1. The main heat treatment methods of steel are as follows: Quenching. A heat treatment process in which steel is heated to a certain temperature above the critical point Ac3 or Ac1, and then cooled at a rate greater than the critical cooling rate to obtain martensite (or lower bainite) after heat preservation. Its purpose is to greatly increase the hardness of steel. annealing.

2. Quenching + high-temperature tempering (also called quenching and tempering treatment) heats the steel pipe to the quenching temperature to transform the internal structure of the steel pipe into austenite, and then rapidly cools it at a speed greater than the critical quenching speed to transform the internal structure of the steel pipe into martensite. Coupled with high-temperature tempering, the steel pipe structure is finally transformed into a uniform tempered troostite structure.

3. Normalizing steel: Normalizing is a heat treatment method that heats the steel above the critical temperature to transform all the steel into uniform austenite, and then cools it naturally in the air. Annealing of steel: A heat treatment process in which steel parts are heated to an appropriate temperature, kept warm for a period of time, and then cooled slowly, is called annealing.

4. Normalize the fire. Mainly used to improve mechanical properties, refine grains, and improve structure. Quenching. Steel is strengthened to obtain a martensitic structure. Tempering. Eliminate residual stress and obtain required performance.
5. The following introduces four common steel heat treatment methods. The first method is quenching. Quenching is to heat the steel above the critical temperature and then cool it rapidly to change its structure, thus improving its hardness and strength. Quenching methods include water quenching, oil quenching, gas quenching, etc.

6. Heat treatment of three common types of materials: steel, aluminum alloy, titanium alloy; the same material adopts different heat treatment processes to obtain different properties; common heat treatment processes of steel include: annealing, normalizing, quenching, tempering, and infiltration Carbon (carbonitriding), infiltrating metal or non-metal.