硬脂酸微波反应制备焊条抗吸潮保护膜

Preparation of water-resistant electrode coating with stearic acid by microwave reaction

碱性焊条容易因吸潮而引起焊缝扩散氢增加,采用在焊条表面进行微波反应的方法制备了抗吸潮保护膜.将烘干的焊条放入溶有一定量硬脂酸和Fe3O4粉末的石油醚溶液中,取出后进行微波反应,使焊条表面具有抗吸潮性能.用红外光谱仪和扫描电镜对焊条保护膜的成分和形貌进行了分析,并进行了熔敷金属扩散氢测试.结果表明,Fe3O4能融化硬脂酸并使其与焊条表层反应,形成的保护膜在焊条表面结合牢固,能有效阻隔水分进入焊条内部.Fe3O4粉末在焊接过程中进入电弧空间强化气氛的氧化性,提高电弧气氛的去氢能力.焊条保存0~8 h其扩散氢含量基本无变化,为未经表面处理焊条扩散氢含量的70%.

Absorbing moisture of electrode coating may easily lead to high diffusible hydrogen of weld metal,resulting in hydrogen embrittlement,blowhole,cold crack and other defects.Electrode was immersed to the petroleum ether solution containing stearic and Fe3O4 powder,after that electrode was treated by the microwave oven and then became water-resistant.Microwave absorption material Fe3O4 was used to reduce the diffusible hydrogen of weld bead,and promote the reaction of stearic acid and electrode surface.The results of FT-IR and SEM microscope indicate that Fe3O4 absorbs microwave and melt stearic acid to form the water-resistant film.The diffusible hydrogen of the deposited metal of microwave treated electrode decreased to 70% of the one made by the untreated electrode,and such property does not vary very much as the the stoving time keeping 8 h.