热轧层流辊道内冷辊回水结构的优化改进

针对某热轧厂1 580 mm生产线精轧出口层流辊道内冷辊频繁发生操作侧轴承失效问题,对其原因进行了分析,同时核算了内冷辊受热轴向膨胀后操作侧轴承侧向间隙。结果表明:操作侧轴承侧向间隙满足使用要求,轴承失效和辊筒受热膨胀无关;操作侧轴承失效的直接原因是轴套制造精度低导致骨架油封失效、内冷辊高速旋转“吸水”效应,使冷却回水进入轴承座内部,进一步造成润滑不良进而造成轴承失效。为此,对内冷辊回水结构进行了优化改进:在操作侧轴承座端盖和水套之间增加法兰,延长轴套及安装轴套的轴头,在轴头和轴套之间增加O型密封圈。改进后两年的使用周期内没有发生过轴承失效故障。

Structural optimization and improvement of backwater device of inner cooling roll in hot rolling laminar roll table

In view of the frequent bearing failure of the operating side of the inner cooling roll in the laminar roll table at the outlet of finishing rolling of a 1 580 mm hot rolling production line, the causes were analyzed, and the bearing lateral clearance of the operating side after the axial expansion of the inner cooling roll was calculated. The results show that the bearing lateral clearance of the operating side meets the requirements, and the bearing failure has nothing to do with the thermal expansion of the roller. The direct cause of bearing failure of the operating side is that the skeleton oil seal failure caused by low manufacturing accuracy of the shaft sleeve, and the “water absorption” effect of high-speed rotation of the inner cooling roll makes the cooling backwater enter the inside of the bearing seat, further resulting in poor lubrication and bearing failure. Therefore, thebackwater device of inner cooling roll was optimized and improved, including adding flange between the end cover of bearing seat of the operating side and the water sleeve, extending the shaft sleeve and shaft head of the shaft sleeve, and using O-type sealing ring between the shaft head and the shaft sleeve. After improvement, no bearing failure occurred in two years of service life.