1，And the characteristics of direct quenching and low temperature tempering 1, organization: grain can not be refined steel. The quenching deformation of large, alloy steel carburizing surface residual austenite content more, the lower surface hardness
Scope of application: simple operation, low cost for treatment on the deformation and impact load to the small parts, suitable for gas carburizing and liquid carburizing process.
2, pre cooling direct quenching, tempering, quenching temperature and performance characteristics of 800-850 ℃ organization: can reduce the workpiece deformation hardening, carburizing layer residual austenite can also be slightly lower, the surface hardness increased slightly, but the austenite grain size does not change.
Scope of application: the operation is simple, the oxidation, decarburization and quenching deformation is small, is widely applied to all kinds of tools for fine grain steel.
3, a heating and quenching, tempering, quenching temperature of 820-850 ℃ and 780-810 ℃ organization and properties of the heart: high strength requirements, the quenched at 820-850 ℃, the heart for low carbon M, surface requires high hardness, the quenched at 780-810 ℃ can refine grain.
Scope of application: applicable to coarse grain steel after solid carburizing carbon steel and low alloy steel workpiece, gas, liquid carburizing, carburizing carburizing workpiece and some are not suitable for direct quenching after machining parts.
4 high temperature tempering, carburizing, quenching and low temperature tempering a,, and performance characteristics of quenching temperature of 840-860 ℃ tempering organization: the M and residual A decomposition, infiltration of carbon and alloy elements in the form of carbide precipitation in the layer, then for cutting and reduce the residual A after quenching.
Application: mainly used in Cr - Ni alloy carburizing workpiece
5, two times tempering quenching temperature and performance characteristics: the first quenching (or normalized), can eliminate the carburized layer network carbide and refining the core structure (850-870 ℃), second times quenching mainly improve diffusion layer structure, the requirement of performance is not heart of quenching between material Ac1 - Ac3, of heart performance requirements, to quench above Ac3.
Application: mainly used for important carburizing of high mechanical properties, especially for coarse grain steel. But in the carburizing after two times of high temperature heating, the workpiece deformation and oxidation and decarbonization increased, heat treatment process is complicated.
6, two times the quenching process and performance characteristics: high temperature tempered structure on Ac1 or Ac3 (Center) of the quenching temperature, high alloy surface residual A more, after cold treatment (-70 ℃ /-80 ℃) prompted the A transformation in order to improve the surface hardness and wear resistance.
Application: mainly used in high alloy steel for carburizing without machining a workpiece.
Induction heating quenching and low temperature tempering, carburizing microstructure and performance characteristics of 7: can refine the infiltration layer and near the layer division organization. The quenching deformation is small, do not allow the hardened parts without pre cutoff.
Applicable scope: all kinds of gear and shaft

Su's heat treatment Co. Ltd. was founded in 1990, after decades of development, scale is continually expanding, is located in Shajing Town Baoan District Shenzhen City Bridge second industrial zone, covering an area of 3000 square meters, the main business is to take all the metal, alloy steel, beryllium copper, heat treatment of high speed steel, cryogenic treatment (-196 C), nitrogen gas, liquid nitrogen, QPQ salt bath production line, high-frequency quenching, blackening and carburizing, the surface of hard and stainless steel processing.
The company is equipped with power of heat treatment technology, established a perfect quality testing equipment, equipped with vacuum quenching furnace, vacuum furnace, pit furnace, furnace, liquid nitrogen atmosphere furnace, rotary furnace, large mesh belt furnace, improve metallographic inspection equipment, material failure analysis, scientific management and complete, rigorous technology, skilled operation.
Company will be excellent quality and perfect service, and actively challenge, satisfy customer demand, has passed ISO9001:2000 in 2003 September (SGS) international quality certification. Has now become a reputable manufacturers.