Improve The Die-casting Mold Steel H13 Life

In our country, H13 die steel is widely used as Al alloy die material and two of the major reasons for die failure are soldering and thermal fatigue. Therefore, the two key factors, soldering and thermal fatigue, decide the service life of H13 die casting die.The experiment of hot dip aluminizing had been carried out in order to study the interaction between die casting die and aluminum alloy as well as how Si affects the soldering tendency in die and aluminum alloy casting. The experimental results show that the existence of Si decreases the activity coefficient of Al in the phase of Fe-Si-Al and prevents aluminum atoms from moving molten Al to the steel substrate. As a result, Si reduces the interaction between die steel and molten aluminum alloy and then effectively impedes the soldering tendency of aluminum die casting.The experiment of hot dip aluminizing had been done in order to study the formation and dissolution of the intermetallic layer between die casting die and aluminum alloy. The experimental results reveal that the formation and dissolution of intermetallic phases is a cyclic process. The relationship between formation and dissolution of intermetallic layer results in weight loss and volumetric loss of the die steel substrate.The experiment of HSVM, DSC and mechanics properties had been performed to study the effect of different Si addition on the anti-thermal fatigue property of H13 steel. The results tell us that the net of casting carbide tends to be broken up, the Y grain grows up and strength declines with the increase of Si addition. The K/Na, Mo multiple modification can eliminate the side effect of Si obviously. And the H13 steel has good mechanics property with the 0.5% Si addition and modification by K/Na, Mo.The influence of quenching temperature on the properties of H13 steel transformed by Si and K/Na,Mo had also been studied. The thermal fatigue property of this steel increases with the increase of quenching temperature. It is very useful to prolong theservice life of hot-working die made of H13 steel transformed by Si and K/Na,Mo.