The Research Of Laser Cladding Layer’s Size Effect Under The Thermal Shock Condition

In this paper,the influence of the size change of the cladding layer on the thermal shock resistance of the continuous casting roll was studied,by using the advanced material surface modification technology-laser cladding.The continuous cast rollers is one of the core components of casting equipment and its important role is to transport the hot slab,while the cool water brings down the fever.So the rollers work in a high-low temperature cycle change condition,and the surface of rollers will be failure by the impacted of large temperature difference.The continuous casting machines are equipped plenty of rollers,of which quality will decide the equipment’s working life.In the paper,the Fe60 alloy cladding layer,which is widely used to repair wearing continuous casting rollers’ surface,was selected as a research object,and its high hardness would generate thermal fatigue cracks under the large thermal changing shock.There are three parts in the paper,which are theoretical analysis,numerical simulation and experimentation,researching the relationship between thermal shock resistance and the different size of cladding layer,and obtain reasonable process parameters,to improve the quality and working life of the remanufactured casting roll.The main content included:According to the theory of heat transfer and the theory of thermal stress,the mechanism of heat transfer in the continuous casting roller and the material of thermal stability are explored,and the thermal balance model is established.The law of cracks distribution and extension is analyzed under the effect of thermal stress.Based on heat balance model of continuous rollers and using the Abaqus software,the roller’s temperature field distribution is computed and the stress field is obtained by the thermal-force coupling.Compared the effect of the change of cladding layer thickness to temperature filed and stress field.The cladding layer test specimens with 1mm,2mm,3mm and 4mm different size are prepared on the 35 CrMo steel plates,and their performances of thermal shock resistance are compared by the thermal shock test.Then,the macro and micro performance of different laser cladding layers are analyzed,which used the micro-hardness test,the friction and wear test and the metallographic microscopic test.Finally,integrated all kind of test’s results,the better size parameters of the cladding layer are determined,that provided technical guidance for the remanufacture of continuous casting rollers.