Can tempering lead to decarbonization? Is annealing decarburization related to the furnace tank

1) Tempering can lead to decarburization.

2) Cause: The "decarburization" of steel parts during the heating process refers to the burning of the carbon in the surface layer of the workpiece in a red-hot (to varying degrees) state. We all have the experience that at night, when the lights are dim, the parts are heated to about 580 degrees Celsius.

You can see the dark red. At this point, there are conditions for the carbon to be burned. Therefore, the high-temperature tempering of steel parts can actually both produce oxide scale and decarburize.

Decarburization is a phenomenon in which the carbon content of the surface of steel decreases when heated. The process of decarburization is when the carbon in the steel reacts with hydrogen or oxygen at high temperatures to produce methane or carbon monoxide.

Tempering should have the potential to lead to decarburization, and if it is high-temperature tempering and improper protection, the conditions for decarbonization are met. With the conditions for decarburization, whether it is quenching, tempering, normalizing, or annealing, decarburization should occur. Personal opinion, experts, please correct.

Tempering generally does not lead to decarburization, and oxidation channels are possible.

Hello dear, glad to answer for you. Annealing decarburization is related to furnace tanks. Furnace tank refers to the equipment used to carry and heat metal materials during the production, manufacturing, processing and storage of metal materials.

In the process of metal material processing, it is necessary to heat, cool and adjust the metal structure of metal materials, and the furnace tank is the main equipment to provide a heating environment. Annealing and decarburization is a common metalworking process that alters the physical and chemical properties of metals by heating and cooling them at high temperatures through equalization cracking. In the annealing and decarburization process, the role of the furnace tank is to provide a constant temperature heat treatment environment.

The metal material is placed in the furnace tank, and then heated to the required temperature, maintained for a certain period of time, so that the structure of the metal material reaches a certain transformation, and then cooled to room temperature. The model and specification of the furnace must meet the required process parameters and the requirements of the metal material to ensure the ideal processing results. Therefore, annealing decarburization and furnace tanks are closely related.

In the process of metal material processing, it is necessary to select the appropriate furnace tank according to the properties and requirements of the metal material, and control the heating, dry and cold insulation and cooling process in the furnace to achieve the ideal annealing and decarburization effect.

Decarburization annealing refers to the phenomenon of reducing the carbon content of the surface of steel when it is subjected to high temperatures.

I haven't heard of decarburization annealing, but annealing can cause decarburization, which is generally something we don't want.

Decarburization refers to the phenomenon of decreasing the carbon content of steel, which is called decarburization.

Decarburization is the result of diffusion, and on the one hand, oxygen diffusion into the steel is the result of decarburization; On the other hand, the carbon in steel diffuses outward. In the end, the decarburization layer can only be formed when the rate of decarburization exceeds the rate of oxidation.

When the oxidation rate is very large, no obvious decarburization phenomenon can occur, that is, the iron is oxidized to form iron oxide scale after the decarburization layer is generated. As a result, in an atmosphere with relatively weak oxidation, a deep decarburization layer can be formed.

For the vast majority of steel materials, the decarburization phenomenon will lead to the deterioration of the performance of the steel material, so the decarburization layer is regarded as a defect of the steel material, especially for some special steels (such as tool steel, bearing steel, high-speed steel, etc.), the decarburization layer is a serious impact on its performance.

The carbon content of the decarburized layer is lower than that of the normal structure in the chemical composition, the amount of cementite (Fe C) in the decarburization layer is less than that in the normal structure, and the strength and hardness of the decarburized layer are lower than those in the normal structure.

The principle of decarburization is basically the same, mainly due to the redox reaction between the carbon element and other components in the surrounding medium, resulting in the loss or reduction of carbon in the steel. If this happens, if carburizing can be done, carburizing or carburizing can be tried, and if it can't be repaired, scrapping can be considered when the accuracy of the finished product or the use conditions cannot be achieved.

First of all, let's talk about what kind of material is decarburized, and secondly, what kind of furnace type do you use, and what is the protective atmosphere? We're going on a discussion. Oh, if the hardness is not enough, the metallographic is not enough, and it can be inferred whether it is decarburized. Metallographic prevails.

How to spot: Hardness testing reveals low surface hardness, or metallographic inspection reveals ferrite on the surface of the part. Severe decarburization is accompanied by oxide scale on the surface of the part.

How to deal with it after discovery: if it is not serious, it can be turned off, or carbonized; If it's serious, it's scrapped.

Oxidation is the reaction between iron atoms and oxides in steel, and decarburization is the reaction between carbon atoms in steel and the gas in the furnace.

