Research On Thermal Fatigue And Wear Properties Of H13 Steel Processed By Bionic Laser Process

Nowadays, H13 steel has been widely used in aluminum die-casting molds, but because of the thermal wear and thermal fatigue crack during die casting process, the production efficiency is affected. As a new surface strengthening process, biomimetic coupled laser remelting(BCLR) process is putted in an important position all over the world.In this paper, wear properties and thermal fatigue properties of H13 steel was studied by experiment. In order to improve the production efficiency, more effective strengthening models and methods were proposed by comparing different biomimetic models and laser surface strengthening methods.In this paper, different test methods were selected to investigate the effects of BCLR process on wear properties and thermal fatigue properties of H13 steels. In order to investigate the effects of BCLR process on wear properties of H13 steels, linear-shape biomimetic specimens with different effective remelting surface ratio were obtained by laser surface melting on H13 steel surface in 600? conditions. The microstructures of laser melting zone and the effects of biomimetic units on wear properties of H13 steels were analyzed. The wear mechanism of H13 steel was investigated. The results indicated that the higher effective remelting surface ratio has, the better wear resistance it has got, but the growth is leveling off. At last, an attempt to harden the working surface of die-casting dies with biomimetic units was made by using biomimetic coupled laser welding with filler wire process and laser remelting process with linear-shape and the grid-shape biomimetic model, respectively, the test method is thermal fatigue test of aluminum medium. The test data were recorded during the thermal fatigue cycling test and 5000 cycles for 500 cycles intervals. The results were statistically analyzed. The the propagation of thermal fatigue crack under different treatments was analyzed. The results indicated that the microhardness of biomimetic units that was made by laser welding with filler wire is slightly above the biomimetic units that was made by laser remelting process, samples that is processed by laser welding with filler wire have better thermal fatigue resistance ability, the effect of grid-shape biomimetic model is better than linearshape. At last, using laser welding with filler wire process to strengthen the mold, and the results shows that the service life of die-casting die that is strengthened by laser welding with filler wire process is doubled.