电弧重熔对工业390A合金显微组织、力学性能和摩擦学性能的影响

Effect of arc re-melting on microstructure,mechanical and tribological properties of commercial 390A alloy

为研究电弧重熔对390A合金显微组织、力学性能和摩擦学性能的影响,对采用常规感应熔炼法制备的390A合金锭进行电弧重熔。采用光学显微镜和扫描电镜观察合金的显微组织,采用布氏硬度法和拉伸试验测试合金的力学性能,采用球对盘式摩擦磨损试验机对摩擦学性能进行研究。结果表明,感应熔炼和电弧重熔的390A合金中均含有α(Al)、Al-12Si共晶相、初生Si颗粒、θ-CuAl_(2)、β-Al_(5)FeSi、δ-Al_(4)FeSi_(2)和α-Al_(15)(FeMnCu)3Si_(2)相。电弧重熔使这些相的晶粒细化,α(Al)相与初生硅颗粒分散更加均匀,初生硅颗粒的棱角变圆。与感应熔炼样品相比,电弧重熔后390A合金的硬度由102 HB提高到118 HB,抗拉强度由130 MPa提高到240 MPa。电弧重熔工艺也使390A合金的耐磨性提高,摩擦因数降低。

To investigate the effect of the arc re-melting on the microstructure,mechanical and tribological properties of the 390 A alloy,its ingot produced by the conventional induction melting method was subjected to the arc re-melting process.The microstructure of the 390 A alloy was examined by OM and SEM.Mechanical properties of the 390 A alloy were determined by the Brinell method and tensile tests.Tribological properties were investigated with a ball-on-disc type tester.It was observed that the microstructure of both conventional induction melted and arc re-melted 390 A alloys consisted ofα(Al),eutectic Al-12 Si,primary silicon particles,θ-CuAl_(2),β-Al_(5) FeSi,δ-Al_(4) FeSi_(2),andα-Al_(15)(FeMnCu)3 Si_(2) phases.Re-melting with the arc process caused grain refinement in these phases.In addition,after this process,theα(Al)phase and primary silicon particles were dispersed more uniformly,and sharp edges of primary silicon particles became round.The arc re-melting process resulted in an increase in the hardness of the 390 A alloy produced by the conventional method from 102 HB to 118 HB and the tensile strength from 130 to 240 MPa.It also caused an increase in the wear resistance of the 390 A alloy and a decrease in the friction coefficient.