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为研究硬质合金与碳钢焊条电弧焊连接的可行性,本文选取低碳钢焊条J422、铸铁焊条Z308和Z408对WC-10Co-20Ni硬质合金与45号钢进行焊条电弧焊连接,通过微观组织分析、X-射线衍射物相分析、硬度分布测试及弯曲强度测试等手段,对比分析了3种焊条所焊接头的组织与性能,研究结果表明:采用J422焊条焊接后,焊缝组织以马氏体和共晶碳化物为主,并含有η碳化物层,接头结合强度弱,不适于焊接硬质合金;Z308和Z408焊条可以抑制界面η碳化物层的生成,但在焊缝中有大量夹渣,影响接头性能;Z408焊条焊缝有少量的共晶碳化物产生,但因熔敷金属的膨胀系数介于硬质合金与钢之间,能有效缓解焊接应力,较适合用于硬质合金的焊接。使用Z408焊条焊接时,采取适当提高电流,增加摆动频率等工艺措施,可以减少夹渣的数量和分布状态,促进成分和组织均匀化,有利于提高接头性能,弯曲强度可以达到WC-10Co-20Ni硬质合金母材强度的90%以上。
In order to study the feasibility of arc welding connection between cemented carbide and carbon steel electrode, this paper selected low-carbon steel electrode J422, cast iron electrode Z308 and Z408 electrode arc welding of WC-10Co-20Ni cemented carbide and 45 steel, Tissue analysis, X-ray diffraction phase analysis, hardness distribution test and flexural strength test were used to analyze the microstructure and properties of the welded joints of the three kinds of welding electrodes. The results show that after the welding with J422 welding rod, Martensite and eutectic carbide, and contains η carbide layer, the joint bond strength is weak, not suitable for welding cemented carbide; Z308 and Z408 electrode can inhibit the formation of the interface η carbide layer, but there are a lot of weld Slag inclusions, affecting joint performance; Z408 electrode weld a small amount of eutectic carbide, but due to the expansion coefficient of the deposited metal between the carbide and the steel, can effectively ease the welding stress, more suitable for hard Alloy welding. When welding with Z408 electrode, proper measures such as increasing current and increasing wobble frequency are adopted to reduce the amount and distribution of slag inclusions, promote the homogenization of components and tissues, and improve the joint performance. The flexural strength can reach WC-10Co-20Ni Carbide base metal strength of more than 90%.