Overview of heat treatment tray:
Heat treatment tray tooling is widely used in industrial furnaces and kilns, and can be used in scientific research, military industry, metallurgy, petrochemical, coal, mining, electric power, machinery, building materials, papermaking, feed, environmental protection and other industries and departments. Because of its superior performance conditions, it has always been favored by consumers.
The heat treatment material tray tooling is mainly composed of 2-4 single-layer heat treatment material baskets. The material baskets are made by casting process and fixed into a whole with fixed rods, while ensuring sufficient stability.
The heat treatment tray is mostly used in continuous carburizing and nitriding furnace. Under the protective atmosphere in the furnace at 550-850℃, as the carrier of the workpiece, after the heat treatment process is completed and the next heat treatment process is completed, it needs to be resistant to rapid cooling and heating.
Heat treatment tooling is a kind of vulnerable parts, the main failure mode is high temperature oxidation and thinning, which seriously reduces the strength. Welding and casting methods are commonly used to make molds. Controlling tool materials and tool manufacturing costs is an important aspect of controlling heat treatment production costs.
The heat treatment material frame does not require thermal expansion and contraction. If stainless steel is used, it is easy to fail, the service life is short, and the cost is high. It is recommended to use ordinary A3 steel, which has good effect, long service life, small deformation and low cost.
Heat treatment refers to a metal thermal processing process in which the material is heated, insulated and cooled in a solid state to obtain the expected microstructure and performance.
Heat treatment process and heat treatment material frame selection materials:
1. Annealing operation method: After the steel parts are heated to Ac3+30~50℃ or Ac1+30~50℃ or below Ac1 (refer to relevant data), they are generally cooled slowly with the furnace temperature.
2. Normalizing operation method: heat the steel to 30~50 degrees above Ac3 or Accm, and then cool it at a cooling rate slightly higher than that of annealing.
3. Quenching operation method: heat the steel to the phase transition temperature Ac3 or Ac1 above, keep it for a period of time, and then quickly cool it in water, nitrate, oil or air. Purpose: Quenching is generally to obtain high hardness martensite structure, sometimes when quenching some high alloy steels (such as stainless steel, wear-resistant steel), it is to obtain a single uniform austenite structure to improve wear resistance and resistance Corrosive.
4. Tempering operation method: reheat the quenched steel to a certain temperature below Ac1, and then cool it in air, oil, hot water, and water after heat preservation.
5. Quenching and tempering operation method: high temperature tempering after quenching is called quenching and tempering, that is, the steel parts are heated to a temperature 10-20 degrees higher than that during quenching, quenched after heat preservation, and then tempered at a temperature of 400-720 degrees.
6. Aging operation method: heat the steel to 80~200℃, keep it for 5~20 hours or longer, then take it out with the furnace and cool it in the air. Purpose: 1. Stabilize the structure of steel parts after quenching, reduce deformation during storage or use; 2. Reduce internal stress after quenching and grinding, and stabilize shape and size.
7. Cold treatment operation method: Cool the quenched steel parts in a low temperature medium (such as dry ice, liquid nitrogen) to -60~-80℃ or lower, and the temperature is uniform, then take out the steel parts and warm to room temperature.
8. Flame heating surface quenching operation method: spray the flame of oxygen-acetylene mixture on the surface of the steel, heat it quickly, and spray water to cool it immediately after reaching the quenching temperature.
9. Induction heating surface quenching operation method: Put the steel sheet into the inductor, make the surface of the steel sheet generate an induction current, heat it to the quenching temperature in a very short time, and then spray water for cooling.
10. Carburizing operation method: Put the steel part into the carburizing medium, heat it to 900~950℃ and keep it warm, so that the steel part can obtain a certain concentration and depth of carburized layer.
11. Nitriding operation method: The active nitrogen atom decomposed by ammonia gas is at 5…~600℃, and the surface of the steel part is saturated with nitrogen to form a nitride layer.
12. Nitrocarburizing operation method: the steel surface is carburized and nitrided at the same time. Purpose: To improve the surface hardness, wear resistance, fatigue strength and corrosion resistance of steel parts.
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