What are the heat treatment temperatures for box type high-temperature resistance furnaces?

The heat treatment temperature range of the box type high-temperature resistance furnace is relatively wide, and it can usually be adjusted according to different material and process requirements. The following are some common temperature ranges and corresponding applications:

Low temperature range (100-650 ℃)
Stress relief annealing: For some metal materials that have undergone cold processing or welding, in order to eliminate internal residual stress and prevent deformation or cracking of the material during subsequent use, stress relief annealing treatment is usually carried out in this temperature range. For example, low carbon steel and low alloy steel welded components are generally subjected to stress relief annealing at 500-650 ℃.
Tempering: Tempering is a heat treatment process that is carried out immediately after quenching, with the aim of eliminating quenching stress, reducing material brittleness, and adjusting the balance between hardness and toughness. According to different tempering temperatures, it can be divided into low-temperature tempering (150-250 ℃), medium temperature tempering (350-500 ℃), and high-temperature tempering (500-650 ℃). For example, after quenching tool steel and mold steel, low-temperature tempering is often used to maintain high hardness and wear resistance; After quenching, the spring steel is tempered at a medium temperature to obtain good elasticity and toughness; After quenching, structural steel can undergo high-temperature tempering to obtain comprehensive mechanical properties with good strength and toughness.

Medium temperature range (650-1000 ℃)
Normalization: Normalization is a heat treatment process in which metal materials are heated to 30-50 ℃ above the critical temperature, held for an appropriate period of time, and then cooled in air. Mainly used to improve the cutting performance, refine grain size, enhance strength and toughness of low carbon steel and medium carbon steel. For example, for medium carbon steel with a carbon content of 0.25% -0.60%, the normalizing temperature is generally between 850-900 ℃.
Spheroidization annealing: Spheroidization annealing is mainly used for eutectoid steel and hypereutectoid steel, such as carbon tool steel, alloy tool steel, etc. The purpose is to spheroidize the carbides in the steel, reduce hardness, improve cutting performance, and prepare the structure for subsequent quenching. The spheroidization annealing temperature is generally between 720-780 ℃.
Incomplete quenching: For some medium carbon steel and medium carbon alloy steel, in order to achieve a better combination of strength and toughness, incomplete quenching process is sometimes used, which involves heating the steel between Ac1 and Ac3 (Ac1 is the lower critical temperature, Ac3 is the upper critical temperature), holding it for heat, and then quenching and cooling it. This process can retain a portion of undissolved ferrite, thereby improving the toughness of the steel. The incomplete quenching temperature is usually between 750-850 ℃.

High temperature range (1000-1300 ℃)
Complete quenching: For high carbon steel and high carbon alloy steel, such as bearing steel, high-speed steel, etc., in order to obtain high hardness and wear resistance, the complete quenching process is usually used, which heats the steel above the critical temperature to fully austenitize the structure of the steel, and then rapidly quenches and cools it. For example, the quenching temperature of high-speed steel is generally between 1220-1280 ℃.
Solution treatment: For some austenitic stainless steels and heat-resistant alloys, solution treatment is required to obtain a single-phase austenitic structure, improve corrosion resistance and high temperature strength. The alloy is heated to high temperature to fully dissolve various alloying elements in the austenite, and then rapidly cooled to obtain a supersaturated austenite structure. The solution treatment temperature for austenitic stainless steel is generally between 1050-1100 ℃.
High temperature diffusion annealing: For some ingots or castings, due to component segregation during solidification, high-temperature diffusion annealing is required to homogenize the components. This treatment is generally carried out at high temperatures of 1000-1300 ℃, with a long insulation time, which can last for several hours or even tens of hours. For example, for some aluminum alloy ingots, the diffusion annealing temperature may be between 500-550 ℃ (the melting point of aluminum alloys is relatively low), while for some high alloy steel ingots, the diffusion annealing temperature may be between 1200-1300 ℃.
Different materials and heat treatment processes have very strict temperature requirements. In practical applications, the optimal heat treatment temperature and process parameters need to be determined through experiments and experience based on specific material composition, workpiece size, performance requirements, and other factors.