Supercharge Your Innovation With Domain-Expert AI Agents!

Method for preparing forged waste heat isothermal normalizing fine grain gear

A technology of isothermal normalizing and residual heat after forging, applied in heat treatment equipment, manufacturing tools, heat treatment furnaces, etc., can solve the problems of gear strength, plasticity and toughness reduction, gear steel austenite grain growth and other problems, and achieve refinement Grain size, avoid aging and growth, simplify the effect of preliminary heat treatment process

Pending Publication Date: 2022-08-02
南京钢铁有限公司
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Existing carburized gear steel usually needs isothermal normalizing, carburizing and other processes after forging. The carburizing temperature of the gear is low and the carburizing time is long. In order to shorten the time, it is usually necessary to increase the carburizing temperature of the gear. The austenite grains of gear steel will grow significantly at high temperature, resulting in a significant decrease in the strength, plasticity and toughness of the final gear

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] A method for preparing a fine-grained gear by isothermal normalizing with residual heat after forging. The specific steps are as follows: heat the gear steel to 1200°C, hold it for 30s, then forge it, and then use the cooling method of air cooling, control the cooling rate at 5.5°C / s to cool the forged gear to 600°C, hold it for 30 minutes, and then air-cool it. In the carburizing and quenching stage, the gear is carburized at 920°C, then cooled to 840°C, held for 45 minutes, cooled by quenching oil, and finally tempered at 200°C, tempering time is 3h, and air-cooled. The gear steel adopts 20CrMnTi, and its chemical composition, in mass percentage, is C: 0.20; Si: 0.17; Mn: 0.82; P: 0.023; S: 0.026; Cr: 1.10; Ni: 0.01; V: 0.025; Ti: 0.05; Nb: 0.032; Al: 0.015; N: 0.006; the balance is Fe and inevitable impurities. The final grain size grade of the gear is around 7.

Embodiment 2

[0016] A method for preparing a fine-grained gear by isothermal normalizing with residual heat after forging. The specific steps are as follows: heat the gear steel to 1250°C, hold it for 50s, then forge it, and then use the cooling method of air cooling, control the cooling rate at 4°C / s to cool the forged gear to 620°C, hold it for 35min, and then air-cool it. In the carburizing and quenching stage, the gears are carburized at 940°C, then cooled to 850°C, held for 45 minutes, cooled by quenching oil, and finally tempered at 200°C, tempering time is 3h, and air-cooled. The gear steel adopts 18CrNiMo7-6, and its chemical composition, in mass percentage, is C: 0.16; Si: 0.32; Mn: 0.45; P: 0.005; S: ≤ 0.005; Cr: 1.53; Ni: 1.46; Mo: 0.32; V : 0.024; Ti: 0.04; Nb: 0.043; Al: 0.012; N: 0.006; the balance is Fe and inevitable impurities. The final grain size grade of the gear is around 6.5.

Embodiment 3

[0018] A method for preparing a fine-grained gear by isothermal normalizing with residual heat after forging. The specific steps are as follows: firstly heat the gear steel to 1230°C, hold it for 40s, and then forge it, and then adopt the cooling method of mist cooling, control the cooling rate at 3°C / s to cool the forged gear to 650°C, hold it for 35min, and then air-cool it. In the carburizing and quenching stage, the gears are carburized at 940°C, then cooled to 860°C, held for 60 minutes, cooled by quenching oil, and finally tempered at 160°C with a tempering time of 3 hours and air cooling. The gear steel is 18CrNiMo7-6, and its chemical composition, in terms of mass percentage, is C: 0.17; Si: 0.32; Mn: 0.53; P: 0.008; S: 0.008; Cr: 1.56; Ni: 1.45; Mo: 0.26; V: 0.034; Ti: 0.032; Nb: 0.05; Al: 0.013; N: 0.006; the balance is Fe and inevitable impurities. The final grain size grade of the gear is around grade 6.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a forged afterheat isothermal normalizing fine grain gear preparation method, which comprises the steps of forging forming, afterheat isothermal normalizing, machining, carburizing and quenching and low-temperature tempering, and specifically comprises the following steps: firstly, heating gear steel to 1200-1250 DEG C, carrying out forging forming after heat preservation, and controlling the final forging temperature to be 1050-1100 DEG C; cooling is controlled through air cooling or fog cooling, the forged and formed gear is cooled to 550-650 DEG C, and the gear is air-cooled to the room temperature after heat preservation; machining is carried out, after machining is finished, the gear is heated to 900-940 DEG C for carburizing, after carburizing is finished, the gear is cooled to 820-860 DEG C, oil quenching cooling is carried out after heat preservation, and finally low-temperature tempering and air cooling are carried out. The isothermal normalizing process is carried out by fully utilizing the afterheat after gear forging, so that the production cost can be reduced, and the gear steel with uniform and fine tissues can be obtained.

Description

technical field [0001] The invention relates to a method for preparing gears, in particular to a method for preparing gears with residual heat after forging and isothermal normalizing fine-grained. Background technique [0002] The existing carburizing gear steel usually needs to be subjected to isothermal normalizing, carburizing and other processes after forging. Among them, the carburizing temperature of the gear is low and the carburizing time is long. In order to shorten the time, it is usually necessary to increase the carburizing temperature of the gear. At high temperature, the austenite grains of gear steel will grow significantly, resulting in a significant decrease in the strength, plasticity and toughness of the final gear. SUMMARY OF THE INVENTION [0003] Purpose of the invention: The present invention aims to provide a method for preparing a post-forging waste heat isothermal normalizing fine-grained gear which is beneficial to obtain uniform fine-structure ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): C21D9/32C21D1/18C21D1/28C21D8/00C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14C22C38/44C22C38/46C22C38/48C22C38/50C21D6/00
CPCC21D9/32C21D1/28C21D1/18C22C38/02C22C38/04C22C38/44C22C38/46C22C38/50C22C38/48C22C38/06C22C38/001C22C38/12C22C38/14C21D8/005C21D6/004C21D6/002C21D6/005C21D6/008C21D2211/009C21D2211/005C21D2211/001Y02P10/20
Inventor 周蕾李海洋彭学艺邓伟赵秀明鲍玉坤吴萌
Owner 南京钢铁有限公司
Features
  • R&D
  • Intellectual Property
  • Life Sciences
  • Materials
  • Tech Scout
Why Patsnap Eureka
  • Unparalleled Data Quality
  • Higher Quality Content
  • 60% Fewer Hallucinations
Social media
Patsnap Eureka Blog
Learn More

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2025 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com