METAL HEAT TREATMENT

Definition of heat treatment:

Heat treatment refers to a metal thermal processing process in which the material is in a solid state by means of heating, heat preservation and cooling to obtain the desired structure and properties. It’s a kind of Metallurgical Services that combination of heating & cooling operation timed & applied to a metal or alloy in the solid state in a way that will produce desired properties. Including: Annealing, Austempering, Carbonitriding, Carburizing, Case Hardening, Conventional Hardening (Quench & Temper), Homogenizing, Hydrogen Relief Baking, Martempering, Normalizing, Precipitation Hardening / Aging, Preheating / Weld Preheat, Shot Peening / Blasting, Solution Treating, Spheroidizing, Stabilizing / Cryogenic Treating, Stress Relieving, Other

What are the common heat treatment processes?

Normalizing: The heat treatment process of heating the steel or steel parts to an appropriate temperature above the critical point AC3 or ACM for a certain period of time and then cooling in the air to obtain a pearlite structure.
Annealing: The hypoeutectoid steel workpiece is heated to 20-40 degrees above AC3, and after holding for a period of time, it is slowly cooled with the furnace (or buried in sand or cooled in lime) to a heat treatment process of below 500 degrees and cooled in air.
Solution heat treatment: heat treatment process in which the alloy is heated to a high temperature single-phase region and maintained at a constant temperature, so that the excess phase is fully dissolved into the solid solution, and then rapidly cooled to obtain a supersaturated solid solution.
Aging: After solution heat treatment or cold plastic deformation, the properties of alloys change with time when they are kept at room temperature or slightly higher than room temperature.
Solution treatment: Fully dissolve various phases in the alloy, strengthen the solid solution, improve toughness and corrosion resistance, eliminate stress and soften, so as to continue processing and forming.
Aging treatment: Heating and maintaining the temperature at the precipitation temperature of the strengthening phase, so that the strengthening phase is precipitated, hardened, and the strength is improved.
Quenching: A heat treatment process in which the steel is austenitized and then cooled at an appropriate cooling rate, so that the workpiece can undergo martensite and other unstable microstructure transformations in all or a certain range of the cross section.
Tempering: A heat treatment process in which the quenched workpiece is heated to an appropriate temperature below the critical point AC1 for a certain period of time, and then cooled by a method that meets the requirements to obtain the required structure and properties.
Carbonitriding of steel: Carbonitriding is the process of simultaneously infiltrating carbon and nitrogen into the surface of steel. Medium temperature gas carbonitriding and low temperature gas carbonitriding (ie gas soft nitriding) are widely used. The main purpose of medium temperature gas carbonitriding is to improve the hardness, wear resistance and fatigue strength of steel. Low-temperature gas carbonitriding is mainly nitriding, and its main purpose is to improve the wear resistance and seizure resistance of steel.
Quenching and tempering: It is generally customary to combine heat treatment with quenching and high temperature tempering as quenching and tempering. Quenching and tempering treatment is widely used in various important structural parts, especially those connecting rods, bolts, gears and shafts that work under alternating loads. After quenching and tempering treatment, the tempered sorbite structure is obtained, and its mechanical properties are better than the normalized sorbite structure with the same hardness. Its hardness depends on the high temperature tempering temperature and is related to the tempering stability of the steel and the size of the workpiece section, generally between HB200-350.
Brazing: A heat treatment process in which two workpieces are heated, melted and bonded together with brazing filler metal.
Spheroidizing treatment: a process of treating alloy liquid in cast iron to obtain spheroidal graphite, thereby improving the mechanical properties of cast iron, which is called ductile iron. There are many kinds of spheroidizing process, such as punching method, bell jar method, wire feeding method and so on. Nodulizer According to the requirements of the obtained matrix, there are different nodulizers. The spheroidizing treatment makes the graphite in the spheroidal cast iron spherical, with high strength, good plasticity and toughness. Its comprehensive mechanical properties are close to steel, and it is widely used in industry because of its good casting properties, low cost and convenient production. Nodularizing treatment is required when producing ductile iron, that is, adding a certain amount of spheroidizer and inoculant to molten iron to obtain fine and uniformly distributed spheroidal cast iron.

