In order to avoid cooling warping after machining, in general, tungsten carbide needs to be heat treated, after tempering, the strength of the tool will be reduced after tempering, and the plasticity and toughness of cemented carbide will increase. Therefore, for cemented carbide, heat treatment is a more important process. Today, the editor of Chuangrui will talk to you about the relevant knowledge of vacuum heat treatment.
In the processing and production of vacuum heat treatment, there are often problems with "coloring" on the surface of processed products. Achieving a bright-looking, uncolored product processing effect is the common goal pursued by the R&D and users of vacuum furnaces. So what is the reason for the brightness? What factors are involved? How can I make my product shiny? This is a matter of great concern to the front-line technicians in production.
The coloration is caused by oxidation, and the different colors are related to the temperature generated and the thickness of the oxide film. Quenching in oil at 1200°C will also cause carburizing and melting of the surface layer, and too high a vacuum will cause element volatilization and bonding. These can damage the brightness of the surface.
In order to obtain a better bright surface, the following measures should be paid attention to and considered in production practice:
1. First of all, the technical indicators of the vacuum furnace should meet the national standards.
2. The process treatment should be reasonable and correct.
3. The vacuum furnace should not be polluted.
4. If necessary, wash the furnace with high-purity inert gas before entering and leaving the furnace.
5. It should go through a reasonable oven in advance.
6.Reasonable selection of inert gas (or a certain proportion of strong reducing gas) during cooling.
It is easier to obtain a shiny surface in a vacuum furnace because it is not easy and expensive to obtain a protective atmosphere with a dew point of -74°C. However, it is easy to obtain a vacuum atmosphere with a dew point equivalent to -74°C and the same impurity content. In the processing and production of vacuum heat treatment, stainless steel, titanium alloy, and high-temperature alloy are relatively difficult. In order to prevent the volatilization of elements, the pressure (vacuum) of tool steel should be controlled at 70-130Pa.
Post time: Nov-05-2024