Study On Microstructure、Properties And Surface Strengthening Of Copper Alloy Of Horizontal Continuous Mould

At present, horizontal continuous casting is the advanced method which modern steelplant produce billet and cast steel materials.Copper alloy mould is the most critical andconsumable component of the horizontal continuous casting equipment.Due to theextremely harsh environment of the copper alloy mould, the surface of copper alloy mouldoften have scratches, wear, spalling and thermal crack.In order to improve the performanceof copper alloy mould, copper mould should be researched so that it can be maintained at ahigh temperature,high hardness,high wear resistance,good thermal conductivity.In this paper,by tensile testing machine,durometer, friction and wear tester, scanningelectron microscopy （SEM）, energy dispersive spectrometer（EDS） and so on, reserched onCuCo₂Be alloy’s heat treatment process, arc spraying process on the surface of the alloy,the friction and wear properties of sprayed coatings. The results show that:By950℃×1.5h solution+460℃×1.5h aging, at room temperature the CuCo₂Be gettinga better performance,alloy’s brinell hardness is254HBS, and the conductivity of CuCo₂Bealloy is47.24%IACS,the tensile strength of CuCo₂Be alloy is880.56MPa, the elongationrate of of CuCo₂Be alloy is16.16%, the fracture mechanism of CuCo₂Be alloy is ductilefracture.The optimal process of the CuCo₂Be alloy alloy surface arc spraying: using Cr₂C₃/Fespraying material，spraying voltage is35V, the current is140A, spraying distance is150mm, spraying air pressure is0.7MPa, the bonding strength of the coating and thesubstrate is30.5MPa, the microhardness of coating is992.75HV. The thermal shockresistance of the arc sprayed coatings have larger diference at different process parameters,thermal shock performance of coating which are sprayed by the lower spray voltage andlow current spraying is better.Tested copper alloy mould was on machine for lifeassessment.Friction and wear mechanisms of Cr₂C₃/Fe coating at room temperature are abrasivewear, adhesive wear and fatigue wear.When coatings was rubbed in high temperature,theadhesive wear and fatigue wear were observed. The high-temperature friction and wearmechanisms of the copper substrate is typical adhesive wear. High temperature wearresistance of Cr₂C₃/Fe coating of is much higher than the copper matrix. When load is15N,the friction velocity is50r/min,friction time is0.5h, the wear scar depth of the CuCo₂Be alloy substrate which isn’t sprayed is about eight times as deep as that of the coating.