Quenching and tempering usually refers to the quenching of steel and subsequent high temperature tempering, which is a common process in steel heat treatment. Its purpose is to improve the mechanical properties of the metal through appropriate heat treatment processes, so that it has good comprehensive mechanical properties. The following is a detailed introduction to the combination of quenching and high-temperature tempering:
1.Quenching
01Purpose
Improve hardness and strength: The austenite of steel is transformed into martensite through quenching, which significantly improves the hardness and strength of the material. Formation of martensite structure: The martensite structure has high hardness and strength, but is relatively brittle.
02Process
Heating: Heating the steel to the austenitizing temperature (usually between 750°C and 950°C) to completely transform its internal structure to austenite.
Rapid Cooling: Cooling the steel rapidly (usually in water, oil or air) to transform austenite into martensite.
03Result
Improved hardness: The hardness of the steel after quenching is greatly improved, and it can withstand greater mechanical stress.
Increased brittleness: Due to the presence of martensitic structure, the toughness of the steel after quenching is poor and brittle fracture is prone to occur.
2. High temperature tempering
01Purpose
Improve toughness and plasticity: High temperature tempering can reduce the brittleness after quenching and improve the toughness and plasticity of the material.
Eliminate internal stress: The internal stress generated during quenching will cause the material to become brittle, and high temperature tempering can effectively eliminate these internal stresses.
Adjust hardness: Adjust the hardness of the steel through tempering to achieve the expected performance requirements.
02Process
Heating: The quenched steel is heated to between 500°C and 650°C and kept at this temperature for a period of time.
Cooling: Usually cooling is done slowly to ensure the stability of the structure.
03Result
Hardness reduction: High-temperature tempering will moderately reduce the hardness of the material, but still maintain it at a high level.
Increased toughness: The toughness of tempered steel is significantly improved and can resist impact and fatigue damage.
Internal stress relief: The elimination of internal stress reduces the risk of material cracking and improves dimensional stability.
2. Comprehensive effect of quenching and high temperature tempering treatment
01Advantage
Good comprehensive mechanical properties: The steel after quenching and tempering has high hardness, high strength, good toughness and plasticity, and can meet various application requirements.
Dimensional stability: By eliminating internal stress, the dimensional stability of the material during use is ensured.
Wide application: It is suitable for manufacturing various mechanical parts, such as shafts, gears, springs, etc., and is widely used in machinery manufacturing, automobile industry, aerospace and other fields.
02Typical application
Mechanical parts: such as gears, bearings, connecting rods, etc., which require high strength and high toughness.
Structural parts: such as steel in bridges and building structures, which require durable and stable performance.
Tools: such as knives, molds, etc., which require high hardness and wear resistance.
03Conclusion
The combination of quenching and high temperature tempering optimizes the hardness, strength and toughness of steel through the quenching and tempering process, making it have excellent comprehensive mechanical properties. This treatment method is very important in industrial applications to ensure the reliability and durability of the material in actual use.
