12Cr2Ni4A material gas carburizing and quenching method

Abstract

The invention discloses a 12Cr2Ni4A material gas carburizing and quenching method. The 12Cr2Ni4A material gas carburizing and quenching method successively comprises the following steps: atmosphere construction, feeding of workpieces into a furnace, pretreatment, conventional carburization, quenching, cryothermal treatment and low tempering, wherein during pretreatment, a part is insulated for a certain time at the temperature which is higher than a carburizing steel critical temperature (20-40 DEG C) and under the carbon potential of austenite saturated carbon concentration, thus, the surfaceof carburizing steel sufficiently absorbs carbon and carbide nucleuses, and the carburizing steel grows up to a certain size. The carbon potential in the furnace is monitored by an oxygen probe, thepretreatment is added before the conventional carburization, the process is simple, the repeatability is good, automatic production is easy to implement, controllability is good, and the efficiency ishigh; the used carbon potential is not high, the oxygen probe does not have carbon deposit easily, and the service life is long; and carbides formed by the pretreatment stops high-temperature austenite from growing up, a preheating effect is achieved, deformation of workpieces is relieved.

Description

Technical field [0001] The invention belongs to special processing technology and relates to a new process method for carburizing and quenching of 12Cr2Ni4A material. Background technique [0002] Currently, conventional carburizing methods (such as figure 1 The carburizing method shown) is difficult to obtain dispersed granular carbides in the 12Cr2Ni4A gear carburized layer. When the carburizing potential is increased, the carburized layer can obtain carbides, but the carbides are distributed along the grain boundaries and are in strips. , Claws and sharp corners, which are not conducive to the contact fatigue resistance of the gear; increasing the carbon potential to a higher value can obtain granular carbides, but too high carbon potential will easily make the furnace volume carbon, which is not conducive to the carbon potential measuring device ( Such as oxygen probe) accurately monitor the carbon potential in the furnace. The probe is at a high carbon potential for a long t...

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Problems solved by technology

[0002] At present, conventional carburizing methods (such as figure 1 The carburizing method shown) is difficult to obtain dispersed granular carbides in the 12Cr2Ni4A material gear carburized layer. When the carburizing carburization potential is increased, the carburized layer can obtain carbides, but the carbides are distributed along the grain boundaries in strips , claw-like and pointed-shaped, which is not conducive to the anti-cont

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