卷取机夹送辊表面堆焊层组织性能研究

采用埋弧堆焊工艺在Q235B表面堆焊8-10mm的Cr8系列新型熔覆材料,测定其耐磨性和硬度变化,分析熔覆金属的组织形貌和高温工况下的合金元素扩散。研究结果表明,熔覆金属打底层主要是以铁素体为主,伴随着少量的贝氏体。盖面层的焊态组织主要为马氏体和残余奥氏体,伴有少量的回火马氏体,同时在枝晶马氏体间可见少量较小的碳化物。经550℃回火后其盖面层组织为回火马氏体和残余奥氏体,碳化物析出相均布较焊态呈增多趋势。焊态硬度值为530-580HV300,回火后硬度值为720-830HV300,磨损失重是45#淬火钢的0.31倍。在使用3个月后发现在熔覆层表面出现了元素偏移并形成了由Cr2O3、WO等组成的氧化膜,降低了夹送辊的粘钢倾向,提高使用寿命。

Study on Microstructure and Properties of Surfacing Build-up Welding Layer for Coiler Pinch Roll

In this paper,8-10 mm thickness Cr8 series of new cladding materials was deposited on the surface of Q235 B by submerged arc welding technology.The wear resistance and hardness were measured.The microstructures of cladding metal and the migration elements in high temperature condition were analyzed.The results showed that the microstructure of bottom layer were ferrite and small amount of bainite.The cover layer was mainly martensite and retained austenite with a small amount of tempered martensite,and little carbide can be seen in dendrite martensite.After tempering at 550℃,the microstructure of surface layer was tempered martensite and residual austenite.The distribution of carbide precipitates was more uniform than welded layer.The hardness of welding was 530-580 HV300,and 720-830 HV300 after temper.The wear loss was 0.31 times than 45 steel.It can be found elements deviation and the Cr2 O3、WO oxide appeared on the surface of cladding layer after using 3 months,which reduced the steel sticking tendency of pinch roll and improved its service life.