Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Vacuum carburizing method for obtaining dispersed fine carbides

A dispersion distribution and vacuum carburizing technology, which is applied in the direction of solid-state diffusion coating, coating, heat treatment process control, etc., can solve the problems of harmful product performance, inability to obtain carbides, toughness of difficult materials, etc., to achieve strong practicability, Improving service performance and exerting the effect of toughness

Pending Publication Date: 2021-12-03
BEIJING RES INST OF MECHANICAL&ELECTRICAL TECH
View PDF8 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] like figure 1 , image 3 As shown, the above requirements cannot be achieved by using the current vacuum carburizing process, and the effective control of the size and shape of carbides can only be achieved at a low carbon content (below 0.8%). Once the carburized layer content is increased The amount of carbon often presents network carbides that are harmful to product performance, that is, carbon atoms are always precipitated at the austenite grain boundaries, but it is impossible to obtain carbides that nucleate, grow and form diffuse distributions in the austenite grains , it is difficult to maximize the strength and toughness of the material

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

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Vacuum carburizing method for obtaining dispersed fine carbides
  • Vacuum carburizing method for obtaining dispersed fine carbides
  • Vacuum carburizing method for obtaining dispersed fine carbides

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] see figure 2 , in an embodiment of the present invention, a vacuum carburizing method for obtaining dispersed fine carbides, comprising the following stages:

[0046] (1) Heating and heat preservation stage: Determine whether the heating process is segmented according to the material and size of the workpiece, and set the heating temperature, heating time, and holding time of each segment. After the process curve is compiled, the workpiece is placed in a vacuum furnace to evacuate and run for heating. The final carburizing temperature is usually 930-980°C.

[0047] (2) Pulse carburizing stage: According to the carburizing layer depth of the workpiece or the carbon concentration gradient requirements of the carburizing layer, set the number of carburizing / diffusion alternate operations and the time of each operation, and compile them in the process curve. The carburizing gas is pulsed into the carburizing chamber. The gas type is usually acetylene or propane. The carbu...

Embodiment 2

[0052] Dimensions (mm): shaft diameter φ38, length 150mm

[0053] Material: 18CrNiMo7-6.

[0054] Heat treatment technical requirements: standard JB / T6141.3-1992 vacuum carburized carburized layer carbide ≤ 2 grades, surface martensite and retained austenite ≤ 2 grades, carburized layer 0.9 ~ 1.2mm, surface hardness above HRC62 .

[0055] Carburizing process: The traditional process of vacuum low-pressure carburizing is compared with the vacuum carburizing process of obtaining dispersed fine carbides.

[0056] Using the traditional vacuum low-pressure carburizing process, the surface hardness of the test piece is HRC58.5, the surface carbon content is 1.5%, and the effective hardened layer depth is 1.1mm. Carbide grade 4, in the form of a network, such as image 3 shown.

[0057] Using the traditional vacuum low-pressure carburizing process, once the carbon content of the carburized layer is increased, the harmful structure of network carbide often forms on the surface, an...

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

PropertyMeasurementUnit
Shaft diameteraaaaaaaaaa
Lengthaaaaaaaaaa
Depthaaaaaaaaaa
Login to View More

Abstract

The invention discloses a vacuum carburizing method for obtaining dispersed fine carbides. The vacuum carburizing method comprises a heating and heat preservation stage, a pulse carburizing stage, a temperature changing stage and a quenching stage; the pulse carburizing stage refers to a high-concentration carburizing process in which carburizing and diffusion are alternated for multiple times; in the temperature changing stage, after carburizing is finished, heating is stopped, air inflation and rapid cooling are carried out to reach a certain temperature below the Ac1 line, in addition, heat preservation is carried out for a period of time, then the temperature is immediately increased to the quenching temperature, namely 30-50 DEG C above the Ac3 line or the Ac1 line, and heat preservation is carried out till a workpiece is uniformly austenitized; and the quenching stage is carried out by adopting one of high-pressure gas quenching or oil quenching. According to the vacuum carburizing method, the structure can be refined, meanwhile, the surface carbon content is increased, the dispersed fine carbides (mainly spherical) are obtained, the obdurability of the material is exerted to the maximum degree, and therefore the service performance of the workpiece is improved.

Description

technical field [0001] The invention relates to a vacuum carburizing heat treatment technology, in particular to a vacuum carburizing method for obtaining dispersed fine carbides. Background technique [0002] Heat treatment is a process technology that gives or improves the service performance of the workpiece by changing the microstructure inside the workpiece, or changing the chemical composition of the workpiece surface, and fully exploits the potential of the material. Heat treatment is a key core technology in the machinery manufacturing industry. With the continuous emphasis on heat treatment technology, the heat treatment industry has gradually developed from extensive to refined, and more attention has been paid to new processes, new technologies, improving product intrinsic quality, saving energy, reducing consumption and prolonging life. Focus on economic benefits, etc. Vacuum low-pressure carburizing technology gradually replaces controllable atmosphere carburiz...

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): C23C8/20C21D1/18C21D1/773C21D11/00
CPCC23C8/20C21D1/18C21D11/005C21D1/773
Inventor 丛培武徐跃明杜春辉陆文林陈旭阳何龙祥王赫薛丹若杨广文范雷凡占稳
Owner BEIJING RES INST OF MECHANICAL&ELECTRICAL TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

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

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com