Mar. 17, 2025
Stands for American Iron and Steel Institute. The institute serves as the voice of the North American steel industry. AISI numbers are used to categorize metals by alloy type and carbon content, and they do it with four digits. The first two digits of an AISI number refer to the alloy type, and the second two digits refer to carbon content.
A metal made by combining two or more metallic elements. An alloy typically possesses qualities different from those of the components used to create it.
Stands for American Society for Metals. ASM International is the world's largest association of metal material engineers and scientists. The association engages and connects materials professionals and their organizations to the resources necessary to solve problems, improve outcomes, and advance society.
Stands for American Society for Testing and Materials. ASTM International is a not-for-profit organization that develops standards for materials, products, systems, and services. Metal with an ASTM designation meets the international standards for quality and regulations.
This process levels coil into a flat sheet or blank. The service provides better length and width tolerances than sheared product, and it can improve diagonal tolerances as well.
Cutting metals can leave behind burrs, which are unwanted raised edges or protrusions. Deburring is the process of removing these burrs with a tool.
Drawing is a metalworking process that uses tensile forces to stretch metal. As the metal is drawn, it stretches thinner, into a desired shape and thickness.
Drawing is usually done at room temperature, classifying it as a cold working process. However, it may be performed at elevated temperatures during special applications like on large wires, rods, or hollow sections in order to reduce forces.
A metal fabricating term that refers to the degree to which a material can be bent, stretched, or compressed before rupturing. A metal's elongation is a point between tensile strength and yield strength, and it is typically expressed as a percentage of the original length.
The thickness of sheet metal in the USA is commonly specified by a traditional, non-linear measure known as its gauge. The larger the gauge number, the thinner the metal.
A heat number is an identification number that is stamped on a material plate to prove it meets industry quality standards which require materials to be tested by the manufacturer. The heat lot or heat number is used to identify production runs for quality control purposes.
Edge rolling is the process of adding finishing edges to metal. It forms the edge of a strip to the desired shape beyond that of a standard slit edge.
Stands for Military Standard. This classification establishes uniform engineering and technical requirements for military-unique or substantially modified commercial processes, procedures, practices, and methods. In order to qualify, materials have undergone rugged, exact testing, equal to the exigencies of combat use.
Normalization is a heat treatment that relieves stress on steel to improve ductility and toughness in steel that may harden after the cold working process. During normalization, steel is warmed to a temperature just above its upper critical point. Normalized heat treatment facilitates a more uniform final product.
The Rockwell Scale indicates the hardness of materials. Rockwell hardness numbers are most often used to describe the hardness of metals, although they are also used for some plastics. The Rockwell scale is based on measuring the depth of the indentation made by pressing a diamond point into a material.
Stands for Society of Automotive Engineers. SAE International is a global association of engineers and related technical experts in the aerospace, automotive, and commercial-vehicle industries. Materials meeting SAE standards are internationally recognized for safety, quality, and effectiveness.
Slitting is a precise shearing process, but instead of making cuts at the end of a workpiece like shearing, slitting cuts a wide coil of metal into a number of narrower coils as the main coil is moved through the slitter. During the slitting process, the metal coil passes lengthwise through the slitter's circular blades.
Temper refers to reheating hardened, normalized, or mechanically worked steel to a temperature below the critical range to soften it and improve impact strength. Tempering results in greater toughness by decreasing an alloy's hardness.
The maximum stress a material will withstand before fracturing or breaking. The ultimate tensile strength is calculated from the maximum load applied during the test, divided by the original cross-sectional area.
Stands for the Unified Numbering System for Metals and Alloys. UNS designation provides a means of correlating internationally used metal and alloy numbering systems currently administered by societies, trade associations, and those individual users and producers of metals and alloys. This system is meant to avoid the confusion caused by using more than one identification number for the same metal or alloy, and the opposite situation of having the same number assigned to two or more different metals or alloys.
The amount of stress a material can withstand before causing permanent deformity.
AISI Steel is a particular type of steel alloy assigned prefix code by the AISI system.This letter prefix is mainly used to denote the steelmaking process of the AISI Steel.
The grade number in the steel alloys makes sure to differentiate their industrial applications.
4: The first number '4' indicates that the steel is 'Molybdenum' steel and Molybdenum is most important alloy element for this steel as compared to other steel series.
3:The second number'3' means that three (3) elements are present, and they include nickel, chromium, and molybdenum.
40: The last two numbers '40' indicates the amount of carbon present in the steel. For this grade it has 0.40% carbon same as AISI steel.
Moreover, this particular number is assigned to almost all the steel alloys by AISI to designate the different steel compositions in its alloys.
AISI Steel is supplied in round, square, flat, block, and shaft forms from China to other countries.Besides all the forms mentioned above, some other supply forms of AISI steel include the plain sheets and hexagonal bars.
