13913110212Application of vacuum heat treatment technology
Time:2023-12-01
Application of vacuum heat treatment technology
Due to a series of characteristics of vacuum heat treatment, this modern new process has been rapidly developed and widely used. From the treatment of materials, the process can deal with carbon steel, stainless steel, alloy steel, heat-resistant alloy, magnetic materials, titanium and titanium alloy, zirconium and zirconium alloy, tool steel (including die steel, cutting tool steel). From the point of view of the components of the product, the aircraft wing girder, landing gear, high degree bolts and other structural parts in the aviation industry, gear, shaft, tools, fixtures, molds and so on in mechanical manufacturing need to be vacuum heat treatment. From the application of the process field, in the machine, metallurgy, energy, transportation, aerospace, aviation, navigation, weapons, construction, light industry, textile, chemical, petroleum, electronics, electrical appliances and other industries need vacuum heat treatment. Vacuum heat treatment plays an important role in upgrading mechanical and electronic products, improving product quality, reducing consumption, playing the potential of materials, and improving product life
1. Vacuum annealing
Characteristics of vacuum annealing
Due to the degassing, degreasing and rust removal in vacuum heating, the gas dissolved in the metal is easily discharged, so the surface of the parts after vacuum annealing is clean and bright. During vacuum annealing, the deformed grains produced by pressure processing are restored, and new grains are formed, so that the microstructure is evenly refined, and the mechanical properties of the material are changed. After vacuum annealing, there is no trace of lubricant on the surface of the material, the surface is dry, and it can be directly electroplated without pickling or sandblasting, so as to achieve the purpose of shortening the process flow and improving the product quality. 1.3.1.2 Vacuum annealing application Scope
(1) Annealing of refractory metals. Molybdenum, tungsten, tantalum, cobalt, vanadium, zirconium and other metals melting point is very high, but also easy to oxidize, easy to be contaminated by refractory materials, in the processing degree and hardness is very high, if it contains hydrogen, oxygen, nitrogen and other gases, will make the material ductility becomes poor, in order to turn them into profiles, after vacuum annealing, softened these materials, and then pressure processing
(2) Annealing of soft magnetic alloy. Soft magnetic alloy is generally obtained by vacuum melting and vacuum rolling, because it also ensures stable magnetism under the action of temperature, pressure, radiation and mechanical load, so it needs to be treated with vacuum annealing
(3) Annealing of silicon steel sheet. In order to eliminate hydrogen, carbon monoxide, carbon dioxide, methane and other gases in the silicon steel sheet, remove oxides and sulfides, eliminate internal stress and grain boundary distortion, improve magnetic induction, and reduce unit iron loss, vacuum annealing is required.
(4) Annealing of iron-nickel alloy and iron-silicon alloy. The day is structured to improve resilience
(5) Annealing of electrical steel. The aim is to improve plasticity and uniform magnetism
(6) Annealing of stainless steel. The aim is to improve the resistance of stainless steel to intergranular corrosion
(7) Annealing of structural steel. The purpose is to improve the degree and surface brightness.
(8) Annealing of steel wire and thermocouple wire. The purpose is to obtain a bright surface, eliminate processing stress, and remove harmful gases such as nitrogen and oxygen contained in the wire
2. Vacuum quenching
The main purpose of vacuum quenching is to neutralize the quality of metal components, especially the quality of the surface layer. For tool steel, the vacuum quenching can ensure sufficient hardness requirements, and the surface brightness is good, the deformation is small, the hardness is high and the uniform service life is long, the post-processing process is simple, and the production cycle is short
After vacuum quenching, the surface brightness of the steel is due to the absence of oxide film on the supply surface, and the oil impurities attached to the supply surface are volatilized, thus making the surface of the metal parts shiny. Vacuum quenching is slow and uniform, and the workpiece does not have to move when cooled in place after gas quenching, so the deformation is small and regular. There is no oxidation and decarburization after vacuum quenching, and the high alloy tool steel will have an instantaneous carburizing on the highly active surface after vacuum heating during oil quenching due to the high temperature of quenching heating, forming a small layer of carburizing layer, so that the hardness after vacuum quenching is higher and uniform than that during ordinary quenching, and there will be no soft quenching point. The degassing effect during vacuum heating can improve the degree, wear resistance, anti-bite performance and fatigue of the material, so the life of the workpiece after vacuum quenching is generally higher.
