免退火20CrMnMo盘条磷化工艺优化

Phosphating process optimization for annealing free 20CrMnMo wire rod

分析免退火20CrMnMo盘条磷化成膜质量差原因,盘条氧化铁皮较薄不利于机械剥壳去除,残留的氧化铁皮和表层全脱碳组织影响磷化过程盘条表面pH值和金属离子浓度,不利于形成均匀的磷化膜。生产过程中进行坯料角部修磨,适当降低加热温度至1060~1080℃,严格控制加热炉内残氧量不大于2%,消除盘条表层全脱碳组织。通过提高终轧温度至850℃、吐丝温度至840℃后,使氧化铁皮厚度由6~10μm提高至14~20μm,氧化铁皮剥离性能改善明显。工艺优化后盘条磷化膜均匀致密,成品表面色差和粗糙度超标问题得到解决。

To analyze reasons for poor phosphating film of annealing free 20CrMnMo wire rods,the thin oxide scale of wire rod is not conducive to mechanical shelling removal,and residual oxide scale and fully decarburized surface structure affect pH value and metal particles concentration on wire rod surface during phosphating process,which is not conducive to formation of uniform phosphating film.During production process,billet corners are polished,heating temperature is appropriately reduced to 1060~1080℃,and residual oxygen content in heating furnace is strictly controlled to not exceed 2%,eliminating complete decarburization structure on wire rod surface.By increasing final rolling temperature to 850℃and laying temperature to 840℃,oxide scale thickness is reduced from 6~10μm increase to 14~20μm.Significant improvement in iron oxide peel performance.After process optimization,wire rod phosphating film is uniform and dense.The problem of color difference and surface roughness of finished product has been resolved.