Effect Of Laser Quenching On The Properties And The Microstructure Of Die Casting Die Steel

In recent years,with the rapid development of the automotive industry,the mold industry has entered a new era.At the same time,a higher standard of the comprehensive property of the mold is needed.And the life of dies has an important influence on the enterprises' production efficiency,products quality and the production costs.The phenomenon of the melting loss occurs after working a period of time and it results the damage of the surface.During the process of the Aluminum alloy die casting,dies which are made of hot working die steel will get exposed by the liquid aluminum alloy.It will result defects in the surface of the die steel,such as the erosion and thermal cracks and the reduction of the surface roughness and the poor dimensional accuracy of machined parts.In order to avoid these defects,surface modification treatment such as induction hardening,electro/electroless deposition,physical/chemical vapor deposition,plasma nitriding and lubricating oil,which is used for improving the wear and corrosion resistance of steel.Since the advent of the laser technology,more and more attention has been focused on the development of the laser quenching,laser cutting,laser hardening and so on.Laser technology has become a trend of advanced manufacturing technology.Laser processing technology has more advantages than traditional processing in processing quality,processing efficiency and economy.Laser quenching is a kind of the most important laser processing technology.The high density of laser scanning on the surface of the die steel and the temperature rises sharply forming austenite.After rapid cooling,the microstructure has transformed into fine martensite.Laser treatment on the surface of die steel can effectively improve the strength and hardness of the component,it can also enhance the performance of the abrasion and corrosion resistance.The hardness of the laser treated surface is higher than that of the common quenching.The microstructure of the laser treated zone is much finer.The Thermo-calc software was applied to calculate the phase diagram of EX1 hot-working die steel and the laser quenching process was designed according to the phase diagram.The surface of EX1 die steel was processed by laser quenching.After laser quenching treatment and aluminum alloy melt loss experiment,the microstructure was investigated systematically by scanning electron microscope.The mechanical property of laser quenching on EX1 die steel was analyzed.The results show that the microstructure after laser quenching treatment is martensite.Laser quenching can significantly improve the surface smoothness of EX1 die steel and enhance the resistance to melting loss and friction and wear properties.The hardness of the melted zone is higher than that of the heat affected zone and the hardness of the base metal.The main purpose of this paper is to study the effects of the microstructures in laser quenching on mechanical properties.