Study Of Processing And Properties On The New Pattern Hot Work Die Steel

This paper introduces and analyzes the application of the new pattern die steel carefully in the world and the development of the newest theory and the advanced technology of designing and making die. At the same time, it analyzes the design of die structure, the choice of matter, forging technics, heat treatment technics, machining process technics, machining precision, burnish technics and the influence of the maintain act to life-span of die. New pattern hot work die steels (4Cr5MoSiV1, 4Cr2MoNi) have the refractory nature, thermoseing nature, wearable nature, cool and heat fatigure resistance. In addition, they have the better forging process capability, the wider quench temperature extension, lower excessive sensitivity and higher quench ability. Moreover, they can embody the merits of all kinds of key points of the forging die steels. Making reasonable technics parameter is the key to boost the quality of the die steels (4Cr5MoSiV1, 4Cr2MoNi), which can reduce the cost of conduction and create the efficient conductivity. Through analyzing the chemical component and all kinds of characters of the new pattern hot work die steels (4Cr5MoSiV1, 4Cr2MoNi), the beginning forging temperature should be 1060~1150 ℃and final forging temperature be 850 ℃, rapidly decreasing temperature from 850℃to 600 ℃, ash cooling at the 600 ℃, forging reduction is carried out and drawn out time after time, selecting the forging technics that forging grade is more than 4. After forging, it adopts high temperature spheroidal annealing technics (1040~1080 ℃). Quench adopts heating up and heat preservation (1040~1080 ℃), oil cooling to 500~550℃and adopts 350℃×2~3 hour-air cooling. Temper technics adopts double-tempering, finally adopts salt bath surface nitrizing treatment. The results show that the refactory nature, thermoseing nature and wearable nature of the die steel (4Cr5MoSiV1, 4Cr2MoNi) excels the nature of the steel (5CrMnMo, 5CrNiMo). Their average life-span is 0.58~3.67 times longer than common die steel. It is important to upgrade conduct efficiency and reduce cost and economize die material. Moreover, the new pattern die steels have the same technics in the course of warm-up, cooling maintenance of forging production, as the steel (5CrMnMo, 5CrNiMo), which take advantage of putting the technics in practice in a large scale.