What is the difference between annealing and tempering ?

Annealing: It is to heat the workpiece to an appropriate temperature, adopt different holding times according to the material and the size of the workpiece, and then carry out slow cooling, with the purpose of making the internal structure of the metal reach or close to the equilibrium state, obtain good process performance and use performance, or prepare for further quenching.

Tempering: It is a heat treatment process in which the steel parts are hardened, then heated to a certain temperature below the AC1 point, kept warm for a certain time, and then cooled to room temperature. Workpieces with different uses should be tempered at different temperatures to meet the requirements in use.

The main function of annealing is to soften the metal and strengthen the toughness, which is applied to a variety of metal processing; Tempering is mainly used to reduce brittleness after quenching of steel parts.

1. Annealing of steel.

Annealing is a commonly used preparatory heat treatment process in production. After annealing, the blanks of most machine parts and tools and molds can eliminate the internal stress and structural inhomogeneity of casting, forging and welding parts; It can improve and adjust the mechanical properties of steel, and prepare for the next process. For parts that do not require high performance and are not very important, as well as some ordinary castings and weldments, annealing can be used as the final heat treatment.

The annealing of steel is a heat treatment process in which the steel is heated to the appropriate temperature, kept warm for a certain period of time, and then slowly cooled to obtain a near-equilibrium structure. The purpose of annealing is to homogenize the chemical composition, improve mechanical and process properties, eliminate or reduce internal stresses, and prepare the part for final heat treatment.

There are many types of annealing processes for steel, which can be divided into two categories according to the heating temperature: one is annealing above the critical temperature (AC3 or AC1), also known as phase change recrystallization annealing. Including complete annealing, incomplete annealing, isothermal annealing, spheroidization annealing and diffusion annealing, etc.; The other type is annealing below the critical temperature (AC1), also known as low-temperature annealing.

These include recrystallization annealing, stress relief and dehydrogenated annealing. According to the cooling method, it can be divided into continuous cooling annealing and isothermal annealing.

2. Tempering of steel.

Tempering is a heat treatment process in which quenched steel is heated to a certain temperature below the A1 point for a certain period of time, and then cooled to room temperature in an appropriate way. It is the next heat treatment process immediately after quenching, which determines the structure and properties of the steel in the use state, and is related to the service life of the workpiece, so it is a key process.

The main purpose of tempering is to reduce or eliminate quenching stress; Ensure the corresponding organizational transformation, so that the size and performance of the workpiece are stable; Improve the thermal and plastic properties of steel, choose different tempering temperatures, and obtain the appropriate combination of hardness, strength, plasticity or toughness to meet the performance requirements of different workpieces.

What does normalizing, annealing, quenching, and tempering mean? Have you figured it all out?

Annealing is a metal heat treatment process in which metal is slowly heated to a certain temperature, held for a sufficient amount of time, and then cooled at a suitable rate. The purpose is to reduce hardness and improve machinability; Eliminate residual stress, stabilize the dimension, reduce deformation and crack tendency; Refine the grains, adjust the tissue, and eliminate tissue defects.

Tempering is the process of heating quenched steel below the austenite transition temperature, holding it for 1 to 2 hours and then cooling. Tempering is often accompanied by quenching and is the final step in heat treatment. After tempering, the structure of the steel tends to be stable, the brittleness of the quenched steel is reduced, the toughness and plasticity are improved, the quenching stress is eliminated or reduced, the shape and size of the steel are stabilized, the deformation and cracking of the quenched parts are prevented, and the high-temperature tempering can also improve the cutting performance.

1.Complete annealing and isothermal annealingComplete annealing is also weighed crystallization annealing, generally referred to as annealing, this annealing is mainly used for casting, forgings and hot-rolled profiles of various carbon steels and alloy steels of sub-eutectic composition, and sometimes also used for welded structures. Generally, it is often used as the final heat treatment of some unimportant workpieces, or as the pre-heat treatment of some Chanzhou workpieces.

2.Spheroidized annealing is mainly used for pereutectic carbon steel silver acres and alloy tool steels (such as steel grades used in the manufacture of cutting tools, measuring tools, and molds). The main purpose is to reduce hardness, improve machinability and prepare for later quenching.

3.Stress Relief Annealing Stress Annealing is also known as low temperature annealing (or high temperature tempering), this annealing is mainly used to eliminate the residual stress of castings, forgings, welded parts, hot rolled parts, cold drawn parts, etc.

Hello! Its differences are as follows:

Annealing is a heat treatment process in which the metal or alloy is heated to an appropriate temperature, kept warm for a certain period of time, and then slowly cooled with the furnace.

Quenching is a heat treatment process in which steel is heated to a certain temperature above the AC3 or AC1 point, held for a certain period of time, and then cooled at an appropriate rate to obtain martensite and/or bainite structure.

Tempering is a heat treatment process in which the steel is hardened, then heated or excavated to a certain temperature below the AC1 point, kept warm for a certain time, and then cooled to room temperature.

Normalizing is to heat the workpiece to a suitable temperature and then cool it in the air, the effect of normalizing is similar to annealing, but the resulting structure is finer, often used to improve the cutting performance of the material, and sometimes used for some parts with low requirements as the final heat treatment.