Gas Heat Treatment
Gas heat treatment is a heat treating process under various gas atmosphere and temperature mainly to improve hardness, wear resistance and fatigue or tensile strength properties of various mechanical steel parts.
Thai Parkerizing can support various types of Gas heat treatment services as follow,
- Gas Carburizing and Tempering
- Gas Carbonitriding and Tempering
- Quenching and Tempering
*Special process: Botan (Carbon protection process)
Gas carburizing is a method to increase surface hardness of mild or low alloy steel by heating the steel to 850oC - 940oC.
This is a process in which carbon is infiltrated into the surface and carburized, then hardened by rapid cooling (Quenching) at a lower temperature. This method can usually achieve both opposing "toughness and hardness".
Sometimes it is necessary to prevent carburizing on certain areas of a part. Preventing carburization in selective areas can be done with mechanical masking or chemical coating (Botan process)
Carbonitriding is a process in which carbon and nitrogen are simultaneously infiltrated into the surface of steel at a temperature of about 800oC to 880oC, lower than ordinary gas carburizing.
The hardenability is improved by nitriding, it is possible to treat non-alloy steel such as SPCC and low carbon steel which cannot be applied by gas carburizing, and the reduction of material cost is also a great advantage.
Since it can be quenched at a lower temperature than gas carburizing, deformation and distortion due to heat treatment can be reduced.
Quenching and Tempering
Quenching and Tempering is a heat treatment process which changes the state of martensite structure by heating steel with carbon content of 0.3% or more to the austenitizing temperature around 850oC and then rapidly cooled in water or oil.
After that, tempering is usually performed for the purpose of providing toughness to the steel hardened by quenching.