碳和磷对热轧带钢氧化铁皮起泡行为的影响

Effects of C and P on blistering behavior of scale of hot rolled strip

氧化铁皮的起泡行为发生在热轧过程,当铁皮发生起泡现象时,铁皮界面气体压力增加造成铁皮被顶起,在热轧轧制中起泡的铁皮被碾碎易于形成麻点和铁皮压入缺陷。通过热重分析手段和扫描电镜微观观察研究了超低碳钢、超低碳含磷钢、低碳钢、中碳钢在加热过程中铁皮的起泡行为,重点探讨了磷和碳元素对铁皮起泡行为的影响。研究表明,在980℃附近磷元素形成Fe3(PO4)2,此相高温下易于熔融气化造成铁皮起泡;在1 050℃以上的高温区间,碳元素活性增高,随着铁皮生长界面碳元素的富集氧化,形成CO和CO2对铁皮起泡影响明显,高温试样铁皮气孔和裂纹密集。

Blistering of scale occurs during hot rolling process because high pressure gas forms at the interface between steel base and oxide, and the scale would be roiled into steel base in the followed hot roiling process, resul ting in pitting scale or typical rolled-in scale defect. The blistering behavior of scale of super low carbon steel, super low carbon steel containing P, low carbon steel, middle carbon steel during heating process was investigated through thermo-gravimetric experiment and SEM analysis, especially focusing on the effects of P and C on blistering behavior of scale. The results show that reaction product of P element around 980℃at the interface is Fe3 （PO4）2 which will melt and vaporize under high temperature to result in blistering of scale. Severe gas hole and crack can be found in scales of samples above 1 050℃ because of formation of CO or CO2 as a result of high reac- tion activity of C element and the enrichment of C element at the interface.