3. Vacuum high pressure gas quenching
Vacuum high-pressure gas quenching is a process in which the workpiece to be treated is heated in the vacuum state, and then quickly cooled in the cooling gas with high pressure and high flow rate to improve the surface hardness of the workpiece to be treated. Vacuum high pressure gas quenching has obvious advantages compared with ordinary gas quenching, oil quenching, salt bath quenching:
① The workpiece surface quality is good, chemical, no carburization;
The quenching uniformity is good, the workpiece deformation is small;
③ The quenching degree is controllable, and the cooling speed can be controlled:
④ High productivity, eliminating the cleaning work after quenching;
There are many materials suitable for vacuum high pressure gas quenching, mainly: high-speed steel (such as cutting tools, metal molds, press molds, gauge jet engine bearings), tool steel (watch parts, fixtures, presses), die steel, bearing steel, etc.
4. Vacuum carburizing
Vacuum carburizing principle
Vacuum carburizing is to heat mechanical parts in vacuum, when the critical temperature of steel is above, stay for a period of time and degassing and removing the oxide film, and then pass through the purified carburizing gas (such as ch4, c3, h8, etc.) to carburize and diffusion. The vacuum carburizing temperature is high, up to 1030℃, and the carburizing speed is fast. The carburized parts are degassed and deoxidized to improve the surface activity, improve the subsequent diffusion speed, carburizing and diffusion repeatedly alternate until the required surface concentration and depth are reached.
Characteristics of vacuum carburizing
Vacuum carburizing depth and surface concentration can be controlled; Vacuum carburizing can change the metallurgical properties of metal parts surface. The effective carburizing depth of vacuum carburizing is better than that of other carburizing methods
5. Vacuum tempering
The purpose of vacuum tempering is to maintain the advantages of vacuum quenching (product no oxidation, no decarbonization, smooth surface, no corrosion pollution, etc.), if you do not use vacuum tempering, you will lose the advantages of vacuum quenching. The application of vacuum tempering is closely related to vacuum quenching. All mechanical parts after vacuum quenching, in order to reduce or eliminate the quenching stress, ensure the corresponding organizational transformation, improve the plasticity and toughness of the material, obtain hardness and degree, and stabilize the workpiece size and other process needs, must go through vacuum Tempering treatment.
Due to a series of characteristics of vacuum heat treatment, this modern new process has been rapidly developed and widely used. From the treatment of materials, the process can deal with carbon steel, stainless steel, alloy steel, heat-resistant alloy, magnetic materials, titanium and titanium alloy, zirconium and zirconium alloy, tool steel (including die steel, cutting tool steel). From the point of view of the components of the product, the aircraft wing girder, landing gear, high degree bolts and other structural parts in the aviation industry, gear, shaft, tools, fixtures, molds and so on in mechanical manufacturing need to be vacuum heat treatment. From the application of the process field, in the machine, metallurgy, energy, transportation, aerospace, aviation, navigation, weapons, construction, light industry, textile, chemical, petroleum, electronics, electrical appliances and other industries need vacuum heat treatment. Vacuum heat treatment plays an important role in upgrading mechanical and electronic products, improving product quality, reducing consumption, playing the potential of materials, and improving product life
1. Vacuum annealing
Characteristics of vacuum annealing
Due to the degassing, degreasing and rust removal in vacuum heating, the gas dissolved in the metal is easily discharged, so the surface of the parts after vacuum annealing is clean and bright. During vacuum annealing, the deformed grains produced by pressure processing are restored, and new grains are formed, so that the microstructure is evenly refined, and the mechanical properties of the material are changed. After vacuum annealing, there is no trace of lubricant on the surface of the material, the surface is dry, and it can be directly electroplated without pickling or sandblasting, so as to achieve the purpose of shortening the process flow and improving the product quality. 1.3.1.2 Vacuum annealing application Scope
(1) Annealing of refractory metals. Molybdenum, tungsten, tantalum, cobalt, vanadium, zirconium and other metals melting point is very high, but also easy to oxidize, easy to be contaminated by refractory materials, in the processing degree and hardness is very high, if it contains hydrogen, oxygen, nitrogen and other gases, will make the material ductility becomes poor, in order to turn them into profiles, after vacuum annealing, softened these materials, and then pressure processing
(2) Annealing of soft magnetic alloy. Soft magnetic alloy is generally obtained by vacuum melting and vacuum rolling, because it also ensures stable magnetism under the action of temperature, pressure, radiation and mechanical load, so it needs to be treated with vacuum annealing
(3) Annealing of silicon steel sheet. In order to eliminate hydrogen, carbon monoxide, carbon dioxide, methane and other gases in the silicon steel sheet, remove oxides and sulfides, eliminate internal stress and grain boundary distortion, improve magnetic induction, and reduce unit iron loss, vacuum annealing is required.