Process characteristics:

Metal heat treatment is one of the important processes in machinery manufacturing. Compared with other processing processes, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but changes the microstructure inside the workpiece or changes the chemical composition of the workpiece surface. , to give or improve the performance of the workpiece. It is characterized by improving the intrinsic quality of the workpiece, which is generally not visible to the naked eye. In order to make the metal workpiece have the required mechanical properties, physical properties and chemical properties, in addition to the reasonable selection of materials and various forming processes, heat treatment process is often essential. Steel is the most widely used material in the machinery industry. The microstructure of steel is complex and can be controlled by heat treatment. Therefore, heat treatment of steel is the main content of metal heat treatment. In addition, aluminum, copper, magnesium, titanium, etc. and their alloys can also be heat treated to change their mechanical, physical and chemical properties to obtain different performance.

Thermal process：

Crafting process

The heat treatment process generally includes three processes of heating, heat preservation and cooling, and sometimes there are only two processes of heating and cooling. These processes are interconnected and uninterrupted. Heating is one of the important processes of heat treatment. There are many heating methods for metal heat treatment. The earliest ones used charcoal and coal as heat sources, and more recently, liquid and gas fuels were used. The application of electricity makes heating easy to control and free of environmental pollution. These heat sources can be used for direct heating or indirect heating through molten salt or gold, or even floating particles. When the metal is heated, the workpiece is exposed to the air, and oxidation and decarburization often occur (that is, the carbon content on the surface of the steel part is reduced), which has a very adverse effect on the surface properties of the parts after heat treatment. Therefore, the metal should usually be heated in a controlled atmosphere or protective atmosphere, in molten salt and in vacuum, and can also be protected by coating or packaging methods. The heating temperature is one of the important process parameters of the heat treatment process. The selection and control of the heating temperature are the main issues to ensure the quality of the heat treatment. The heating temperature varies with the metal material to be processed and the purpose of the heat treatment, but generally it is heated above the phase transition temperature to obtain a high-temperature structure. In addition, the transformation takes a certain time. Therefore, when the surface of the metal workpiece reaches the required heating temperature, it must be maintained at this temperature for a certain period of time to make the internal and external temperatures consistent and the microstructure changes completely. This period of time is called the holding time. When high-energy density heating and surface heat treatment are used, the heating speed is extremely fast, and generally there is no holding time, while the holding time of chemical heat treatment is often longer.
Cooling is also an indispensable step in the heat treatment process. The cooling method varies with different processes, mainly controlling the cooling rate. Generally, the cooling rate of annealing is the slowest, the cooling rate of normalizing is faster, and the cooling rate of quenching is faster. However, there are also different requirements due to different steel types. For example, hollow-hardened steel can be hardened with the same cooling rate as normalizing.

Process classification

Metal heat treatment process can be roughly divided into three categories: overall heat treatment, surface heat treatment and chemical heat treatment. According to the different heating medium, heating temperature and cooling method, each category can be divided into several different heat treatment processes. The same metal adopts different heat treatment processes to obtain different structures and thus have different properties. Steel is the most widely used metal in industry, and the microstructure of steel is also the most complex, so there are many types of steel heat treatment processes. The overall heat treatment is a metal heat treatment process that heats the workpiece as a whole, and then cools it at an appropriate rate to obtain the required metallographic structure to change its overall mechanical properties. The overall heat treatment of steel generally has four basic processes: annealing, normalizing, quenching and tempering.

Craftsmanship

Annealing is to heat the workpiece to an appropriate temperature, adopt different holding times according to the material and workpiece size, and then slowly cool it, the purpose is to make the internal structure of the metal reach or close to the equilibrium state, obtain good process performance and performance, or for further quenching Prepare for organization. Normalizing is to heat the workpiece to a suitable temperature and then cool it in the air. The effect of normalizing is similar to that of annealing, but the obtained structure is finer. It is often used to improve the cutting performance of materials, and is sometimes used for some parts with low requirements. as the final heat treatment. Quenching is to rapidly cool the workpiece in a quenching medium such as water, oil or other inorganic salts and organic aqueous solutions after heating and keeping the workpiece warm. After quenching, the steel becomes hard, but at the same time becomes brittle. In order to eliminate the brittleness in time, it is generally necessary to temper in time. In order to reduce the brittleness of steel parts, the quenched steel parts are kept at an appropriate temperature higher than room temperature but lower than 650 ° C for a long time, and then cooled. This process is called tempering.

