Study On Performance Of Plasma Sprayed WC-20Cr7Ni Coating On Continuous Casting Machine

In recent years,the continuous casting technology of slabs has been greatly developed and occupied an important position in the production of steel industry.The laminating roller is an important part of the continuous casting machine,and the working environment is very harsh.It needs slabs up to 1000°C.Scroll up.Under the cyclic heat cycle of the heat transfer of the slab and the cooling water inside the pulling roller,thermal stress is applied,and cracks appear on the surface of the roller body.At the same time,due to the certain clamping force of the sizing roller on the slab,friction is inevitable during the rolling process,and wear will occur in long-term service.In this paper,WC-20Cr7 Ni is sprayed on the tensioning roller by plasma spraying,so that the tungsten carbide coating is used as a protective layer to strengthen the surface properties of the tension roller,and the thermal stress value and oxidative corrosion of the tension roller during service are reduced.Wear,which increases the service life of the tension roller.In this paper,the material properties of hardness,bond strength and thermal insulation properties of WC-20Cr7 Ni sprayed were firstly tested.The hardness test indirectly proved that the wear resistance of tungsten carbide coating is extremely high,while the bond strength test indicates tungsten carbide.The reliability of the coating during service is high.Finally,the thermal insulation performance test shows that the tungsten carbide coating can reduce the thermal stress of the working of the tension roller.Secondly,a thermal shock test was designed for the tungsten carbide coated test piece.The performance of the tungsten carbide coating under thermal shock was investigated by means of unidirectional heating to high temperature and then water quenching.Experiments showed that WC-20Cr7 Ni was sprayed at 80 times of thermal shock performance.Still good.Then,the microstructure of the cross-section of the tungsten carbide coating before and after thermal shock was observed by metallographic microscope,and the failure mechanism was explored by comparison.Then,the finite element software ABAQUS was used to simulate the working environment of the tensioning roller.The difference between the stress field and thetemperature field of the conventional tensioning roller and the tungsten carbide coating roller was compared under the same working environment.The stress and temperature data,the simulation results show that WC-20Cr7 Ni spraying can effectively reduce the thermal stress of the pulling roller.Finally,using the appropriate life calculation model,the thermal fatigue life of the conventional tension roller and the WC-20Cr7 Ni spray roller is calculated.The calculation results show that the WC-20Cr7 Ni spray roller has a long service life.