偶发性堆钢下热轧线材内部质量特征分析

ANALYSIS OF INTERNAL QUALITY CHARACTERISTICS OF HOT ROLLED WIRE ROD UNDER OCCASIONAL STACKING

热轧带肋钢筋是颇具代表性的建筑领域用线材,然而在冶炼过程中偶发性的堆钢事故制约了热轧带肋钢筋的高效生产。因此,企业急需从堆钢样品的质量特征中总结经验。通过在堆钢现场取中轧试样和精轧试样,结合金相、ASPEX自动扫描电镜、小样电解和场发射扫描电镜分析,重点从夹杂物的角度对堆钢下热轧带肋钢筋的内部质量进行研究。ASPEX自动扫描电镜分析结果显示,非金属夹杂物在中间样和成品样中均主要为Al_(2)O_(3)-SiO_(2)类和MnS类,10μm以下夹杂物以MnS类为主,40μm以上夹杂物以Al_(2)O_(3)-SiO_(2)类为主。金相分析显示,中间样和成品样中的夹杂物形貌多样,以条带状、点状、不规则块状和三角状形貌特征为主,并均可观察到内部有明显裂纹缺陷,且成品样中可观察到钢中出现“异相”不溶物。小样电解和FESEM扫描电镜分析显示,中间样和成品样中能观察到夹杂物为单体氧化物、复合氧化物和硫化物3种类型,复合氧化物呈现尺寸层级全覆盖,成品样中CaO-Al_(2)O_(3)-SiO_(2)系复合氧化物表现出一定的基体“附着性”。

The hot-rolled ribbed bar is a typical wire rod used in construction field.However,occasional stacking accident in smelting process restricts the efficient production of hot-rolled ribbed bar.Therefore,it is urgent for enterprises to sum up experience from the quality characteristics of steel samples.By taking the samples of intermediate rolling and finishing rolling at stacking site,combining with metallography,ASPEX,sample electrolysis and field emission scanning electron microscopy,the internal quality of hot-rolled ribbed bar under pile-up was studied from the point of inclusion.The results of ASPEX SEM showed that the non-metallic inclusions in the intermediate and finished samples were mainly Al_(2)O_(3)-SiO_(2)and MnS.The inclusions below 10μm were mainly MnS,and the inclusions above 40μm were mainly Al_(2)O_(3)-SiO_(2).The metallographic analysis shows that the inclusions in the middle sample and the finished sample are of various morphologies,and the main features are strip,Dot,irregular block and triangle,the"Different phase"insoluble matter can be observed in the finished product.The results of sample electrolysis and FESEM showed that the inclusions in the intermediate and finished samples were monomeric oxides,complex oxides and sulfides,the composite oxides of CaO-Al_(2)O_(3)-SiO_(2)exhibitsomematrixadhesion.