒的弯曲强度不够,再加上焊接辊筒内壁处应力集中,在反复的旋转弯曲应力作用下在焊接影响区产生了裂纹源,最终导致疲劳开裂。依此对压辊的辊壁厚度进行修正,在保证辊身平衡要求的基础上去除了配重结构。经过后续跟踪,改进辊的断辊发生率显著减少,从而为机组的稳定运行提供了保障。

The pinch rolls used in ETL of Baoteel are often cracked at the position of the heat- affected zone of the weight balance inside the roll cylinder, which seriously affected the stable operation of the line. Based on roll bending strength examination, analysis of macro appearance of the fracture and chemical composition of the roll cylinder, fracture surface micro-hardness and macrostructure of the cracking source metallographic examination, the reason of cracking is confirmed that the bending strength of the roll cylinder was not enough and fatigue cracking appeared at the heat-affected zone due to the frequently rotating bending stress. Based on this, measure of revising the thickness of the roll cylinder and getting rid of the weight balance structure based on proving the balance of the roll is adopted. After the followed tracking, the rate of the cracking of the roll is significantly reduced, which provides the guarantee for the stable operation of the line.