搪瓷钢焊缝处瓷釉层凹坑缺陷形成原因分析

Cause analysis of pit defect formation in weld seam enamel layer of enamel steel

针对冷轧搪瓷钢板在生产热水器内胆成形过程中在焊缝附近出现的圆形缺陷,采用光学显微镜、扫描电镜和能谱仪等对该缺陷的微特征、形成原因进行了系统分析研究。详细阐述了该种缺陷在金相显微镜及扫描电镜下的微观形貌及元素分布特征,对搪瓷板界面和基板的金相显微形貌进行了详细分析。结果表明,该种缺陷的形成是由于焊缝附近表面凹凸不平,气体在液相表面张力的作用下在表面下凹处集中,在焊缝处极易出现尺寸较大的气泡。通过采取适当措施消除焊缝处及其附近表面的凹凸不平,增加其连贯性,减少了气泡坑缺陷的形成。

In the production process of water heater container by cold rolled enamel steel,some circular defects were found in the vicinity of weld seam. The macroscopic characteristics and forming reason of these defects were systematically analyzed using optical microscopy,scanning electron microscopy and energy dispersive spectroscopy. The microstructure and elemental distribution of defects were investigated under metallographic microscope and scanning electron microscopy. The metallographic microstructure of enamel plate interface and substrate were analyzed in detail. The results showed that the formation of defects were mainly due to uneven surface near the weld. The gas was concentrated on the surface recess under the effect of surface tension of liquid phase,and larger bubbles were easily formed near the weld. By taking appropriate measures to eliminate irregularity near the welding seam to increase the coherence,the formation of bubble pit defects were reduced.