(4) Annealing of iron-nickel alloy and iron-silicon alloy. The day is structured to improve resilience
(5) Annealing of electrical steel. The aim is to improve plasticity and uniform magnetism
(6) Annealing of stainless steel. The aim is to improve the resistance of stainless steel to intergranular corrosion
(7) Annealing of structural steel. The purpose is to improve the degree and surface brightness.
(8) Annealing of steel wire and thermocouple wire. The purpose is to obtain a bright surface, eliminate processing stress, and remove harmful gases such as nitrogen and oxygen contained in the wire
2. Vacuum quenching
The main purpose of vacuum quenching is to neutralize the quality of metal components, especially the quality of the surface layer. For tool steel, the vacuum quenching can ensure sufficient hardness requirements, and the surface brightness is good, the deformation is small, the hardness is high and the uniform service life is long, the post-processing process is simple, and the production cycle is short
After vacuum quenching, the surface brightness of the steel is due to the absence of oxide film on the supply surface, and the oil impurities attached to the supply surface are volatilized, thus making the surface of the metal parts shiny. Vacuum quenching is slow and uniform, and the workpiece does not have to move when cooled in place after gas quenching, so the deformation is small and regular. There is no oxidation and decarburization after vacuum quenching, and the high alloy tool steel will have an instantaneous carburizing on the highly active surface after vacuum heating during oil quenching due to the high temperature of quenching heating, forming a small layer of carburizing layer, so that the hardness after vacuum quenching is higher and uniform than that during ordinary quenching, and there will be no soft quenching point. The degassing effect during vacuum heating can improve the degree, wear resistance, anti-bite performance and fatigue of the material, so the life of the workpiece after vacuum quenching is generally higher.
3. Vacuum high pressure gas quenching
Vacuum high-pressure gas quenching is a process in which the workpiece to be treated is heated in the vacuum state, and then quickly cooled in the cooling gas with high pressure and high flow rate to improve the surface hardness of the workpiece to be treated. Vacuum high pressure gas quenching has obvious advantages compared with ordinary gas quenching, oil quenching, salt bath quenching:
① The workpiece surface quality is good, chemical, no carburization;
The quenching uniformity is good, the workpiece deformation is small;
③ The quenching degree is controllable, and the cooling speed can be controlled:
④ High productivity, eliminating the cleaning work after quenching;
There are many materials suitable for vacuum high pressure gas quenching, mainly: high-speed steel (such as cutting tools, metal molds, press molds, gauge jet engine bearings), tool steel (watch parts, fixtures, presses), die steel, bearing steel, etc.
4. Vacuum carburizing
Vacuum carburizing principle
Vacuum carburizing is to heat mechanical parts in vacuum, when the critical temperature of steel is above, stay for a period of time and degassing and removing the oxide film, and then pass through the purified carburizing gas (such as ch4, c3, h8, etc.) to carburize and diffusion. The vacuum carburizing temperature is high, up to 1030℃, and the carburizing speed is fast. The carburized parts are degassed and deoxidized to improve the surface activity, improve the subsequent diffusion speed, carburizing and diffusion repeatedly alternate until the required surface concentration and depth are reached.
Characteristics of vacuum carburizing
Vacuum carburizing depth and surface concentration can be controlled; Vacuum carburizing can change the metallurgical properties of metal parts surface. The effective carburizing depth of vacuum carburizing is better than that of other carburizing methods
5. Vacuum tempering
The purpose of vacuum tempering is to maintain the advantages of vacuum quenching (product no oxidation, no decarbonization, smooth surface, no corrosion pollution, etc.), if you do not use vacuum tempering, you will lose the advantages of vacuum quenching. The application of vacuum tempering is closely related to vacuum quenching. All mechanical parts after vacuum quenching, in order to reduce or eliminate the quenching stress, ensure the corresponding organizational transformation, improve the plasticity and toughness of the material, obtain hardness and degree, and stabilize the workpiece size and other process needs, must go through vacuum Tempering treatment.
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