Quenching and tempering refers to a heat treatment process used to improve the comprehensive mechanical properties of seamless steel pipes. That is, after quenching, it is subjected to high temperature tempering treatment. The purpose is to make the seamless steel pipe obtain a good combination of strength and toughness, which not only has high strength, but also has excellent toughness, plasticity, and cutting performance. Some alloy steel pipes or low-alloy steel pipes must be quenched and tempered to obtain good comprehensive properties. These steel pipes can also be called quenched and tempered steel pipes. After quenching and tempering treatment of ductile iron, it can not only improve the strength, but also improve the hardness and wear resistance.
Steps and principles of quenching and tempering of seamless steel pipes
Quenching is the first step, the heating temperature depends on the composition of the steel pipe, and the quenching medium is selected according to the hardenability of the steel and the size of the steel pipe. After quenching, the steel has large internal stress and is very brittle, and must be tempered in order to eliminate stress, increase toughness and adjust strength. Tempering is the most important process to finalize the mechanical properties of quenched and tempered steel pipes. The curve of the mechanical properties of various steel pipes changing with the tempering temperature, also known as the tempering curve of the steel pipe, can be used as the basis for selecting the tempering temperature. For the high temperature tempering of some alloy quenched and tempered steel pipes, attention should be paid to preventing the occurrence of the second type of temper brittleness to ensure the performance of the steel pipes.
Quenched and tempered steel
The so-called quenched and tempered steel generally refers to medium carbon steel with a carbon content of 0.3-0.6%. Generally, parts made of this type of steel are required to have good comprehensive mechanical properties, that is, good plasticity and toughness while maintaining high strength, so it is customary to call this type of steel quenched and tempered steel. It should be noted that sometimes quenched and tempered steel also refers to the process of adding manganese and silicon when smelting steel, so pay attention to the difference.
Heat treatment process of seamless steel pipe
The heat treatment process of seamless steel pipe includes methods such as annealing, normalizing, quenching, tempering and surface heat treatment. The tempering includes high temperature tempering, medium temperature tempering and low temperature tempering.
Reheating the quenched steel pipe to a certain temperature and then cooling it by a certain method is called tempering. Its purpose is to eliminate the internal stress generated by quenching, reduce hardness and brittleness, and achieve the expected mechanical properties.
Note: Quenching and tempering usually refers to the heat treatment process of quenching + high temperature tempering to obtain tempered sorbite.
Steps and principles of quenching and tempering of seamless steel pipes
Quenching is the first step, the heating temperature depends on the composition of the steel pipe, and the quenching medium is selected according to the hardenability of the steel and the size of the steel pipe. After quenching, the steel has large internal stress and is very brittle, and must be tempered in order to eliminate stress, increase toughness and adjust strength. Tempering is the most important process to finalize the mechanical properties of quenched and tempered steel pipes. The curve of the mechanical properties of various steel pipes changing with the tempering temperature, also known as the tempering curve of the steel pipe, can be used as the basis for selecting the tempering temperature. For the high temperature tempering of some alloy quenched and tempered steel pipes, attention should be paid to preventing the occurrence of the second type of temper brittleness to ensure the performance of the steel pipes.
Quenched and tempered steel
The so-called quenched and tempered steel generally refers to medium carbon steel with a carbon content of 0.3-0.6%. Generally, parts made of this type of steel are required to have good comprehensive mechanical properties, that is, good plasticity and toughness while maintaining high strength, so it is customary to call this type of steel quenched and tempered steel. It should be noted that sometimes quenched and tempered steel also refers to the process of adding manganese and silicon when smelting steel, so pay attention to the difference.
Heat treatment process of seamless steel pipe
The heat treatment process of seamless steel pipe includes methods such as annealing, normalizing, quenching, tempering and surface heat treatment. The tempering includes high temperature tempering, medium temperature tempering and low temperature tempering.
Reheating the quenched steel pipe to a certain temperature and then cooling it by a certain method is called tempering. Its purpose is to eliminate the internal stress generated by quenching, reduce hardness and brittleness, and achieve the expected mechanical properties.
Note: Quenching and tempering usually refers to the heat treatment process of quenching + high temperature tempering to obtain tempered sorbite.
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