The properties and the composition of the AISI steel remain the same regardless of their shape.In addition to this, the sturdy nature of AISI Steel has made it importable in the form of hardened and tempered conditions.
You have to keep in mind to provide options to the manufacturer while ordering them to supply AISI steel.
AISI Forged Round Steel with Quenched and Tempered Conditon-Dia 780mm
With the development of global trade, global procurement, manufacturing and engineering, the demand for steel grades from different countries has become more and more urgent.
But each country has different material standards and grades.For example, the European Union, the United States, Japan, and China have their own steel standards and grade systems.They design and substitute materials according to their actual situation,that's why there is a demand for alternative steel grades.
AISI Steel, popular American grade steel, which is made of high-quality carbon structural steel by appropriately adding one or several alloying elements (Cr-Ni-Mo with a total content of not more than 5%).We can see the differences between different national standards from the table below.
StandardGradeCSiMnPSCrNiMo ASTM A.38-0.430.15-0.350.6-0.8' 0.035' 0.040.7-0.91.65-2.00.2-0.3AISI alloy structural steel belongs to gear steel which has high strength, toughness and outstanding hardenability and anti-thermal stability.
AISI Steel is used for heavy machinery high-load shafts, turbine shafts with a diameter greater than 250 mm, helicopter rotor shafts, turbojet engine turbine shafts, blades, high-load transmission parts, crankshafts,gears,etc.
But before we use them for above applications,we need to harden the materials according to requirements.In the actual production process,we often use water quench and oil quench to harden AISI Steel.
Water QuenchOil Quench Quench MediumWaterOil Quench Temperature850~870'850~870' Quench TimeNormalLonger Cooling abilityBetterNormal Crack ResistancePoorNormal DeformationBiggerNormal HardnessHigherNormal HardenabilityBetterNormal Tempering FollowingImmediatelyImmediatelyWhen we use AISI steel for applications,we choose its high strength,high hardness and excellent toughness.Normally,AISI steel has a hardness below 229 HBW under annnealed conditon,248-302HBW under quenched and tempered condition.With suitable hardening process,it can even achieve surface hardness up to 60HRC.
But can it be considered that the higher the hardness, the better the performance?Of course not.
The higher the hardness, the greater the strength, but the plasticity and toughness decrease. Especially in the case of quenching and tempering conditon, in order to ensure the strength, it is necessary to find a balance point between the strength and the toughness.
AISI Steel Chart:Tempering temperature VS Tensile VS Enlogation VS Reduction of Area & Impact
As a very popoluar grade,AISI Steel has good forging performance,but with Cr-Ni-Mo alloy elements,it must be paid more attention when forging.Here are some important key points need to be concerned.
Initial forging temperature for AISI Steel must be controled between -' when heating in the furnace.Once higher than this temperature,it may cause overheated structure and decarburization.But the initial forging temperature should not be too low, otherwise it will shorten the forging operation time, narrow the forging temperature range, and increase the difficulty of forging.
Final forging temperature for AISI Steel,in our experience should be operated above 850'.Generally speaking, the final forging temperature should be as low as possible, which can extend the forging time and reduce the number of heating. However, if the temperature is too low, the plasticity of the material decreases, the deformation resistance increases, and the forgeability also deteriorates. The material will also be work hardened and even cracked. If the final forging temperature is too high (that is, stop forging at high temperatures), the forgings will have coarser grains and lower mechanical properties.
If you are looking for more details, kindly visit Youngson.
AISI Steel Shaft Forging By T Forging Press
As the forging ratio increases during the forging process, the internal pores are compressed, the casting grain structure will be broken, and the longitudinal and transverse mechanical properties of the forging material are significantly improved. If the forging section ratio is too small, the forging will not meet the performance requirements, and also cause th internal structure loose,but if it is too large, it will increase the forging workload and cause anisotropy.According to our experience,for AISI Steel bars,we usually control the forging ratio with Upsetting and Drawing Process,and guarantee it above 4:1
Upsetting & Drawing Process Diagram
AISI Steel is an alloy structural steel with high hardenability which contains Cr-Ni-Mo alloy elements.Uneven cooling or local rapid cooling will cause great internal stress,and may easily causes surface cracks.It is recommended that it should be buried sand cooling or furnace cooling after forged.
In our experience,the best way to cooling steel is annealing.The main purpose is to prevent white spots and hydrogen embrittlement, eliminate internal stress, reduce hardness, improve the cutting performance of forgings, improve the internal structure of the parts, refine the grains, and prepare for the final heat treatment.
With the increase of the heating temperature in the tempering process,the hardness and strength of the steel decrease, while the ductility and toughness increase, but the impact value is significantly reduced to the lowest value when tempered within a certain temperature range. This phenomenon is called tempering brittleness.