Annealing, normalizing, quenching, and tempering are the “four fires” in the overall heat treatment. Among them, quenching and tempering are closely related and are often used together, and neither is indispensable. The “four fires” have evolved different heat treatment processes with different heating temperatures and cooling methods. In order to obtain a certain strength and toughness, the process of combining quenching and high temperature tempering is called quenching and tempering. After some alloys are quenched to form a supersaturated solid solution, they are kept at room temperature or a slightly higher appropriate temperature for a long time to improve the hardness, strength or electrical and magnetic properties of the alloy. Such a heat treatment process is called aging treatment. The method of combining pressure deformation and heat treatment effectively and closely to make the workpiece obtain good strength and toughness is called deformation heat treatment; heat treatment in a negative pressure atmosphere or vacuum is called vacuum heat treatment, which not only makes The workpiece is not oxidized or decarburized, the surface of the workpiece after treatment is kept smooth, and the performance of the workpiece is improved. Surface heat treatment is a metal heat treatment process that only heats the surface of the workpiece to change the mechanical properties of the surface. In order to only heat the surface layer of the workpiece without allowing too much heat to pass into the inside of the workpiece, the heat source used must have a high energy density, that is, a larger amount of heat energy is given to the workpiece per unit area, so that the surface layer or local area of the workpiece can be short-term or instantaneous. reach high temperature. The main methods of surface heat treatment are flame quenching and induction heating heat treatment. Commonly used heat sources are flames such as oxyacetylene or oxypropane, induced current, laser and electron beam. Chemical heat treatment is a metal heat treatment process that changes the chemical composition, structure and properties of the workpiece surface. The difference between chemical heat treatment and surface heat treatment is that the former changes the chemical composition of the surface of the workpiece. Chemical heat treatment is to heat the workpiece in a medium (gas, liquid, solid) containing carbon, salt or other alloying elements, and keep it for a long time, so that the surface layer of the workpiece is infiltrated with elements such as carbon, nitrogen, boron and chromium. After the elements are infiltrated, other heat treatment processes such as quenching and tempering are sometimes carried out. The main methods of chemical heat treatment are carburizing, nitriding, and metalizing. Heat treatment is one of the important processes in the manufacture of mechanical parts and tools. Generally speaking, it can ensure and improve various properties of the workpiece, such as wear resistance, corrosion resistance, etc. It can also improve the structure and stress state of the blank to facilitate various cold and hot processing. For example, after long-term annealing treatment of white cast iron, malleable cast iron can be obtained to improve plasticity; gears adopt the correct heat treatment process, and the service life can be doubled or dozens of times higher than that of gears without heat treatment; Some alloying elements have some expensive alloy steel properties and can replace some heat-resistant steels and stainless steels; almost all tools and dies need to be heat treated before they can be used.

