CN105002330A - Gear steel heat treatment process - Google Patents

Abstract

The invention relates to a gear steel heat treatment process. The gear steel heat treatment process includes the step of surface quenching, the step of carburizing involving three-time carburizing and three-time diffusing, the step of hardening and tempering and the step of normalizing treatment. Through the gear steel heat treatment process, the content of retained austenite on the surface of a gear and the thickness of a non-martensite layer on the surface of the gear are reduced. By the adoption of the high-temperature carbon potential changing method, production efficiency is improved. Thus, the tissue performance of the tissue surface is greatly improved, and the phenomenon of tooth breakage cannot occur.

Description

A kind of Pinion Steel thermal treatment process

Technical field

the present invention relates to casting technology field, particularly relate to a kind of Pinion Steel thermal treatment process.

Background technology

In prior art, in Pinion Steel heat treatment process, gear can increase the intensity of hardened layer through carbonitriding, but due to misoperation, surface layer excessive concentration may be caused, be that the carbide of separating out is separated out with horn shape or netted form, tissue surface structure property can be caused seriously to reduce, easy generation tooth collapses, and easy stress concentration.Traditional carburization process oozes by force in 920 ~ 930 DEG C, carbon potential 1.2%CP, is incubated 7 ~ 9 hours, then carry out diffusion temperature 920 ~ 930 DEG C, carbon potential 0.8%CP, be incubated 5 ~ 7 hours, be cooled to quenching temperature afterwards to quench, the process time is long, and efficiency is low.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of Pinion Steel thermal treatment process, and gear surface residual austenite content and non-martensite layer thickness are reduced, and adopts high temperature change carbon potential method to enhance productivity.

For solving the problems of the technologies described above, the present invention relates to a kind of Pinion Steel thermal treatment process, comprising:

A, carry out hard surfacing;

B, carburizing and quenching: comprise three carburizings and triple diffusion; Precooling, is chilled to 730-740 DEG C in advance by gear, insulation 2-3 hour; Primary quenching, by gear dip quench oil, temperature remains on 115-120 DEG C, and stirs quenching oil; Cleaning, cleans gear with gasoline; High tempering, is heated to 725-730 DEG C by gear, and is incubated 2-3 hour, and high tempering carries out within an hour after primary quenching; Preheating, is preheated to 735-740 DEG C by gear, insulation 2-3 hour; Secondary quenching, by gear dip quench oil, temperature remains on 125-130 DEG C, and stirs quenching oil; Cleaning, cleans gear with gasoline; Low-temperaturetempering, is heated to 165-170 DEG C by gear, and is incubated 2-3 hour, and high tempering carries out within an hour after secondary quenching;

C, carry out modified;

D, normalizing treatment.

In preferred version, described three carburizings and triple diffusion comprise:

First time oozes by force, and furnace temperature maintains 960-968 DEG C, is incubated as 160-180min, in meshbeltfurnace, carbon potential is in 1.54-1.57%CP, first time diffusion, and furnace temperature maintains 950-958 DEG C, insulation 110-135min, in meshbeltfurnace, carbon potential is 1.20-1.23%CP; Second time is oozed by force, and furnace temperature maintains 950-958 DEG C, insulation 80-85min, and in meshbeltfurnace, carbon potential is 1.28-1.35%CP, second time diffusion, and furnace temperature maintains 940-948 DEG C, insulation 80-95min, and in meshbeltfurnace, carbon potential is 0.95-1.2%CP; Third time oozes by force, and furnace temperature maintains 938-943 DEG C, insulation 45-50min, and in meshbeltfurnace, carbon potential is 1.17-1.33% CP, third time diffusion, and furnace temperature maintains 925-940 DEG C, and insulation 45-60min, in meshbeltfurnace, carbon potential is 0.95-0.98%CP.

Beneficial effect of the present invention is: by providing a kind of Pinion Steel thermal treatment process, and gear surface residual austenite content and non-martensite layer thickness are reduced; Adopt high temperature to become carbon potential method to enhance productivity; Tissue surface structure property is improved greatly, tooth can not be produced and collapse phenomenon.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with embodiment, the present invention is further elaborated.