Similarly, AISI steel also has this tempering brittleness feature .Research shows that there is a big loss in toughness(especially for Charpy V-notch impact)after tempering at around 300°C due to retained interlath austenite and the formation of interlath carbide films.
Fracture analysis shows that for all of the tempering temperatures, the fracture features are predominated by the ductile mode with a dimple structure, except for the case of 300°C,where the material failed in a brittle manner due to the occurrence of tempered martensite embrittlement.
From the above, we can know that,We should avoid tempering AISI steel at around 300 degrees with long time.
Relation Chart:AISI Steel Tempering Temperature VS Area Reduction & Elongation
Is AISI Stainless Steel?
Stainless steel has at least 10.5% Chromium, and the maximum carbon content is not more than 1.2%.The main characteristics for these kind materials are good rust resistance and corrosion resistance.
While AISI is defined as a heat-treatable low-alloy steel containing 0.8% Cr, 0.2% Mo and 1.8% Ni as strengthening alloying elements.Compared with Stainless steel,it has higher strength and toughness, but its wear resistance and atmospheric corrosion resistance are not as good as stainless steel.
Is AISI Steel Corrosion Resistant?
AISI steel is a medium-carbon nickel-chromium-molybdenum steel which has excellent tensile strength, toughness and fatigue resistance.
AISI Steel is highly resistant to atmospheric corrosion because of its combined alloy elements of chromium, molybdenum,nickel and manganese which can not only improve the strength and hardenability of steel, but also improve corrosion resistance.
The corrosion-resistant nature of the AISI Steel is responsible for its use in the forged hydraulic systems,and it is also used in many other machine appliances, including those involved in the aerospace industry.
Is AISI Steel Magnetic?
AISI Steel is manufactured with many basic properties, including high magnetic properties.Other than magnetic properties, the AISI Steel is also equipped with durable mechanical properties.
This steel allows very substantial magnetic properties because a few percent of alloying elements are present.The magnetization of the AISI steel is estimated at up to Gauss.
Can You Machine AISI Steel?
Yes, you can machine AISI Steel with the help of almost all types of conventional techniques.No excess carbon contents are present, that's why AISI steel can be machined easily.
This grade is easy to process, depending on the size and complexity of the section and the amount of processing to be carried out.The machining of AISI steel is carried out under an assumed shape.
However, the recommended machining process for AISI Steel is carried out under annealed,normalized and tempered environments.
How is The Weldability of AISI Steel?
AISI Steel is recommended to weld in the annealed condition, but welding in the quenched and tempered state should be avoided as much as possible, because this will affect the mechanical properties. It is not recommended to weld under nitriding, flame or induction hardening conditions.
In addition to this, the weldability of the AISI steel is carried out by preheating the material at 200 to 300 degrees.This high temperature for the welding is maintained to ensuring the sustainability of the substrate.The welded parts should be cooled slowly in the ashes or sand, and the stress should be relieved as much as possible.
M steel which is modified from AISI Steel,also known as 300M, is the steel grade in the American AMS standard.It is a low-alloy ultra-high-strength steel,the addition of vanadium and higher silicon content is added to produce higher strength levels.
Chemical Composition Comparison
M StandardAWS ASTM A29 C0.38-0.430.38-0.43 Si1.45-1.800.15-0.35 Mn0.6-0.90.6-0.8 P' 0.01' 0.035 S' 0.01' 0.04 Cr0.7-0.950.7-0.9 Ni1.65-2.0 1.65-2.0 Mo0.3-0.5Mechanical Performance Characteristics
After oil quenching and tempering with standard heat treatment, the tensile strength of M steel can reach above MPa, which is the highest strength low-alloy ultra-high-strength steel among the currently used materials.
High strength can reduce the weight of parts, and improving strength has always been one of the main goals pursued in the design of landing gear parts.The important load-bearing components of American aircraft wings have also adopted M steel and used it to the highest level of strength.
In the material standard, the transverse section shrinkage rate as the main mechanical performance index is the characteristic of M steel.This is based on the characteristics of the use of landing gear parts.
High fracture toughness indicates strong resistance to crack growth. When selecting materials, attention should be paid to both sharp notch toughness and blunt notch toughness. They represent different physical meanings, so they cannot replace each other.
The fatigue resistance of M steel is obviously excellent. This is extremely beneficial to the long-life use of landing gear and other aircraft components, and is also the main reason why M steel is widely used in aircraft.
1.5% silicon in the composition improves the stress corrosion resistance of M steel. Compared with similar steels, its stress corrosion resistance is better.
When you need AISI steel, but you can't find a suitable supplier from so many manufacturers.Try us
We can be your best pick for AISI Steel since it makes sure that every aspect meets customer's demands.
What We Supply For AISI Steel
Supply FormSize(mm)ProcessToleranceWhat Heat Treatment We Supply For AISI Steel
What Size We stock For AISI Steel
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