Si元素对明弧堆焊奥氏体合金组织及耐磨性的影响

为获得以奥氏体为基体且韧性及耐磨性良好的明弧堆焊合金,采用药芯焊丝自保护明弧焊方法制备了以奥氏体为基体的Fe-C-Mn-Cr-Nb-V-Ti系多元耐磨合金,借助X射线衍射仪、扫描电镜及其附属能谱仪等测试手段,研究了Si含量对其组织和耐磨性的影响。结果表明:堆焊合金基体为γ-Fe,硬质相有(Fe,Cr,Mn,V)_(23)C_6,(Nb,Ti)C和(Fe,Cr)_3(C,B)等;当堆焊合金含1.5%Si(质量分数)时,出现了沿晶(Fe,Cr,Mn,V)_7C_3相;随着Si含量提高,沿晶界分布的(Fe,Cr,Mn,V)_(23)C_6型碳化物数量先增加然后减少,形态从树枝骨架状变为层片状离散孤立分布,胞状γ-Fe晶内原位析出的(Nb,Ti,V)C复合碳化物随之增大,堆焊合金耐磨性呈先提高后下降再提高的趋势;0.9%Si和1.5%Si堆焊合金试样的磨损质量损失低于一般高铬铸铁,具有良好的耐磨性和韧性,其磨损机制主要为磨粒的显微切削。

Effect of Silicon Element on Microstructure and Abrasion Resistance of Open Arc Hardfacing Austenitic Matrix Alloys

Fe-C-Mn-Cr-Nb-V-Ti system complex ausentitic matirx wear-resistant alloys were deposited by the method of flux-cored wire selfshielded open arc welding,and the effects of silicon content on the microstructure and abrasion resistance of obtained alloys were investigated by X-ray diffractometer (XRD),scanning electron microscopy (SEM) as well as energy dispersive spectrometer (EDS).Results showed that the matrix of alloy was γ-Fe phase,and their hard phases consisted of (Fe,Cr,Mn,V) 23 C6,(Nb,Ti) C,(Fe,Cr)3 (C,B),etc.When the Si content was 1.5％(mass fraction),(Fe,Cr,Mn,V)7C3 phase appeared in alloys.With the increase of silicon content,the volume fraction of intragranular (Fe,Cr,Mn,V)23 C6 carbide firstly increased and then fall down,and their shape transformed from dendritic skeletal-like into isolated discrete flake-like.At the same time,the (Nb,Ti,V)C phases in situ precipitated from cellular γ-Fe became more coarse,and the wear resistance firstly increased,then decreased and finally increased again.Furthermore,the hardfacing alloys with 0.9％ Si and 1.5％Si possessed lower wear mass loss,and more excellent abrasion resistance and toughness than high-chromium cast irons,and their dominant wear mechanism was micro-cutting of abrasive particles.