The present invention relates to a kind of Pinion Steel thermal treatment process, comprise the steps:

A, carry out hard surfacing;

B, carburizing and quenching: comprise three carburizings and triple diffusion; Precooling, is chilled to 730-740 DEG C in advance by gear, insulation 2-3 hour; Primary quenching, by gear dip quench oil, temperature remains on 115-120 DEG C, and stirs quenching oil; Cleaning, cleans gear with gasoline; High tempering, is heated to 725-730 DEG C by gear, and is incubated 2-3 hour, and high tempering carries out within an hour after primary quenching; Preheating, is preheated to 735-740 DEG C by gear, insulation 2-3 hour; Secondary quenching, by gear dip quench oil, temperature remains on 125-130 DEG C, and stirs quenching oil; Cleaning, cleans gear with gasoline; Low-temperaturetempering, is heated to 165-170 DEG C by gear, and is incubated 2-3 hour, and high tempering carries out within an hour after secondary quenching;

C, carry out modified;

D, normalizing treatment.

Wherein three carburizings and triple diffusion comprise:

First time oozes by force, and furnace temperature maintains 960-968 DEG C, is incubated as 160-180min, in meshbeltfurnace, carbon potential is in 1.54-1.57%CP, first time diffusion, and furnace temperature maintains 950-958 DEG C, insulation 110-135min, in meshbeltfurnace, carbon potential is 1.20-1.23%CP; Second time is oozed by force, and furnace temperature maintains 950-958 DEG C, insulation 80-85min, and in meshbeltfurnace, carbon potential is 1.28-1.35%CP, second time diffusion, and furnace temperature maintains 940-948 DEG C, insulation 80-95min, and in meshbeltfurnace, carbon potential is 0.95-1.2%CP; Third time oozes by force, and furnace temperature maintains 938-943 DEG C, insulation 45-50min, and in meshbeltfurnace, carbon potential is 1.17-1.33% CP, third time diffusion, and furnace temperature maintains 925-940 DEG C, and insulation 45-60min, in meshbeltfurnace, carbon potential is 0.95-0.98%CP.

Be more than better embodiment of the present invention, but protection scope of the present invention is not limited thereto.Any those of ordinary skill in the art are in the technical scope disclosed by the present invention, and the conversion expected without creative work or replacement, all should be encompassed within protection scope of the present invention.Therefore the protection domain that protection scope of the present invention should limit with claim is as the criterion.

Claims (2)

1. a Pinion Steel thermal treatment process, is characterized in that, comprises the steps

A, carry out hard surfacing;

B, carburizing and quenching: comprise three carburizings and triple diffusion; Precooling, is chilled to 730-740 DEG C in advance by gear, insulation 2-3 hour; Primary quenching, by gear dip quench oil, temperature remains on 115-120 DEG C, and stirs quenching oil; Cleaning, cleans gear with gasoline; High tempering, is heated to 725-730 DEG C by gear, and is incubated 2-3 hour, and high tempering carries out within an hour after primary quenching; Preheating, is preheated to 735-740 DEG C by gear, insulation 2-3 hour; Secondary quenching, by gear dip quench oil, temperature remains on 125-130 DEG C, and stirs quenching oil; Cleaning, cleans gear with gasoline; Low-temperaturetempering, is heated to 165-170 DEG C by gear, and is incubated 2-3 hour, and high tempering carries out within an hour after secondary quenching;

C, carry out modified;

D, normalizing treatment.

2. Pinion Steel thermal treatment process as claimed in claim 1, it is characterized in that, described three carburizings and triple diffusion comprise:

First time oozes by force, and furnace temperature maintains 960-968 DEG C, is incubated as 160-180min, in meshbeltfurnace, carbon potential is in 1.54-1.57%CP, first time diffusion, and furnace temperature maintains 950-958 DEG C, insulation 110-135min, in meshbeltfurnace, carbon potential is 1.20-1.23%CP; Second time is oozed by force, and furnace temperature maintains 950-958 DEG C, insulation 80-85min, and in meshbeltfurnace, carbon potential is 1.28-1.35%CP, second time diffusion, and furnace temperature maintains 940-948 DEG C, insulation 80-95min, and in meshbeltfurnace, carbon potential is 0.95-1.2%CP; Third time oozes by force, and furnace temperature maintains 938-943 DEG C, insulation 45-50min, and in meshbeltfurnace, carbon potential is 1.17-1.33% CP, third time diffusion, and furnace temperature maintains 925-940 DEG C, and insulation 45-60min, in meshbeltfurnace, carbon potential is 0.95-0.98%CP.