Vacuum method

Because the heating and cooling of the metal workpiece requires dozens or even dozens of actions to complete. These actions are carried out in the vacuum heat treatment furnace, which cannot be approached by operators, so the requirements for the automation degree of the vacuum heat treatment furnace are relatively high. At the same time, some actions, such as after heating and heat preservation, the quenching process of metal workpieces requires six or seven actions and should be completed within 15 seconds. Such agile conditions to complete many actions, it is easy to cause operator tension and constitute misoperation. Therefore, only higher automation can accurately and timely coordinate according to the program. The vacuum heat treatment of metal parts is carried out in a closed vacuum furnace, and the strict vacuum sealing is well known. Therefore, obtaining and maintaining the original air leakage rate of the furnace and ensuring the working vacuum degree of the vacuum furnace are of great significance to ensuring the quality of the vacuum heat treatment of the parts. Therefore, a key problem of the vacuum heat treatment furnace is to have a reliable vacuum sealing structure. In order to ensure the vacuum performance of the vacuum furnace, a basic principle must be followed in the structural design of the vacuum heat treatment furnace, that is, the furnace body should be welded with airtightness, and at the same time, the furnace body should be opened as little or no holes as possible, and dynamic seals should be used less or avoided. structure to minimize the chance of vacuum leaks. The components and accessories installed on the vacuum furnace body, such as water-cooled electrodes and thermocouple lead-out devices, must also be designed with a sealed structure. Most heating and insulating materials can only be used in a vacuum. The heating and insulating linings of the vacuum heat treatment furnace work under vacuum and high temperature, so these materials are required to be resistant to high temperature, good radiation performance, and small thermal conductivity. Antioxidative properties are not required. Therefore, the vacuum heat treatment furnace widely uses tantalum, tungsten, molybdenum and graphite as heating and heat insulation materials. These materials are easily oxidized in the atmospheric state, therefore, these heating and insulating materials cannot be used in ordinary heat treatment furnaces. Water-cooling device: The furnace shell, furnace cover, electric heating element, water-cooled electrode, intermediate vacuum insulation door and other components of the vacuum heat treatment furnace all work in a vacuum and heated state. Working under such extremely unfavorable conditions, it is necessary to ensure that the structure of each component is not deformed or damaged, and that the vacuum sealing ring is not overheated or burned. Therefore, each component should be equipped with a water cooling device according to different conditions to ensure that the vacuum heat treatment furnace can operate normally and have sufficient service life. Using low voltage and high current: In the vacuum container, when the vacuum space is within the range of several Torr to lxlo-1 Torr, the energized conductor in the vacuum container will produce glow discharge at a higher voltage. In the vacuum heat treatment furnace, severe arc discharge will burn down the electric heating element, heat insulation layer, etc., resulting in major accidents and losses. Therefore, the working voltage of the electric heating element of the vacuum heat treatment furnace generally does not exceed 80-100 volts. At the same time, effective measures should be taken in the structural design of the electric heating element, such as avoiding sharp-edged parts as much as possible, and the distance between the electrodes should not be too small to prevent the generation of glow discharge or arc discharge.

Sub craft

Annealing Heat Treatment Sulfurization Heat Treatment Hardening Heat Treatment for Stress Relief Heat Treatment

Surface quenching

Case hardening and tempering heat treatment is usually carried out by induction heating or flame heating. The main technical parameters are surface hardness, local hardness and effective hardened layer depth. Vickers hardness tester can be used for hardness testing, Rockwell or surface Rockwell hardness tester can also be used. The selection of the test force (scale) is related to the depth of the effective hardened layer and the surface hardness of the workpiece. There are three durometers involved here. 1. Vickers hardness tester is an important method to test the surface hardness of heat-treated workpieces. It can use a test force of 0.5-100kg to test the surface hardened layer as thin as 0.05mm thick. Its accuracy is yes, and it can distinguish the surface hardness of heat-treated workpieces. small differences. In addition, the depth of the effective hardened layer is also detected by a Vickers hardness tester. Therefore, it is necessary to have a Vickers hardness tester for units that perform surface heat treatment processing or use a large number of surface heat treatment workpieces. 2. The surface Rockwell hardness tester is also very suitable for testing the hardness of surface quenched workpieces. There are three scales for the surface Rockwell hardness tester to choose from. Various case-hardened workpieces with an effective hardening depth of more than 0.1mm can be tested. Although the accuracy of the surface Rockwell hardness tester is not as high as that of the Vickers hardness tester, it has been able to meet the requirements as a detection method for quality management and qualification inspection of heat treatment plants. Moreover, it also has the characteristics of simple operation, convenient use, low price, rapid measurement, and direct reading of hardness values. Using the surface Rockwell hardness tester, batches of surface heat-treated workpieces can be quickly and non-destructively tested piece by piece. This has important implications for metalworking and machine building plants. 3. When the surface heat treatment hardening layer is thick, the Rockwell hardness tester can also be used. When the thickness of the heat treatment hardened layer is 0.4-0.8mm, the HRA scale can be used, and when the thickness of the hardened layer exceeds 0.8mm, the HRC scale can be used. The three hardness values of Vickers, Rockwell and superficial Rockwell can be easily converted to each other and converted into standard, drawing or user-required hardness value. The corresponding conversion table has been given in the international standard ISO, American standard ASTM and Chinese standard GB/T.

