Fri, 10 Aug 2018 03:22:17 +0000
What is quenching? Purpose and characteristics
Steel quenching is one of the steel is heated to a critical temperature Ac3 (hypoeutectoid steel) or Ac1 (hypereutectoid steel) above temperature, heat preservation for a period of time, make all or part of the austenitizing, then at greater than the critical cooling rate of cold faster cold below Ms to martensite isothermal near (or Ms) or bainite transformation of heat treatment process. Usually, the material such as aluminum alloy, copper alloy, titanium alloy, toughened glass is treated with solid solution or the heat treatment process with rapid cooling process is called quenching.
Purpose of quenching:
1) improve the mechanical properties of metal products or parts. For example: improve the hardness and wear resistance of tools and bearings, increase the elastic limit of springs, and improve the comprehensive mechanical properties of shaft parts.
2) improve the material properties or chemical properties of some special steels. For example, improve corrosion resistance of stainless steel, increase permanent magnetism of magnetic steel.
During quenching and cooling, there should be proper quenching medium, proper quenching method and common quenching methods, including single quenching, double quenching, stage quenching, isothermal quenching and local quenching.
After quenching, the steel workpiece has the following characteristics:
Imbalanced (that is, unstable) structures such as martensite, bainite, and residual austenite were obtained by ranel et al.
Larger internal stresses exist at phi.
The mechanical properties of the films cannot meet the requirements. Therefore, steel and iron workpiece after quenching generally through tempering