On 2018-08-08 14:48:54
Atmospheric carburizing and low pressure carburizing
Atmospheric carburizing heat treatment, low pressure carburizing heat treatment
Carburizing is the process of introducing carbon into the surface hardening of solid ferroalloy. It is completed by heating the metal in the carbon atmosphere above the transformation temperature for a predetermined time. After carburizing, the parts are quenched to harden the surface carburizing layer, and the core is not affected. It is a widely used case hardening process for low carbon steel, and the industrial importance of carburizing is expressed by its market share, because one third of all hardening heat treatment is covered by carburizing and hardening.
Advantages: carburizing and quenching produce a hard wear-resistant surface, and because of the soft core, the impact load is avoided, which is different from the surface hardening process, which is usually used for the depth of the case.
Low pressure carburizing (LPC) is a surface hardening process using hydrocarbon gas at very low pressure and high temperature in a vacuum furnace to obtain hardened tempered martensite surface layer and hard core. The treatment is used to increase the wear resistance and fatigue life of components.
Advantages: the root ratio (root depth) of carburized layer is almost 1:1 (uniform); compared with traditional carburized parts, it has high hardness below the surface; faster cycle time; parts can be carburized between 930 ° C and 1000 ° C (1700 ° and 1830 ° f); carbon penetration in deep blind hole leads to uniform hardness on the whole contour; carburized small hole and blind hole; due to high-pressure gas quenching (dry type) Quenching) to avoid the cleaning of parts after heat treatment; in the process of high-pressure gas quenching to reduce the size change through temperature independent heat transfer; enhanced mechanical properties - eliminate the oxide layer between particles, improve fatigue performance.