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利用金相、扫描电镜观察及电子探针(EPMA)面分析技术等研究了合金元素(Si、Mn、Ni、Cr)对焊丝钢盘条氧化皮显微结构的影响,并采用拉伸试验及酸洗试验评价氧化皮的剥离性.结果表明,Si、Ni和Cr元素对氧化皮显微结构的影响大于Mn元素;低碳钢的氧化皮主要为Fe的氧化物,其最内层和中间层的氧化物均以柱状晶形式垂直基体向外生长;在低碳钢基础上增加Si含量,可显著降低氧化皮总厚度,氧化皮最内层为富Si层,且氧化皮/基体界面的凹凸度增加;进一步增加Ni含量,最内层的合金富集层以锚状沿晶界向基体内延伸.降低氧化皮/基体界面凹凸度、减少合金富集层均利于氧化皮剥离,机械法对界面凹凸度更敏感,而酸洗法对氧化皮缺陷数量较敏感.

The effect of alloy element such as Si,Mn,Ni and Cr on the microstructure of oxide scale on the welding wire steel was studied by metallographic analysis,scanning electron microscope(SEM) analysis and electron probe microanalyzer(EPMA) mapping analysis,and the descaling property of oxide scale was evaluated by tensile test and pickling test.The results show:the effect of Si,Ni and Cr on the microstructure of oxide scale is much greater than that of Mn,and the oxide scale on low carbon steel is constructed of iron oxides,which shows that the oxides in the innermost and middle layer appear to have grown vertically from the substrate as columnar grains.Moreover,the increase in Si content in low carbon steel leads to a notable decrease in total thickness of oxide scale and an increase in uneven scale/steel interface accompanied with a Si-rich layer in the innermost oxide scale.And in this case further increase in Ni content leads to an innermost layer riched in alloy element,and oxidic pegs are found penetrating the grain boundaries of the steel.Decreasing the unevenness of scale/steel interface and enrichment of alloy elements in inner layer are beneficial for descaling property,and mechanical descaling is more sensitive to the unevenness of scale/steel interface,while acid pickling descaling is more sensitive to the number of oxide defects.