Local quenching

If the local hardness of the parts is high, the local quenching heat treatment can be carried out by means of induction heating. For such parts, the location of the local quenching heat treatment and the local hardness value are usually marked on the drawings. The hardness test of the parts should be carried out in the designated area. The hardness testing instrument can use the Rockwell hardness tester to test the HRC hardness value. If the heat treatment hardened layer is shallow, the surface Rockwell hardness tester can be used to test the HRN hardness value.
Chemical heat treatment is to make the surface of the workpiece infiltrate the atoms of one or several chemical elements, thereby changing the chemical composition, structure and properties of the surface of the workpiece. After quenching and low temperature tempering, the surface of the workpiece has high hardness, wear resistance and contact fatigue strength, and the core of the workpiece has high strength and toughness

Frequently encountered problems

Overheating: Overheating of the microstructure after quenching can be observed from the rough mouth of the bearing part. But to accurately judge the degree of its overheating must observe the microstructure. If coarse acicular martensite appears in the quenched structure of GCr15 steel, it is a quenched superheated structure. The reason for the formation may be the overall overheating caused by the quenching heating temperature is too high or the heating and holding time is too long; it may also be due to serious banded carbides in the original structure, forming local martensitic needle-like thick in the low-carbon area between the two bands, localized overheating. The retained austenite in the superheated structure increases and the dimensional stability decreases. Due to the overheating of the quenched structure and the coarse crystals of the steel, the toughness of the parts will be reduced, the impact resistance will be reduced, and the life of the bearing will also be reduced. Severe overheating can even cause quenching cracks.

Underheating: if the quenching temperature is too low or the cooling is poor, a tortenite structure exceeding the standard will be produced in the microstructure, which is called underheating structure, which reduces the hardness and wear resistance sharply, which affects the bearing life of idler parts .

Quenching cracks: The high temperature cooling is too rapid, the thermal stress and the structural stress of the metal mass volume change are greater than the fracture strength of the steel; the original defects of the working surface (such as surface microcracks or scratches) or the internal defects of the steel (such as slag inclusions) , serious non-metallic inclusions, white spots, shrinkage cavity residues, etc.) form stress concentration during quenching; severe surface decarburization and carbide segregation; parts are insufficiently tempered or not tempered in time after quenching; cold caused by previous processes Excessive punching stress, forging folding, deep turning tool marks, sharp edges and corners of oil grooves, etc. In short, the cause of quenching cracks may be one or more of the above factors, and the existence of internal stress is the main reason for the formation of quenching cracks. The quenching crack is deep and slender, the fracture is straight, and the fracture surface has no oxidation color. It is often a longitudinal straight crack or annular crack on the bearing ring; the shape on the bearing steel ball is S-shaped, T-shaped or annular. The organizational characteristics of quenching cracks are that there is no decarburization on both sides of the cracks, which is obviously different from forging cracks and material cracks.

Heat treatment deformation: During heat treatment of bearing parts, there are thermal stress and tissue stress. This internal stress can be superimposed or partially offset, which is complex and changeable, because it can vary with heating temperature, heating speed, cooling method, cooling speed. , The shape and size of the parts change, so heat treatment deformation is inevitable. Knowing and mastering its changing law can make the deformation of bearing parts (such as the ellipse of the ferrule, the size increase, etc.) in a controllable range, which is beneficial to the production. Of course, the mechanical impact during the heat treatment will also deform the part, but this deformation can be reduced and avoided with improved operations.

Surface decarburization: During the heat treatment process of bearing parts, if they are heated in an oxidizing medium, the surface will be oxidized to reduce the mass fraction of carbon on the surface of the parts, resulting in surface decarburization. The depth of the surface decarburization layer exceeds the allowance of final machining and the part is scrapped. Determination of the depth of the surface decarburization layer can be used in metallographic examination metallographic method and microhardness method. The measurement method of the microhardness distribution curve of the surface layer shall prevail, which can be used as the arbitration criterion.

Soft spot: The phenomenon of insufficient local hardness on the surface of roller bearing parts caused by insufficient heating, poor cooling, and improper quenching operation is called quenching soft spot. Like surface decarburization, it can cause a serious decrease in surface wear resistance and fatigue strength.

