What is Through Hardening / Quench & Temper?
Through hardening, also known as “quench & temper”, is a process that consists of heating the parts to a temperature above the transformation range and then rapidly cooling to room temperature, usually using an oil quench. This may be performed in air or in a controlled atmosphere to protect the part’s surface. Parts are then reheated to a lower temperature to temper to the desired final hardness range.
Through hardening occurs via heat treatment of medium and high carbon steels (>0.25% carbon). First, ovens heat the steel above its critical temperature, which lies between 1500°F – 1900°F depending on alloy. Second, the material is cooled rapidly by dunking the material in water or oil in a process known as quenching. Finally, following quenching, tempering, or annealing by reheating eliminates excess brittleness in the material. This process results in increased hardness throughout the material. Consequently, the increased hardness also leads to increased brittleness. In fact, the relatively brittle metal can fracture under impact or shock loads.
The outcome of any heat treating method is essentially based on three variables: the temperature to which the metal is heated, the amount of time it is held at that temperature, and the method and rate of cooling. These variables are adjusted according to the type of material being treated and the desired effect of the treatment. Cooling can be achieved with gas, in salt, in air, or in oil.
JAAS is a metalworking company specializing in heat treating. We can achieve heating temperatures of up to 2400° F . The work we do supports various industries, from automobile, aerospace, Wind farms to computers and heavy equipment.
Benefits
- Improves strength and hardness
- Controllable specific mechanical properties
- Same hardness throughout part
- Increases lifespan of part
Typical Materials Used for Through Hardening / Quench & Temper
- Medium to High Carbon Steels
- Medium Carbon Alloy Steels
- Cast Iron
