Water Quench & Temper
Quenching is the most important part of the heat treatment cycle and we have one of the largest water quenches in the UK containing 170,000 litres of water.
What are the applications and benefits?
Generally applied to the carbon steel range, this process hardens certain steels steel to the absolute maximum potential leading to the required combination of good mechanical properties, good impact values at low temperatures coupled with very stringent hardness specifications.
By developing the optimum combination of hardness, strength and toughness in an engineering steel, hardening and tempering offers component designers a route to savings in weight and material. Components can be machined or formed in a soft state and then hardened and tempered to a high level of mechanical properties.
How does the process work?
Steels are heated to their appropriate hardening temperature (usually between 800-900°C), held at temperature, then “quenched” (rapidly cooled) in water. This is followed by tempering (a soak at a lower temperature) which develops the final mechanical properties and relieves stresses. The actual conditions used for all three steps are determined by steel composition, component size and the properties required.
The treated material is transferred rapidly from furnace to quench in approximately 45 seconds. Immersion of the component in the quenchant happens quickly, at a rate of 2 feet per second. Highly agitated water, above and below the load, is consistent down the full length of the tank, initially breaking down the rapidly reforming vapour blanket and then enabling very high heat transfer rate into the water. Continuous oscillation of the cradle ensures that components are always in motion relative to the water preventing impingement of water jetting. In combination, these techniques enable us to surpass the performance of other heat treatment facilities.
The high volume of water available to transfer heat into results in a rise in water temperature of 2°c per tonne of steel quenched from 950°c. This water is constantly purified by bleeding off water resulting in two volume changes of the tank per week. Water temperature maintained between 10°c and 30°c through three independent cooling systems. Once the quench has been performed and the material is at ambient, it is in its fully hardened condition. This condition is generally when the material is at or near its highest tensile properties but will be brittle, therefore most hardening operations are performed with a tempering cycle to achieve the required mechanical properties the customer/specification desires.
Which materials can be treated?
Materials treated with a water quench and temper process include AISI 4130, AISI 8630, 50D, 20MnV6, F22, F65, F52, F60, SK15B, SK15C
How can Con Mech Engineers help?
The ultimate success of the thermal treatment cycle is wholly dependent on the quench process; rapidly and consistently cooling the steel to a depth within the component to meet test requirements. This is not a simple task and requires specific process and metallurgy expertise. At Con Mech Engineers we can tightly control all parameters of the water quenching process to reliably achieve the mechanical properties required. You can read more about the Water Quenching process in our Technical Resource Centre.