22CrSH+齿套钢热处理工艺及组织性能

（工程硕士）

22CrSH齿套钢热处理工艺及组织性能 HEAT TREATMENT, MICROSTRUCTURE AND PROPERTIES OF

22CRSH GEARBOX STEEL

刘宏光

哈尔滨工业大学

2007年4月

图书分类号：TG142.25

U.D.C.:669

工程硕士学位论文

22CrSH齿套钢热处理工艺及组织性能

硕士研究生：刘宏光

导

副导师：甄 良 教授 师：徐香秋 高级工程师

申请学位级别：工程硕士

学科、专业：材料学

所在单位：长春一汽集团

答辩日期：2007年4月

授予学位单位：哈尔滨工业大学

Classified Index：TG142.25

U.D.C.: 669

A Dissertation for the Degree of Master of Engineering

HEAT TREATMENT, MICROSTRUCTURE

AND PROPERTIES OF 22CRSH

GEARBOX STEEL

Candidate:

Supervisor:

Associate Supervisor:

Academic Degree Applied for:

Speciality:

Affiliation:

Date of Oral Examination:

University: Liu Hongguang Prof. Zhen Liang Senior Engineer. Xu Xiangqiu Master of Engineering Materials Science Changchun First Automobile Group April, 2007 Harbin Institute of Technology

哈尔滨工业大学工程硕士学位论文

摘 要

本文针对红旗轿车016传动器同步器齿套生产中存在的问题，研究了新型齿套材料22CrSH钢奥氏体化温度、变形、冷却速度对相转变、相组织的影响，以及22CrSH钢的切削性能和热处理工艺，获得了以下研究结果：

在奥氏体状态下，22CrSH钢的变形处理，促进了连续冷却相变，相变区左移；随着冷却速度的降低，奥氏体变形程度的增加，连续冷却相变组织中先共析铁素体和珠光体体积百分数增多，金相组织细小，完全获得先共析铁素体+珠光体组织的临界冷却速度增大。22CrSH 钢中的MnS能均匀奥氏体晶粒，对奥氏体向先共析铁素体、贝氏体、WF及铁素体的相变有一定的促进作用。

22CrSH钢正火后的显微组织为块状铁素体+珠光体组织，夹杂物以硫化物为主，非金属夹杂物、晶粒度及低倍组织满足加工和使用要求；机械性能良好，断屑性能好，切削性能略好于28MnCr5。

22CrSH齿套、倒档惰轮渗碳和碳氮共渗后零件表面层硬度呈梯度分布，从表层至心部硬度变化平缓，心部硬度适中，与渗碳层相比，碳氮共渗层显微硬度略有升高，表面硬度稍大。经渗碳淬火后齿套、倒档惰轮表层组织为为针状马氏体加残余奥氏体；心部为板条马氏体；经碳氮共渗淬火后表层组织为马氏体+弥散分布的碳氮化合物+残余奥氏体；渗碳和碳氮共渗热处理后齿套外齿跨棒距和内齿跨棒距尺寸均略有增大。工件热处理变形是由热应力与组织应力综合作用的结果。渗碳和碳氮共渗热处理的齿套、倒档惰轮由于表层和心部化学成分、组织结构、冷却速度和淬火温度的不同，造成零件尺寸公差增大。

关键词 22CrSH钢；热处理工艺；微观组织；加工性能

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哈尔滨工业大学工程硕士学位论文

Abstract

The effect of austenitization temperature, deformation and cooling rate of new gear steel 22CrSH for gear case on phase transformation and phase microstructure, cutting properties and heat treatment process were investigated in the paper according to the problem of gear case of transmission part synchromessh part for 016 Red Flag car.

Austenite deformation of 22CrSH steel makes the phase transformation at high temperature improved, cooling rates that all kinds of phase transformatioms occurred increase and the beginning time of phase transformation shifts left. The critical cooling rate of fully pre-eutectoid ferrite and pearlite gains and improves the phase transformation of ferrite and pearlite with cooling rate decrease and the extent of austenite deformation increase, the volume percent of pre-eutectoid ferrite and pearlite gains, fine microstructures. MnS inclusion in 22CrSH steel can make austenite crystalline grain uniform and promote austenite transformation to pre-eutectoid ferrite, bainite, WF and pearlite to some extent.

Microstructure of 22CrSH steel after normalizing treatment is ferrite and pearlite and MnS is the main inclusion. Sulphide non-metallic inclusion, crystalline grain grade and low magnitude microstructure satisfy the requirement of process and application. Mechanical and broken metal fillings properties of 22CrSH steel are good. Cutting properties of 22CrSH steel are better a little than that of 28MnCr5 steel.

Surface layer hardness of gear case and reverse gear of 22CrSH steel after carburization and carbonitriding and quench changed gradually from external surface to the internal. The center area hardness is adaptive. Comparing with carburization layer the hardness of carbonitriding layer shifts slightly and surface hardness increases a little. Microstructure of carburization surface layer is needle-like martensite and residual austenite, the center area is slip austenite. Microstructure of carbonitriding surface layer is martensite + distributed carbon nitride compound + residual austenite. Over stick distance tolerance of external teeth and internal teeth of gear case after carburization and carbonitriding both

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哈尔滨工业大学工程硕士学位论文

increase. Heat treatment deformation of the parts is owed to thermal tress and phase stress affects each other. The parts size tolerance rises because surface layer and the center area have different microstructures, composites, coolling rates and quench temperatures after gear case and reverse gear carburization and carbonitriding. Heat treatment process i …… 此处隐藏：14696字，全部文档内容请下载后查看。喜欢就下载吧 ……