Commonly Used Standard

AD 2000-MERKBLATT HP 7/1 – Heat treatment – General principles
AD 2000-MERKBLATT HP 7/2 – Heat treatment – Ferritic steels
AD 2000-MERKBLATT HP 7/3 – Heat treatment – Austenitic steels
AD 2000-MERKBLATT HP 7/4 – Heat treatment – Aluminium and aluminium alloys
AENOR UNE-EN ISO 4885 – Ferrous materials – Heat treatments – Vocabulary (ISO 4885:2018)
AENOR UNE-EN ISO 4885 ENG – Ferrous materials – Heat treatments – Vocabulary (ISO 4885:2018)
AGMA 10FTM04 – Low Distortion Heat Treatment of Transmission Components
AGMA 12FTM21 – Typical Heat Treatment Defects of Gears and Solutions Using FEA Modeling
AGMA 12FTM23 – Enhancing Control of Distortion Through ‘One Piece Flow – Heat Treatment’
AGMA 13FTM22 – Heat Treatment of Large Components
API STD 20H – Heat Treatment Services—Batch Type for Equipment Used in the Petroleum and Natural Gas Industry
API STD 20N – Heat Treatment Services—Continuous Line for Equipment Used in the Petroleum and Natural Gas Industry
ASD-STAN PREN 4268 – Aerospace series Metallic materials Heat treatment facilities General requirements
ASME B31P – Standard Heat Treatments for Fabrication Processes
ASTM B661 – Standard Practice for Heat Treatment of Magnesium Alloys
ASTM B661-12 – Standard Practice for Heat Treatment of Magnesium Alloys
ASTM B661-12(2020) – Standard Practice for Heat Treatment of Magnesium Alloys
ASTM B807/B807M – Standard Practice for Extrusion Press Solution Heat Treatment for Aluminum Alloys
ASTM B807/B807M-20 – Standard Practice for Extrusion Press Solution Heat Treatment for Aluminum Alloys
ASTM B917/B917M-12(2020) – Standard Practice for Heat Treatment of Aluminum-Alloy Castings From All Processes
ASTM B918/B918M – Standard Practice for Heat Treatment of Wrought Aluminum Alloys
ASTM B918/B918M-17a – Standard Practice for Heat Treatment of Wrought Aluminum Alloys
ASTM B918/B918M-20a – Standard Practice for Heat Treatment of Wrought Aluminum Alloys
ASTM B947 – Standard Practice for Hot Rolling Mill Solution Heat Treatment for Aluminum Alloy Plate
ASTM B947-14 – Standard Practice for Hot Rolling Mill Solution Heat Treatment for Aluminum Alloy Plate
ASTM B947-14(2020)e1 – Standard Practice for Hot Rolling Mill Solution Heat Treatment for Aluminum Alloy Plate
BS EN 3481 – Aerospace series – Steel X8CrNiTi18-10 (1.4878/1.4544) – Annealed – Reference heat treatment: softened – Hollow bars – 5 mm ≤ a ≤ 12 mm
BS EN 3482 – Aerospace series – Steel X8CrNiTi18-10 (1.4878/1.4544) – Annealed – Reference heat treatment: softened – Forging stock – De ≤ 100 mm
BS EN 3484 – Aerospace series — Steel X5CrNiCuNb16-4 (1.4549 type 1.4542) — As cast — Reference heat treatment: homogenised, solution treated, precipitation hardened and sub zero — Remelting stock
BS EN ISO 4885 – Ferrous materials — Heat treatments — Vocabulary
BS PD CEN ISO/TR 14745 – Welding – Post-weld heat treatment parameters for steels
DIN EN 10263-2 – Steel rod, bars and wire for cold heading and cold extrusion – Part 2: Technical delivery conditions for steels not intended for heat treatment after cold working
DIN EN 3481 – Aerospace series – Steel X8CrNiTi18-10 (1.4878/1.4544) – Annealed – Reference heat treatment: softened – Hollow bars – 5 mm ≤ a ≤ 12 mm; German and English version EN 3481:2019
DIN EN 3482 – Aerospace series – Steel X8CrNiTi18-10 (1.4878/1.4544) – Annealed – Reference heat treatment: softened – Forging stock – De ≤ 100 mm; German and English version EN 3482:2019
