Analysis on dominant influencing factors of on-line life cycle in sink roll system and effective improved methods

•The investigation of Meishan Iron&Steel Ltd indicated the wear between the sleeves and bushings would influence the online life cycle.•Insufficient abrasive resistance of sleeves and improper hardness ratio between sleeves and bushings led to rapid abrasion of sleeves.•When the sleeves was manufactured by higher hardness materials, the online life cycle was increased.

The continuous hot-dip galvanizing line is performed by threading the steel strip through three rolls of the sink roll system (including sink roll, stabilizer roll and correcting roll) submerged in molen zinc. The premature failure of sleeves and bushings of the three rolls would result in increased cost of production and low production efficiency. According to the on-site investigation of Meishan Iron&Steel Ltd and theoretical analysis, it indicated that the dominant influencing factor of online life cycle was the abrasion between the sleeves and bushings. Insufficient abrasive resistance of sleeves and improper hardness ratio between sleeves and bushings led to rapid abrasion of sleeves. When the sleeves were manufactured by higher hardness materials, the online life cycle was increased from less than 15 days to about 20 days.