HRB400热轧带肋钢筋铸坯质量缺陷原因分析及优化

针对HRB400连铸坯脱方、表面及内部裂纹问题,跟踪排查连铸生产过程,发现铸坯质量缺陷主要与结晶器振动参数、二冷工艺、足辊等因素有关。通过将结晶器振程由7.5 mm提高至8.5 mm,结晶器冷却水量由2 300 L/min降低至2 100 L/min,二冷比水量由1.30 L/kg提高至1.56 L/kg,安装结晶器足辊、挡水板,定期检修维护连铸喷嘴、对弧等措施,铸坯脱方率由1.5%降低至0.1%,角部裂纹发生率由3.2%降低至0.6%,中间裂纹不高于0.5级占比由8.3%提高至92.6%,中心裂纹不高于0.5级占比由85.0%提高至100%,铸坯质量明显改善,成品钢筋质量、性能符合要求。

Analysis and optimization of quality defects of HRB400 ribbed steel bar

Aiming at the problems of rhomboidity and crack of HRB400 continuous casting billet, it was found that quality defects of billet were mainly related to mould vibration parameters, secondary cooling system, foot roll and other factors by tracking and investigating. The rhomboidity rate of billet reduced from 1.5% to 0.1%, the rate of corner crack decreased from 3.2% to 0.6%, the proportion of intermediate crack lower than grade 0.5 increased from 8.3% to 92.6%, and the proportion of central crack lower than grade 0.5 increased from 85.0% to 100% by increasing the stroke of mould from 7.5 mm to 8.5 mm, reducing the cooling water volume of mould from 2 300 L/min to 2 100 L/min, increasing the specific water volume of secondary cooling zone from 1.30 L/kg to 1.56 L/kg, installing the mould foot roll and water baffle, regularly maintaining the nozzle, arc alignment and other measures. The billet quality is significantly improved, the rolling process runs smoothly, and the performance of finished product meet requirements.