DIN EN ISO 4885 – Ferrous materials – Heat treatments – Vocabulary (ISO 4885:2018)
DNVGL-CP-0351 – Manufacture of heat treated products – heat treatment workshop
DS/CEN ISO/TR 14745 – Welding – Post-weld heat treatment parameters for steels
DS/EN 10263-2 – Steel rod, bars and wire for cold heading and cold extrusion – Part 2: Technical delivery conditions for steels not intended for heat treatment after cold working
DS/EN 3481 – Aerospace series – Steel X8CrNiTi18-10 (1.4878/1.4544) – Annealed – Reference heat treatment: softened – Hollow bars – 5 mm ≤ a ≤ 12 mm
DS/EN 3482 – Aerospace series – Steel X8CrNiTi18-10 (1.4878/1.4544) – Annealed – Reference heat treatment: softened – Forging stock – De ≤ 100 mm
DS/EN 3484 – Aerospace series – Steel X5CrNiCuNb16-4 (1.4549 type 1.4542) – As cast – Reference heat treatment: homogenised, solution treated, precipitation hardened and sub zero – Remelting stock
DS/EN 4268 – Aerospace series – Metallic materials – Heat treatment facilities – General requirements
DS/EN ISO 4885 – Ferrous materials – Heat treatments – Vocabulary (ISO 4885:2018)
FORD WK902 – DIMENSIONS, MATERIAL, HEAT TREATMENT, AND PERFORMANCE OF SPRING BAND HOSECLAMPS
ISO 4885 – Ferrous Products – Heat Treatments – Vocabulary
ISO TR 14745 – Welding – Post-weld heat treatment parameters for steels
MIL-STD-1684 – CONTROL OF HEAT TREATMENT
SAE AMS2728 – Heat Treatment of Wrought Copper Beryllium Alloy Parts
SAE AMS2759 – Heat Treatment of Steel Parts General Requirements
SAE AMS2759/1 – Heat Treatment of Carbon and Low-Alloy Steel Parts Minimum Tensile Strength Below 220 ksi (1517 MPa)
SAE AMS2759/2 – Heat Treatment of Low-Alloy Steel Parts Minimum Tensile Strength 220 ksi (1517 MPa) and Higher
SAE AMS2759/3 – Heat Treatment Precipitation-Hardening Corrosion-Resistant, Maraging, and Secondary Hardening Steel Parts
SAE AMS2759/4 – (R) Heat Treatment Austenitic Corrosion-Resistant Steel Parts
SAE AMS2759/5 – Heat Treatment Martensitic Corrosion-Resistant Steel Parts
SAE AMS2759/6 – (R) Gas Nitriding of Low-Alloy Steel Parts
SAE AMS2759/7 – Carburizing and Heat Treatment of Carburizing Grade Steel Parts
SAE AMS2761 – Heat Treatment of Steel Raw Materials
SAE AMS2768 – Heat Treatment of Magnesium Alloy Castings
SAE AMS2769 – Heat Treatment of Parts in a Vacuum
SAE AMS2770 – Heat Treatment of Wrought Aluminum Alloy Parts
SAE AMS2771 – Heat Treatment of Aluminum Alloy Castings
SAE AMS2772 – Heat Treatment of Aluminum Alloy Raw Materials
SAE AMS2773 – Heat Treatment Cast Nickel Alloy and Cobalt Alloy Parts
SAE AMS2774 – Heat Treatment Nickel Alloy and Cobalt Alloy Parts
SAE AMS2801 – Heat Treatment of Titanium Alloy Parts
SAE AMS-H-6088 – Heat Treatment of Aluminum Alloys
SAE AMS-H-6875 – Heat Treatment of Steel Raw Materials
SAE AMS-H-81200 – Heat Treatment of Titanium and Titanium Alloys
SAE AMS-M-6857 – Magnesium Alloy Castings, Heat Treatment of magnesium alloy castings.
SAE ARP7500 – Minimization of High Temperature Oxidation, Aluminum Alloy Heat Treatment
SAE J437 – Selection and Heat Treatment of Tool and Die Steels
GB/T7232-2012 Metal Heat Treatment Process Terminology 2013-03-01 Implementation, instead of GB/T 7232-1999
GB/T8121-2002 Terms of Materials for Heat Treatment Processes Implemented on 2002-12-01, replacing GB/T 8121-1987
