Medium carbon alloy steel chain pin shaft heat treatment method

Abstract

The invention discloses a medium carbon alloy steel chain pin shaft heat treatment method. A carbonitriding quenching and tempering treatment process with the front area and rear area of a meshbeltfurnace adjusting the temperature and carbon potential is adopted, a chain pin shaft with cold extrusion in place is enclosed into the meshbeltfurnace with controllable atmosphere, in the atmosphere protection environment, the front area heating temperature is set as 850 + / - 10 DEG C, the carbon potential (Cp) is set as (1.1 + / - 0.1)%, the rear area heating temperature is reduced to 830 + / - 10 DEG C,the carbon potential (Cp) is reduced to (0.9 + / - 0.1)%, the total heat preservation time of the front area and rear area is 110-130 minutes, then the chain pin shaft is subjected to tempering treatment after being quenched by quenching oil, the tempering temperature is 150-190 DEG C, and the tempering heat preservation time is 120-150 minutes. According to the medium carbon alloy steel chain pinshaft heat treatment method, by means of the manners that the different temperature of the front area and rear area of the meshbeltfurnace with the controllable atmosphere is adjusted, and long time heat preservation is performed, more nitrogen atoms are made to be infiltrated into the surface of the chain pin shaft, the infiltrating layer tissue with the pin shaft surface infiltrating layer hardness being high and the hardness gradient being low and gentle is obtained, and the wear resistance of the pin shaft is improved.

Description

technical field [0001] The invention relates to the technical field of thermal processing of chain pins, in particular to a heat treatment method for medium carbon alloy steel chain pins. Background technique [0002] At present, medium carbon alloy steel chain pins are often processed by periodic furnace or continuous mesh belt furnace, and processed by medium temperature carbonitriding direct quenching and tempering heat treatment process. Heating temperature: 860℃±10℃, carbon potential Cp: 1.1±0.1%, oil temperature: 60±20°C, holding time is 90-110 minutes, tempering temperature is 170°C-210°C, tempering holding time is 120-150 minutes; needle-like martensite is obtained on the pin surface Structure, the core is low-carbon martensite, this structure can keep the pin shaft with good wear resistance and a certain degree of toughness. The disadvantage is that the nitrogen content in the permeation layer on the surface of the pin shaft is low, the surface hardness is not high...

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Problems solved by technology

[0003] Aiming at the deficiencies of the prior art, the present invention provides a heat treatment method for the pin shaft of a medium-carbon alloy steel chain, which solves the problems of insufficient surface hardness and poor stability of the pin shaft in the prior art, and improves the wear resistance of the chain pin shaft , prolong the service life of the chain

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