The cost of mold manufacturing is high, such as S136.8407.DC53.NAK80. Especially some sophisticated cold die, plastic die, die-casting die, etc. The use of heat treatment technology to improve the performance of the mold can greatly improve the life of the mold, and has significant economic benefits. China's mold technicians attach great importance to the development of mold heat treatment technology. There are several ways to heat treatment of the mold:
Vacuum heat treatment
The mold steel DC53 has a good surface state after vacuum heat treatment, and the deformation is small. Compared with the quenching under the atmosphere, the surface hardening of the mold after vacuum oil quenching is relatively uniform, and slightly higher. The main reason is that when vacuum heating, the surface of the mold steel is active, does not decarburize, and does not produce an oxide film that hinders cooling. When heated under vacuum, the surface of the steel has a degassing effect, and thus has high mechanical properties. The higher the degree of vacuum in the furnace, the higher the bending strength. After vacuum quenching, the fracture toughness of steel is improved, and the die life is generally increased by 40% to 400% or even higher than conventional processes. Cold working die vacuum quenching technology has been widely used.
2. Cryogenic treatment
Recent research work has shown that the mold steel can be improved by its cryogenic treatment (-196 ° C), and some molds have significantly improved the service life after cryogenic treatment. The deep cooling of the mold steel can be carried out between the quenching and tempering processes, or the cryogenic treatment after quenching and tempering. If retained austenite remains in the steel after quenching and tempering, a further tempering is required after the cryogenic treatment. Cryogenic treatment can improve the wear resistance and tempering stability of steel. Cryogenic treatment is not only used for cold work dies, but also for hot work dies and hard alloys. Cryogenic treatment technology has attracted more and more attention from mold heat treatment workers, and special cryogenic treatment equipment has been developed. The microstructure changes and microscopic mechanisms of different steel grades during deep cooling and their effects on mechanical properties need further study.
3. High temperature quenching and cooling quenching of the mold
Some hot work die steels, such as 3Cr2W8V, H13, 5CrNiMo, 5CrMnMo, etc., are heated and quenched higher than the conventional quenching temperature, which can reduce the amount of carbides in the steel, improve its morphology and distribution, and make the solid solution soluble in austenite. The distribution is uniformized, and more slab martensite can be obtained in the steel after quenching, thereby improving the fracture toughness and the thermal fatigue resistance, thereby prolonging the service life of the mold. For example, a hot extrusion die made of 3Cr2W8V steel has a conventional quenching temperature of 1080 to 1120 ° C and a tempering temperature of 560 to 580 ° C. When the quenching temperature is increased to 1200 ° C and the tempering temperature is 680 ° C (2 times), the mold life is increased several times.
W6Mo5Cr4V2, W18Cr4V high speed steel and Cr12MoV high alloy cold work die steel can reduce the quenching temperature appropriately to improve its plastic toughness and reduce the brittle cracking tendency, thus improving the die life. For example, the quenching temperature of W6Mo5Cr4V2 can be selected from 1140 to 1160 °C.
4. High energy beam heat treatment
The heat source for high energy beam heat treatment generally refers to a laser, an electron beam, an ion beam, and the like. Their common feature is that the surface power density of the supplied mold steel is at least 103 W/cm2. Their common features are: fast heating speed, heating area can be selected according to needs, the workpiece deformation is small, no cooling medium is needed, the processing environment is clean, the controllability is good, and the automatic processing is convenient. At home and abroad, more research has been done on the principle and process of high-energy beam heat treatment. The more mature ones are laser phase transformation hardening, small-sized electron beam processing and medium-power ion implantation, and have been applied in improving mold life.
Flashlight Rechargeable, Mini Flashlight for Camping,Mini Flashlight LED COB
Guangdong Dp Co., Ltd. , https://www.dp-light.com