GB/T9452-2003 Determination method of effective heating zone of heat treatment furnace implemented on 2004-06-01, replacing GB/T 9452-1988
GB/T17031.1-1997 Dry heat effect of textile fabrics under low pressure – Part 1: Dry heat treatment procedures for fabrics Implemented on 1998-05-01
GB/T7631.14-1998 Classification of Lubricants and Related Products (Class L) Part 14: Group U (Heat Treatment) Implemented on 1999-02-01
GB/Z18718-2002 Technical Guidelines for Energy Conservation in Heat Treatment Implemented on 2002-12-01
GB15735-2004 Metal Heat Treatment Production Process Safety and Hygiene Requirements Implemented on 2004-11-01, replacing GB 15735-1995
GB/T12603-2005 Metal Heat Treatment Process Classification and Code 2006-01-01 Implementation, instead of GB/T 12603-1990
GB/T19944-2005 Fuel consumption quota for heat treatment production and its calculation and determination method Implemented on 2006-04-01
GB/T13324-2006 Terminology of heat treatment equipment implemented on 2007-04-01, replacing GB/T 13324-1991
GB/T21736-2008 Technical Conditions for Energy-Saving Heat Treatment Combustion Heating Equipment Implemented on 2008-11-01
GB/T10201-2008 Guidelines for Rational Use of Electricity for Heat Treatment 2009-01-01 Implementation, instead of GB/T 10201-1988
GB/T22561-2008 Vacuum heat treatment implemented on 2009-06-01
GB/T17358-2009 Calculation and Determination of Electricity Consumption in Heat Treatment Production Implemented on 2009-11-01
GB/T5953.2-2009 Cold heading steel wire Part 2: Non-heat-treated cold heading steel wire Implemented on 2010-04-01, replacing GB/T 5953-1999
GB/T5953.1-2009 Cold heading steel wire Part 1: Heat treatment type cold heading steel wire Implemented on 2010-04-01, replacing GB/T 5953-1999
GB/T24562-2009 Energy-saving Monitoring of Fuel Heat Treatment Furnaces Implemented on 2010-05-01
GB/T24743-2009 Technical Product Document Heat Treatment Representation of Steel Parts Implemented on 2010-09-01
GB/T15318-2010 Energy-saving monitoring of electric furnaces for heat treatment Implemented on 2011-02-01, replacing GB/T
GB/T25745-2010 Cast aluminum alloy heat treatment 2011-06-01 implementation
GB/T27946-2011 Limits of Hazardous Substances in the Air of Heat Treatment Workplaces
GB/T27945.1-2011 Management of Hazardous Solid Waste from Heat Treatment Salt Bath Part 1: General Management
GB/T27945.2-2011 Management of Hazardous Solid Waste from Heat Treatment Salt Bath Part 2: Leachate Detection Method
GB/T27945.3-2011 Management of Hazardous Solid Waste from Heat Treatment Salt Bath Part 3: Harmless Treatment Methods
GB/T7232-2012 Terms of Metal Heat Treatment Process Announcement No. 24 of 2012
GB/T8121-2012 Terms of Materials for Heat Treatment Processes Announcement No. 24 of 2012
GB/T9452-2012 Determination method of effective heating area of heat treatment furnace Announcement No. 24 of 2012
GB/T28909-2012 Announcement No. 28 of 2012 for Ultra-high Strength Structural Heat-treated Steel Plates
GB15735-2012 Safety and Hygiene Requirements for Metal Heat Treatment Production Process Announcement No. 28 of 2012
GB/T28838-2012 Specification for heat treatment of wood packaging Announcement No. 28 in 2012
GB/T28992-2012 Heat-treated solid wood flooring Announcement No. 41 of 2012
GB13014-1991 Reinforced concrete with residual heat treatment steel bars Implemented on 1992-03-01, replacing GB 1499-1984