What Is the Cryogenic Treatment Process?
Knowledge

What Is the Cryogenic Treatment Process?

Low-temperature treatment is a sub-zero process, which is carried out immediately after quenching and is carried out by continuous tempering. The ultra-cold treatment has a significant improvement in the wear strength of the workpiece and has a breakthrough benefit for the stability of the mold size.
Published: May 05, 2021
What Is the Cryogenic Treatment Process?

With the continuous development and innovation of the machinery industry, the requirements for the precision of metal materials are getting higher and higher. How to improve the mechanical properties and service life of metal workpieces is a technology that the manufacturing industry wants to breakthrough. After the heat treatment process, the hardness and mechanical properties of the steel are greatly improved, but after the heat treatment, the following problems are still encountered:

  1. Residual Austenite. The ratio is about 10%-20%. Because Austenite is very unstable, it is easy to transform into Martensitic when subjected to external force or environmental temperature changes, which will cause irregular expansion of the material and reduce the dimensional accuracy of the workpiece.
  2. The structure has coarse grains, and the material carbides are solid solution and supersaturated.
  3. Residual internal stress. The residual internal stress after heat treatment will reduce the fatigue strength and other mechanical properties of the material, and easily lead to deformation of the workpiece during the stress release process.

And through the application of cryogenic and ultra-cryogenic treatment technology, it will be improved.

What is the cryogenic treatment?


Low temperature treatment is a metal treatment that enhances and enhances the mechanical properties of metal materials by using low temperature. Placing the workpiece at a temperature below -190°C can improve properties such as wear resistance and stability.

Cryogenic treatment is a post-heat treatment process that treats the metal at -100°C so that almost all the soft residual Austenite is converted into high-strength Martensitic, and can reduce surface looseness and surface roughness. When this process is completed, it will not only the surface can almost increase the strength, wear resistance, toughness, and other performance indicators of the entire metal, so that the molds and tools will still have high wear resistance and high strength after several refurbishments, and the life will be doubled. increase. The service life of knife and scissors products that have not undergone cryogenic treatment will be significantly reduced after refurbishment. Cryogenic treatment is not only applied to knife and scissors products, but also can be applied to the molds for making knife and scissors products, and can also significantly increase the life of the mold.

Principles of cryogenic treatment technology

  1. Eliminate retained austenite:
    Generally, the residual Austenite after quenching and tempering is about 8-20%. The residual Austenite will be further Martensitic over time. During the Martensitic transformation process, it will cause volume expansion, which will affect the dimensional accuracy and make the lattice interior the increase in stress seriously affects the performance of the metal. Cryogenic treatment can generally reduce the residual Austenite to less than 2% and eliminate the influence of the residual Austenite. If there is more residual Austenite, the strength will be reduced. Under the action of cyclic stress, it is easy to fatigue and falls off, causing nearby carbide particles to hang in the air, and quickly fall off with the matrix to produce spalling pits, forming a relatively rough surface.
  2. Fill the internal gaps to increase the metal surface area, namely the wear-resistant surface:
    Cryogenic treatment enables Martensitic to fill the internal voids, make the metal surface denser, increase the wear-resistant area, smaller crystals, increase the depth of the quenching layer, increase the number of renovations, increase the stability, and increase the life of materials and objects.
  3. Precipitation of carbide particles:
    Cryogenic treatment not only reduces the residual Martensitic but also precipitates carbide particles. The shrinkage of martensite during the cryogenic process forces the reduction of the crystal lattice and drives the precipitation of carbon atoms. Moreover, because the diffusion of carbon atoms is difficult at low temperatures, the size of the carbides formed is up to Nanometer level and attached to the Martensitic twin belt, increase the hardness and toughness. Cryogenic treatment can transform most of the residual Austenite into Martensitic, and precipitate carbide particles in Martensitic, accompanied by the refinement of the matrix structure.
  4. Reduce residual stress
  5. Make the metal matrix more stable
  6. Increase the strength and toughness of metal materials
  7. Increase the metal hardness by about HRC1~2
  8. Increased redness

Cryogenic process: Cryogenic treatment is carried out in three stages: cooling, heat preservation, and heating.

  1. Cooling stage
    The purpose of slow cooling is to eliminate residual stress. Because in the process of quenching and tempering, residual stress will be generated in the metal matrix. In the process of residual Austenite transforming to Martensitic, the volume expansion will also increase the residual stress. Only by slow cooling can the increase in residual stress be offset. And eliminate residual stress. The residual stress in the matrix is generally ignored, but it is the residual stress in the matrix that causes defects such as cracks in the knife and scissors products. The rapid cooling will increase the residual stress.
  2. Insulation stage
    The purpose of heat preservation is to make all the residual Austenite in the matrix turn into Martensitic as much as possible, and produce as many carbide particles as possible, because the process of residual Austenite to Martensitic is a slow process, and the length of the heat preservation time will affect the residual austenite. The amount of the transformation of the intensification and the life after deep cooling is mainly determined by the length of the holding time. Normally, the performance of holding for 2 to 4 hours has been improved, but if it is a high-quality product, you need to use 24 For the holding time of more than hours, the life-span improvement multiple is directly related to the length of the holding time.
  3. Heating stage
    The main purpose of the slow heat process is to prevent the generation of residual stress.

