Age Hardening Mold Steel for Plastic Die Steel
Age hardening plastic die steel. Hardened section steel meets the requirements of die performance, but it also brings difficulties in heat treatment. The special change is heat treatment deformation. Even if micro-deformed steel is used, the crowns will be deformed, which leads to difficulties in cutting, and the cost will be increased and the life cycle will be prolonged by correcting the deformation. Mold makers do not welcome this type of steel. Moreover, plastic moulds are larger and more precise. Because of the fierce market competition, rapid product renewal, or the use of mould renovation, this repair process requires good weldability of steel. It is more inappropriate to change the carbon content of the hardened section steel to improve the hardenability of the steel. Age hardening steel can solve this problem well. Age hardening steel market adds alloying elements other than carbon and dissolves and precipitates them to improve hardness. That is, through solid solution treatment and effective treatment.
MARTENSITIC AGING STEEL.
This kind of steel has very high strength and hardness, good workability and weldability, heat treatment process (heat treatment process is simple, and nitriding can further improve hardness and wear resistance), cold plastic deformation formability is also good. Especially outstanding is the high temperature strength and hardness. Originally, this kind of steel was used in aerospace industry. It can be used not only for making plastic die parts, but also for cold-working punching die, hot-working die-casting die and other parts.
Typical steels are high strength steels containing 18% nickel in the United States. Our country's brands are 00Ni18Co8Mo3TiAl, 0018Co8Mo5TiAl and 00Ni18Co12Mo4Ti2Al. They are equivalent to 18Ni (200), 18Ni (300) and 18Ni (350) in the United States, respectively. The brands of Hitachi Metal Company (YSS) in Japan are YAG250 YAG350 YAG285 and YAG350.
Because of the high content of alloying elements and the high price, the quality and life of the die have been significantly improved, and the economic benefits are good under some conditions. Particularly, parts with complex cavity, large interface difference, or changing unfavorable to quenching and hardening, or other die materials that are not competent, can be selected appropriately. The low alloy maraging steel developed in recent years in China is 06Ni6CrMoVTiAl.
Precipitation hardening steel.
This kind of age hardening steel contains fewer alloying elements than maraging steel, especially less precious metal Ni, so the price is relatively cheap. The typical representative is American P21 steel. The same type of steel military P21 in other countries should be developed as far as possible. Such as NAK55, NAK80 of Datong Special Steel Co., Ltd., and HPM1 of Hitachi Metal Co., Ltd. SM2CrNi3MoAl1s, 25CrNi3MoAl, SM1Ni3Mn2MoCuAl (code PMS), SM0Cr16Ni4Cu3Nb (code PCR) and SM2CrNi3AlMnMo (code SM2) have been developed in China, but they have not met the standard.
The hardness of this kind of steel in solution state is only about 30HRC, and its workability is good. After processing and aging treatment, the hardness can reach about 40HRC, and the deformation is very small. It is an economical precision plastic die steel.