吐丝温度与风冷速率对HRB400E带肋钢筋表面锈层结构的影响

Effect of laying temperature and air cooling rate on the red rust defects of HRB400E ribbed bar

针对HRB400E带肋钢筋盘条生产中的红锈问题,采用热力模拟试验机模拟生产工艺并对吐丝温度和风冷速率进行了控制,采用扫描电镜和能谱仪,分析了不同工艺条件下试样表面氧化铁皮的组成结构;结合试样表面质量,研究了吐丝温度和风冷速率对试样表面氧化铁皮结构和红锈形成的影响。结果表明:风冷速率为4℃/s时,随着吐丝温度从800℃降至700℃,先共析Fe;O;的数量逐渐减少,无红锈缺陷;风冷速率降为2℃/s时,吐丝温度越低,越易出现红锈缺陷;吐丝温度为750℃时,随着风冷速率由6℃/s降至2℃/s,先共析Fe;O;数量逐渐增多,氧化层越易开裂且出现红锈缺陷。

Aiming at the problem of red rust defect of HRB400 E ribbed bar production, the thermo-mechanical simulator was used to simulate the production process, and the laying temperature and air cooling rate were controlled. The composition and structure of oxide scale on the sample surface under different process conditions were analyzed by scanning electron microscope and energy dispersive spectrometer. Combined with the surface quality of the sample, the effects of laying temperature and air cooling rate on the formation and structure of red rust were studied. The results show that when the air cooling rate is 4 ℃/s, the number of pre eutectoid Fe;O;decreases gradually, with the laying temperature decreasing from 800 ℃ to 700 ℃, and there is no red rust defect. When the air cooling rate drops to 2 ℃/s, the lower the laying temperature is, the more prone to red rust defects appear. When the laying temperature is 750 ℃, with the air cooling rate decreasing from 6 ℃/s to 2 ℃/s, the amount of pre eutectoid Fe;O;gradually increases, and the oxide layer is more prone to cracking and resulting in red rust defects.