Study On Repair Performance Of Die - Casting Mold Material Laser Filling

Die-casting is a kind of non-cutting forming method of metal hot working with high benefit and high efficiency. In recent years, die-casting dies has been widely used in automobile, instruments and meters, air navigation, motor manufacturing, daily hardware and other industries. Working principle of die casting production lead to the die casting work under harsh environment, the die cavity surface is easy to wear and thermal fatigue cracks cause die invalidation, causing a serious waste of resources and money. So, how to use in production is a simple and effective way for the damage to the die repair has become a problem concerned by enterprises.In order to solve the problem of cracks on die-casting dies, the method of combining laser technology and bionic technology was used to repair them. Repairing layer on die-casting dies was prepared utilizing the method of laser wire filling welding.Firstly, the relationship between defocus amount and variable of recovered layer were investigated in the case of other parameters unchanged. Secondly, the relationship between electric current and variable of recovered layer discussed were in the case of other parameters unchanged. Then the recovered layer morphology and size were discussed under the condition of different wire diameter. Then researched under the condition of other parameters unchanged, wire speed to repair the layer forming size and surface quality of weld. Finally, the optimal process parameters for laser wire filling welding were concluded. These parameters were that the current was 180 A, the defocusing amount was-10 mm, and the wire filling speed was 0.032 m/min.The optimal parameters were used to repair the failure die, the thermal properties of die and actual working conditions were mainly studied. In order to analysis the thermal fatigue resistance, the thermal fatigue test was executed. The laser melting specimen, the laser welding with filled wire specimen and the untreated specimen were test in the thermal fatigue testing machine. The thermal fatigue test parameters were heating 3s and cooling 4.5s for a cycle, each specimen cycle 5000 times, and crack morphology were observed and recorded every a certain cycle number. It was concluded through summarizing analysis all specimens crack extension form and length that thermal crack initiation was effectively inhibited, thermal fatigue crack extension was delayed, and the thermal fatigue resistances of die-casting dies were enhanced through the method of laser wiring with filled wire. The results were concluded through the actual life test of the die that the service life of damaged die was effectively extended. The production cost for enterprises were reduced and the resources were saved.