大规格82B高碳钢盘条难酸洗原因研究

针对酒钢生产的大规格φ10.0~φ16.0 mm 82B盘条表面磷化膜在拉丝工艺中易脱落,氧化层中难酸洗的Fe₃O₄含量相对较高,拉拔困难的问题,选用酒钢和A钢厂生产的φ12.5 mm规格82B盘条,用SEM观察盘条表面氧化层厚度和结构组成,用EDS分析氧化层各层元素的分布,用XRD检测氧化层物相的种类和比例。结果发现,酒钢生产的盘条表面粗糙度大,氧化层在盘条表面呈犬牙交替的结合方式;Fe₃O₄的质量分数较A钢厂盘条高39.1%,含CrSi₂层也较致密。为此,对生产工艺提出了优化措施,通过降低吐丝温度和提高冷速,来提高易酸洗相FeO的比例,减少在共析反应最激烈的450~550 ℃温度区间的停留时间,从而减少了难酸洗相Fe₃O₄的含量,改善了盘条的酸洗性能。

Research on the reasons of difficult pickling of large-gauge 82B high carbon steel wire rod

In view of the problems that the phosphate film on the surface of the large-gauge φ10.0-φ16.0 mm 82B wire rod produced by JISCO was easy to fall off during the wire drawing process, the Fe₃O₄content in the oxide layer was relatively high and the drawing was difficult, the φ12.5 mm 82B wire rods produced by JISCO and Steel A were researched by SEM to observe thickness and structure composition of surface oxide layer, by EDS to analysis distribution of elements and by XRD to detect the types and proportions of phase of oxide layer. The results show that the surface of the wire rod produced by JISCO is rougher, and the oxide layer is alternately combined with canine teeth on the surface of the wire rod, the mass fraction of Fe₃O₄is 39.1% which higher than that of the wire rod of Steel A, and the CrSi₂ layer is also denser. Therefore, optimization measures were proposed for the production process. By reducing the laying temperature and increasing the cooling speed, the proportion of FeO of the easy-pickling phase can be increased, and the residence time at the temperature of 450-550 ℃ of the most intense eutectoid reaction can be reduced, thereby the content of Fe₃O₄ of hard-pickling phase is reduced, and the pickling performance of the wire rod is improved.