Case Hardening & Tempering

This process is used to increase the hardness and tensile strength of the component or the case. The process is commonly performed within a special atmosphere, after which the item is rapidly cooled to improve fatigue life, wear resistance and, in some cases, corrosion properties. 

It should be noted that Hardening means to fully Through Harden a material, hardening and tempering is quite different from surface hardening or precipitation hardening. 

Hardening is carried out by heating the work to elevated temperatures (normally over 780
°C), followed by quenching, or cooling at a controlled rate. This rapid cooling transforms the steel structure and is done by quenching in oil or gas (for example). Because of the high temperatures involved, there will inevitably be some degree of distortion. 

After hardening, the material will often be in a fully stressed condition and, consequently, it must be tempered. This increases the toughness whilst optimising the required hardness. It is important that this process is done within a short time after Hardening otherwise cracking may occur due to the high stresses within the part.


For Technical or Sales enquiries:

Most processes are performed in highly sophisticated furnace equipment, specially designed to give the best results possible.
Hardening of metals and steels is a very broad subject and there are many different routes which can be used for different materials. If you are in any doubt about the best process for your purpose, we would advise that speak to one of our experienced metallurgists prior to specifying treatments. For details of the best person to speak to within your area refer to your nearest plant site for contact information.

Case Hardening is commonly carried out under controlled atmosphere sealed quench furnaces to medium carbon steels. Certain steels such as tool steels however benefit from hardening in vacuum. 

Vacuum Hardening - Freeze Hardening
Deep Freezing, sub zero or cryogenic treatment is sometimes necessary for certain steels after vacuum hardening, to provide further transformation of the steel structure. This process is done prior to final tempering.

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 Aalberts Surface Technologies Heat Ltd | Disclaimer

Registered Address.: Aalberts Surface Technologies Heat Ltd, Blackhorse Road, Letchworth. SG6 1HD 

Tel: 01462 472147