Development Of Wear-resistant Resurfacing Welding Wire For Mill Roller

In this study,a new cored wire which used mild steel band as sheath material,graphite，ferrochromium with high carbon,Cr3C2,MoFe,NbFe,TiC as cores was prepared. Four kindsof Fe-Cr-C hardfacing alloy which were suitable for coal mill repairing were prepared onthe Q235steel. The four kinds of Fe-Cr-C hardfacing alloy were marked1、2、3、4. It hadbeen compared the four kinds of Fe-Cr-C hardfacing alloy with the overlay cladding(0marked) that was prepared using commercial wire for welding. Hardness，sliding wear test，high temperature oxidation property had been tested. The microstructure, carbide structure,surface morphology after wear, oxidation layer structure had been researched by OM,Scanning Electron Microscopy(SEM), Energy Dispersive Spectrometer (EDS), X-rayDiffractometer(XRD),etal.The results showed that the main phases in speciment included the primary carbide(Fe,Cr)7C3, Martensite and retained austenite. The amount of primary carbide (Fe,Cr)7C3decreased and the size increased from4、3、1、2to0. The Five kinds of Fe-Cr-C hardfacingalloy showed high hardness and the HRC hardmess of overlay cladding that was marked0was up to62.After sliding wear test，the results showed that under100N and200r/min,the weightloss of0、1、2、3、4overlay cladding was0.0111g、0.0112g、0.0114g、0.0086g、0.0067gafter one hour. The wear mechanism of overlay cladding included Micro-cutting、Micro-grooves,Micro-crack. Under the same speed of rotation, weight loss of overlaycladding increased with load,but the relation between weight loss and load was not linear.Under the same load, weight loss of overlay cladding increased with speed of rotation. Thewear mechanism of overlay cladding was transformated from abrasive wear to oxidativewear、adhesive wear and abrasive wear, although the main wear mechanism was abrasivewear.After100hour oxidation at800℃,five kinds of overlay cladding expressed hightemperature oxidation resistance. The high temperature oxidation resistance of0、1、2、3、4overlay cladding was5times、6times、8times、9times、10times than Q235steel. Themain phase on surface was Cr203and Fe2O3. For4marked,oxidation film which was theshape of spinelle and compact、 unbroken included more Cr;Different from themicrostructure of4marked,the oxidation film of3marked which contained less Cr had more gap. The oxidation film for overlay cladding of0、1、2marked which had more ironoxides was loosened.Compaired with five kinds of overlay cladding,4marked had best effect on microstruct-ure、hardness、wear-resistent and high temperature oxidation resistance.