Abstract: Production practice at steel works shows that the surface quality of hot-rolled strip with thickness less than 9mm is better but the surface iron scale of hot-rolled strip with thickness more than 9mm is thick easily to come off during uncoiling process and press-in surface led to dent defect, and its structure is loose easily to absorb moisture from air led to rust spot and mottled spot defects. The oxidation process, forming mechanism in process and forced condition in uncoiling of iron scale are analyzed, and the control technology of iron scale thickness and structure is put forward. The results pilot production of 9.5mm hot-rolled strip coil of steel SPHC (/%: 0.02〜0.06C, ≤0.10Si, 0.20~0.50Mn, ≤0.035P, ≤0.035S, ≤0.01Alt) show that with the process measures including decreasing heating temperature from 1200℃ to 1180 °C , increasing outlet temperature and rolling speed of finishing rolling respectively from 860°C and 5.0 m/s to 880°C and 6.5 m/s, decreasing coiling temperature from 600℃ to 520℃ , and single-stocking of coil, the scale thickness of steel strip decreases from original 10.093~18.94μm to 6.613μm, the iron scale come off phenomenon is no-occurrence at production situ and the surface dent defects of strip after pickling decreases markedly.

摘要： 钢厂生产实践表明,厚度9mm以下薄规格热连轧带钢表面质量较好,厚度9mm以上厚规格热连轧带钢表面氧化铁皮较厚,且结构疏松,较厚氧化皮易在钢卷开卷过程脱落,压入钢卷表面造成凹坑缺陷;疏松的氧化铁皮易在钢卷储存过程中从空气中吸潮,造成钢卷点锈,继而产生麻点缺陷。分析了钢的氧化过程,氧化皮形成机理和弯曲过程受力情况,提出氧化铁皮厚度和结构的控制工艺。9.5mm SPHC钢（/%:0.02~0.06C,≤0.10Si,0.20~0.50Mn,≤0.035P,≤0.035S,≥0.01Alt）热轧卷的生产试制表明,通过将加热温度从1200℃降至1180℃,精轧出口温度和速度由860℃和5.0m/s分别提高至880℃和6.5m/s,卷取温度由600℃降至520℃,卷后单独堆放等工艺措施,使带钢的氧化铁皮厚度由改进前的10.093~18.94μm降至6.613μm,生产现场基本无氧化皮脱落现象,酸洗后表面凹坑明显减少。

关键词: 低碳钢SPHC, 9.5mm带卷, 氧化铁皮, 控制技术