Study On Laser Cladding Preparation Process Of H13 Steel Bionic Strengthening Layer

In this paper,the common H13 die steel in actual production is taken as the research object.After analysis,Stellite156 cobalt-based alloy powder with good high temperature resistance,strong oxidation resistance and high hardness is selected as the cladding material.Through laser cladding surface strengthening method,combined Bionic coupling structure,using ultrasonic assist and rare earth added auxiliary cladding means to modify and strengthen the surface of H13 steel.The purpose is to improve the hardness,wear resistance,thermal fatigue resistance and other properties of the H13 mold steel surface,thereby improving the surface performance of the H13 mold steel and increasing the service life of the mold.(1)In order to obtain a better range of process parameters for the bionic coupled sample experiment and reduce unnecessary experiments,for the cladding of S156 on the surface of H13 steel with Stellite156 cobalt-based alloy powder,the APDL command flow programming of ANSYS simulation software was used to simulate the cladding process through ANSYS software.The influence of different laser power,scanning speed and other process parameters on the temperature of the molten pool,the shape of the molten pool and the stress distribution of the cladding layer,a good set of experimental process parameters were obtained.The experimental verification is in good agreement with the simulation results.That is,the cladding effect is better when the laser power is 1200 W,the scanning speed is 2mm/s,and the powder feeding voltage is 12 V.(2)On the basis of obtaining good process parameters,in order to further improve the various properties of the cladding layer,an auxiliary means of ultrasonic vibration is introduced to optimize the process parameters of the bionic coupled sample.Ultrasonicassisted process tests were conducted to analyze the cladding morphology,number of pores,metallographic structure and hardness of the cladding layer.When the ultrasonic frequency is32 k Hz,the hardness of the cladding layer is significantly improved,the structure is relatively fine and uniform,the cladding layer has fewer defects,and the quality of the cladding layer is further improved.The highest value of the hardness is found through the hardness test of the cladding layer Reached 597 HV.(3)The effect of introducing Y2O3 content on the quality of the cladding layer was analyzed to analyze the morphology of the cladding layer,the number of pores,the metallographic structure and hardness of the cladding layer.When the content of Y2O3 in the cladding layer is 2.5%,the cladding structure is fine,the segregation of the components is significantly improved,and the pore defects are less.Although the hardness enhancement effect is not significant with ultrasonic assistance,it is compared with the cladding layer without Y2O3.,The hardness value still reached above 560 HV,significantly higher than H13 steel itself.(4)After comprehensive simulation and actual experiments combined with auxiliary cladding means to obtain the process parameters that meet the preparation of bionic coupling samples,the design and preparation of the bionic coupling structure were carried out.Combined with the shell nacre structure,a multi-layer bionic structure suitable for H13 steel surface strengthening was obtained through calculation and analysis.The thermal fatigue test of the prepared bionic coupled specimens found that the thermal fatigue resistance of the cladding layer was significantly improved compared to H13 steel,the thermal fatigue level was significantly improved,and the thermal fatigue level was increased from 7 to 1.Through the experimental test of the wear resistance of the bionic coupling sample,it is found that the wear resistance of the bionic coupling sample is significantly improved,and the wear amount in the same time decreases from 0.097 g to 0.022 g.Compared with H13 steel,the wear resistance is improved by more than 3 times,and the maximum hardness value is 690 HV,the improvement effect is obvious.The Stellite156 cobalt-based bionic coupling sample prepared using the optimized processing technology has a better surface performance improvement than the H13 steel itself,which can increase the application range and service life of the H13 steel,and has certain application and promotion value.