规格φ5.5 mm的ER50-6热轧盘条拉拔至φ2.2 mm时出现了断丝现象, 断丝部位附近存在较多的表面裂纹。通过金相检验和扫描电镜微区分析等方法对拉拔断裂的原因进行了分析。结果表明: 连铸坯皮下卷渣造成盘条表面局部增碳, 增碳区珠光体含量较基体明显偏高, 塑性、韧性下降, 拉拔时沿增碳区发生断裂。

ER50-6 hot-rolled wire rod was fractured when drawing from φ5.5 mm to φ2.2 mm, there were much cracks near the fracture position. The reason of drawing fracture was analyzed by means of metallographic examination and micro-area analysis by scanning electron microscopy. The results showed that local carburetion had caused by slag entrapment defect of continuous casting billet, and the pearlite was obvious higher than matrix, the plasticity and toughness were reduced. At last it was fractured alone the carburetion area in the process of drawing.