精轧和吐丝温度对SCM435线材氧化铁皮物相结构的影响

线材的氧化铁皮起着保护线材免锈蚀的作用,但是也需要在酸洗时容易除去。影响铁皮除去或结合力的主要是铁皮的厚度和其物相结构。通过对不同轧制条件下的氧化铁皮厚度、物相结构进行检测分析,研究了精轧温度和吐丝温度对φ12 mm SCM435氧化铁皮物相结构的影响。研究表明,随着精轧温度或吐丝温度的升高,SCM435线材的氧化铁皮厚度均会增加,且在800-900℃短时间就会生成较厚(约20μm)的氧化铁皮;由于Cr的氧化选择性,精轧温度在870℃以上,吐丝温度在810℃以上时,随精轧温度或吐丝温度升高,氧化铁皮中FeO比例提高;但是吐丝温度高于860℃后,物相结构的变化趋缓,FeO的比例变化不大。

Effect of Finish Rolling and Spinning Temperature on Phase Structure of Iron Oxide Skin of SCM435 Wire Rod

Oxide Scale of wire plays a role to protect wire from rust, but it also needs to be removed easily when pickling. The thickness of iron scale and its phase structure are the main factors affecting the removal or adhesion of iron scale. The effects of finishing rolling temperature and spinning temperature on the phase structure of φ12 mm SCM435 scale were studied by testing and analyzing the thickness and phase structure of oxide scale under different rolling conditions. The results show that with the increase of finishing temperature or spinning temperature, the oxide scale thickness of SCM435 wire increases, and a thicker oxide scale (about 20 micron) will be formed in a short time between 800 ℃ and 900 ℃. Because of the oxidation selectivity of Cr, the iron oxide scale has a high FeO ratio when the Rnishing temperature is above 870 ℃ and the spinning temperature is above 810 °C. However, when the spinning temperature is higher than 860 ℃ , the change of phase structure tends to slow down, and the ratio of FeO does not change much.