Study On Mechanical Properties And Microstructure Of Transition Layer By Surfacing On ZG35MnSi

As surfacing is simple in technique and economic in equipment, it is widely usedto repair or manufacture in many industries fields. Surfacing on the cast steel to makeforging dies have a more broad development space and the stage, especially in the lagerforging dies owing to its obvious technical and economical advantages over othermethods.Surfacing on the cast steel to make forging dies can combine the excellent wearresistance of the cladding layer and the low cost of the cast steel. While the greatdifference of physical and chemical properties between the cast steel and the claddinglayer can easily result in the weld dilution and some cracks, which heavily influencedthe service performance of this kind of mould, so it is difficult to get a good integrationof the cast steel and the cladding layer during surfacing.Generally, a transition layer is adopted between the cast steel and the claddinglayer, thus surfacing procedure of these materials includes three steps: firstly, weldingfor the transition layer on the cast steel, then for the cladding layer on the transitionlayer. The surfacing welding experiment on cast steel ZG35MnSi developed byChongqing JieXin Die&Mould Inc.ltd has been carried out with cladding layerRMD248widely used in market. This paper will study three kinds of transition layermaterial (RMD136, RMD535, and RMD142) cast steel ZG35MnSi and the performanceof surfacing.In the surfacing technique “cast steel+cladding layer”, the research focused on thecast steel-the cladding layer interface. In the surfacing technique “cast steel+transitionlayer+cladding layer”, the transition layer can be divided into three regions: cast steel-transition layer interface, transition layer-cladding layer interface and transition layer.Research emphasis on this material is placed on the surfacing technology control andperformance test of the transition layer, in which the microstructure, phase structureconstitution and chemical composition variation are analyzed in detail. In addition, thesurfacing bonding strength was evaluated on mechanical properties.In this paper，three kinds of transition layer of different chemical composition andmechanical properties have been studied, especially the welding performance. Theeffects of three kinds of transition layer after surfacing were investigated by opticalmicroscope, scanning electron microscope test, energy spectrum analysis, hardness test and tensile test. Carbon migration, the carbon migrates from the cast steel ZG35MnSi tocladding layer side, is obvious in annealing state. Energy spectrum analysis shows thatall transition layers can promote chemical composition uniform transition andTransition layer RMD136and RMD535can prevent carbon migration effectively. Thebest transition layer, RMD136, is selected by comparing the three kind of transitionlayer’s overall performance. The results showed that the transition layer RMD136canefficiently prevent from arising of cracks and hardness gradient distribution is satisfied.In a word, the transition layer can improve the interfacial microstructure; preventfrom arising of cracks. The results show that cast steel, transition layer and claddinglayer can obtain the high quality joint among each other. Cast steel ZG35MnSi,transition layer RMD136and cladding layerRMD248can be successfully welded undersuch experiment conditions. The research work of this paper has the vital significanceon repairing or manufacturing the forging dies with cast steel as base metal and providetheoretical basis for the practical production.