The best time for cryogenic treatment

It is generally believed that cryogenic treatment should have the best effect within two hours of quenching the workpiece, because the residual Austenite will gradually transform to Martensitic over time, and the transformed Martensitic will solidify, thereby reducing the ability to precipitate carbides.

Factors affecting the cryogenic effect:

  • The same cryogenic treatment process has different effects due to different materials
  • The same cryogenic treatment process has different effects due to different workpiece shapes
  • The lower the temperature, the better the effect
  • The longer the time, the better the effect
  • After cryogenic treatment, the corrosion resistance of the material is improved
Application of cryogenic treatment technology:

Cryogenic treatment can increase the wear resistance of tools and molds, and the cryogenic treatment process is applied to molds, knives, scissors, and measuring tools. Many professional cryogenic treatment plants use ready-made processes to perform cryogenic treatment for customers to improve the quality of their products.

Published by May 05, 2021 Source :kknews

Further reading

You might also be interested in ...

Headline
Knowledge
What Do You Know About Planetary Reducer?
Planetary reducer has been in existence for more than 30 years. During this long period of time, planetary reducer has gradually entered the field of automation from only appearing in high-end equipment in Europe and America, and has been widely used in machine tools, semiconductors, and packaging industries in recent years. The equipment in the medical food industry, aerospace and other fields will be used with planetary reducers. High, medium and low power servo motors with planetary reducers have become standard. What are the applications and advantages of planetary reducers? This article will let you know more about planetary reducers.
Headline
Knowledge
What are the Classifications of Packaging Equipment?
Packaging involves all walks of life. Manufacturers that produce physical products and need to enter the circulation field all need packaging processes, especially in light industry, and packaging equipment is indispensable. With the development of all walks of life, more and more industries use packaging equipment to reduce the labor intensity of the packaging process, improve product quality, reduce investment costs, and improve the labor environment. In the following, we are going to learn more about the common classifications of packaging equipment.
Headline
Knowledge
Safety and Use of Woodworking Machinery
Woodworking machine, as the name suggests, is the mechanical equipment used in wood processing. It is a variety of cutting and processing equipment used in the process of sawing logs and processing them into wood products, and furniture machinery is an important part of woodworking machinery. Woodworking machines are the same as machine tools, and can be divided into milling machines, lathes, planers, drilling, rotary cutting, sanding, etc. according to different processing methods. However, do you understand the safety and use of woodworking machinery? Check out the following.
Headline
Knowledge
What is the Importance of Lithography Technology and Mask Aligner in Chip Manufacturing?
Lithography is the most important processing technology of integrated circuits and the most critical technology for manufacturing chips. In the entire chip manufacturing process, the implementation of almost every process is inseparable from the technology of lithography.
Headline
Knowledge
What is A Switching Power Supply? Through Principal Analysis, Understand the Basics In 3 Minutes!
Many people do not know about switching power supply and have always thought that is similar to a linear power supply. Actually, there is difference. The following will explain the principles of basic regarding switching power supplies. Learn with us now!
Headline
Knowledge
Basics to An Electronic Connector
Electronic connectors are also often referred to as circuit connectors, electrical connectors, and conductor devices that bridge two conductors on a circuit so that current or signals can flow from one conductor to another. An electronic connector is a motor system that can provide a separable interface to connect two secondary electronic systems. Simply put, the components used to complete the electrical connection between circuits or electronic machines are called connector.
Headline
Knowledge
What is A KVM Switch?
KVM switches allow you to control multiple computers from a single keyboard, monitor and mouse, increasing productivity, saving space and money. This exclusive feature also provides IT administrators with multiple computers or servers, centralized real-time updates and maintenance.
Headline
Knowledge
Common Hand Tools in Our Daily life
Hand tools can be divided into wrenches, pliers, screwdrivers, etc. according to their uses, which are used to assist the assembly, maintenance, or tightening and loosening needs of machines or objects.
Headline
Knowledge
What is A Five-Axis Machine Tool?
Five-axis CNC machining means that there are at least five coordinate axes (three linear coordinates and two rotary coordinates) on a machine tool, and can be processed simultaneously with coordinated movements under the control of the computer numerical control system. The axis of the CNC machine tool means the motion axis, which is actually a coordinate axis in space, such as the XY axis of the coordinates. There is no motion axis with an independent controller and motor drive system.
Headline
Knowledge
What is the Lathe Manufacturing Process? Understand the Processing Methods and Components of Lathes
Lathe machines are used to remove excess material from a workpiece to give the workpiece the desired shape and size. Machining process designed for precision machining of relatively hard materials.
Headline
Knowledge
Forward-Looking Technology of End-to-End Encrypted Communication Protocol
When you chat with friends or family members using communication software, the information may be intercepted when transmitted on the Internet, thereby exposing the chat content. If the content contains confidential information, it may endanger privacy and security. End-to-end encryption (E2EE) is a method of protecting data that prevents potential eavesdroppers from monitoring data in transit.
Headline
Knowledge
Introduction to Types of Forklifts
The forklift is one of the most convenient tools and equipment for modern warehousing and logistics transportation. So, are you wondering what types of forklifts are there? What are the characteristics of various types of forklifts? Before purchasing a forklift, you must know the types of forklifts, and evaluate the use environment and usage before making a decision. This article will bring you an introduction to the types of forklifts, making it easier for you to choose one!
Agree