The phenomenon of oxidation reaction between the surface of steel and the oxygen in the furnace air during heat treatment to form oxides is called oxidation.

The carbon on the surface of the steel in the heat treatment process obtains a certain amount of energy and then leaves the surface layer and enters the furnace atmosphere, so that the surface carbon content decreases The phenomenon is called decarburization.

Summary. Carburizing is a commonly used surface treatment method that improves the corrosion and wear resistance of metal surfaces, thereby increasing the durability of metal surfaces. In the case of annealing with an oxide layer, carburizing will thin the oxide layer, which will affect the properties of the metal surface.

The solutions to this problem are:1Before carburizing, deoxidation treatment is carried out to remove the oxide layer, so as to improve the effect of carburizing.

2.In the carburizing process, a low-temperature carburizing process is used to reduce the thinning of the oxide layer. 3.

After carburizing, surface treatment techniques such as heat treatment, polishing, etc., are used to restore the properties of the metal surface. 4.After carburizing, surface coating technologies such as electroplating, coatings, etc., are used to improve the corrosion resistance and wear resistance of the metal surface.

The above are the methods and practices to solve the problem of re-carburizing of annealed oxide layer, I hope it can help you.

Originally, there was an oxide layer in the annealing, but what would happen if it was re-carburized.

Carburizing is a commonly used surface tuber punching method, which can improve the corrosion resistance and wear resistance of metal surfaces, thereby improving the durability of metal surfaces. In the case of annealing with an oxide layer, carburizing will thin the oxide layer, which will affect the properties of the metal surface. The solutions to this problem are:

1.Before carburizing, deoxidation treatment is carried out to remove the oxide layer, so as to improve the effect of carburizing. 2.

In the carburizing process, Bihong uses a low-temperature carburizing process to reduce the thinning of the oxide layer. 3.After carburizing, surface treatment techniques such as heat treatment, polishing, etc., are used to restore the properties of the metal surface.

4.After carburizing, surface coating technologies such as electroplating, coatings, etc., are used to improve the corrosion resistance and wear resistance of the metal surface. The above are the methods and practices to solve the problem of re-carburizing of annealed oxide layer, I hope it can help you.

Excuse me, but please go into more detail?

Carburizing is a commonly used surface tuber punching method, which can improve the corrosion resistance and wear resistance of metal surfaces, thereby improving the durability of metal surfaces. In the case of annealing with an oxide layer, carburizing will thin the oxide layer, which will affect the properties of the metal surface. The solutions to this problem are:

1.Before carburizing, deoxidation treatment is carried out to remove the oxide layer, so as to improve the effect of carburizing. 2.

In the carburizing process, Bihong uses a low-temperature carburizing process to reduce the thinning of the oxide layer. 3.After carburizing, surface treatment techniques such as heat treatment, polishing, etc., are used to restore the properties of the metal surface.

4.After carburizing, surface coating technologies such as electroplating, coatings, etc., are used to improve the corrosion resistance and wear resistance of the metal surface. The above are the methods and practices to solve the problem of re-carburizing of annealed oxide layer, I hope it can help you.

Reason: The carbon potential of the atmosphere is low during the diffusion period of the carburizing process;

The cooling section is not protected by atmosphere;

The furnace temperature is too high, resulting in oxidation and decarburization;

High temperature tempering temperature is too high;

When reheating and quenching, no gas stimulation protection is carried out;

If the quenching time is too long, it should be inspected.

Therefore, preventing the decarburization of the surface layer of the workpiece is not a one-sided process measure, but requires comprehensive by-pure quality control of the entire process.

Ways to prevent decarburization: Decarburization, by its very nature, is the contact of carburized workpieces at high temperatures during post-processing.

Oxidation. or low carbon potential).

atmosphere. Therefore, try to avoid high temperatures throughout the process.

Reasons: (1) The carbon potential of the atmosphere is low during the diffusion period of the carburizing process;

2) The cooling section is not protected by atmosphere;

3) Oxidation and decarburization caused by high furnace temperature;

4) High temperature tempering temperature is too high;

5) No atmosphere protection is carried out during reheating and quenching;

6) The residence time is too long during quenching.

Therefore, preventing the decarburization of the surface layer of the workpiece is not something that can be solved by unilateral process measures, and requires comprehensive quality control of the entire process.

Methods to prevent decarburization: Decarburization, by its very nature, is caused by the exposure of carburized workpieces to an oxidizing (or low-carbon potential) atmosphere at high temperatures during post-processing. Therefore, try to avoid high temperatures throughout the process.