Mold steal vacuum heat treatment technology

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The service condition of the mold is very important. It needs to bear large tensile, compressive and shear loads, often in a complex state of stress, and is also subjected to periodic impact loads, often at high temperatures, accompanied by strong Work in harsh conditions of mechanical wear, so the mold must have quite high mechanical strength, high temperature hardness, sufficient toughness, good wear resistance and anti-seizure ability to ensure a fairly high durability of the mold; this requires a reasonable selection of materials And it is realized by the proper heat treatment process and superb heat treatment operation technology. Through heat treatment, the necessary strength, toughness and wear resistance are given to the mold, which greatly improves the life of the mold. With the rapid development of science and technology, heat treatment technology has also developed rapidly. People have innovated the traditional heat treatment process, and constantly adopted new processes to improve the level of heat treatment technology. Among them, vacuum heat treatment technology is the most prominent, which effectively solves the three major problems in the heat treatment process: deformation, cracking, and hardening, and greatly improves the quality of the mold. service life.

With the increasingly high requirements for mold quality, it is difficult for general heat treatment methods to meet the requirements. Vacuum heat treatment of mold parts has become an important way to improve product quality for high-precision molds. After vacuum heat treatment of die steel, the surface is not oxidized or decarburized, the quenching deformation is small, the surface hardness is uniform, the fracture toughness of the steel is improved, and the service life of the mold is generally improved, which can generally be increased by 40%~400%. or even higher. Mold vacuum heat treatment technology has been widely used in my country.

In the past ten years, new technologies and processes of vacuum heat treatment have been widely developed and applied in various parts of my country. The currently used vacuum heat treatment equipment includes: vacuum annealing furnace, vacuum oil quenching furnace, vacuum high-pressure air-cooled furnace, vacuum high-pressure air-cooled classification or isothermal quenching furnace , Vacuum tempering furnace, vacuum carburizing furnace, vacuum nitriding furnace, vacuum metal infiltrating furnace, etc.

Vacuum quenching

Vacuum quenching technology has been widely used in various carburized structural steel, alloy steel, high-speed steel, stainless steel and various aging alloys. After the mold is vacuum quenched, the surface brightness is good, the deformation is small, the hardness is high and uniform, and the service life is long. The vacuum quenching process parameters of some commonly used materials are shown in the figure.

Vacuum nitriding technology

In the process of vacuum nitriding, since other gases and adherents adsorbed on the surface of the mold will be “pumped” and discharged out of the furnace, the activity of the steel surface is greatly improved, which promotes the elimination of reactive nitrogen sources during the nitriding process. The absorption of Yu accelerates the process of nitriding. In addition, the non-nitriding atmosphere in the furnace, especially the oxidizing atmosphere, should be passed into NH before heating for ordinary gas nitriding, but there will still be a small amount of oxidizing atmosphere in the furnace, even high-purity gas, which also contains 0.1% of impurities. In the vacuum of 1.33Pa, the impurity content is only 0.001%. It can be seen that the purification effect of vacuum nitriding has two aspects, one is to purify the surface of the workpiece, and the other is to purify the atmosphere in the furnace.

In addition, compared with ion nitriding, vacuum nitriding has the following characteristics: First, the nitriding temperature is uniform and easy to control, while the workpiece is heated by the bombardment of positive ions during ion nitriding, and there are certain difficulties in temperature measurement and control; Second, the quality of the nitriding surface is high. During the ion nitriding process, positive ions continuously bombard the surface of the workpiece, resulting in many small pits on the surface, especially when the current is large. It is difficult for workpieces with complex shapes and small holes to obtain a uniform nitriding layer during ion nitriding. Vacuum nitriding is due to gap-type air extraction. The atmosphere in the furnace flows more uniformly than ordinary gas nitriding, which ensures the workpiece. All parts can get a uniform nitrided layer.

Recommended vacuum heat treatment equipment: The vacuum heat treatment furnace produced by SIMUWU is a high-quality product for the vacuum heat treatment process of tooling and molds. Good temperature control accuracy and temperature control uniformity ensure the effective progress of the vacuum heat treatment process. SIMUWU specializes in the manufacture of vacuum furnaces, has more than ten years of relevant experience, and has a good reputation in the field of vacuum furnace manufacturing. The product line includes vacuum air quenching furnace, vacuum oil quenching furnace, vacuum brazing furnace, etc., which are widely sold in developed and developing countries.