The Ultimate Buyer's Guide for Purchasing High-Performance Alloy Tool Steel

Author: Dorinda

May. 05, 2025

The Complete Guide to Buying Metal Products - Mead Metals

AISI

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.

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ALLOY

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.

ASM

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.

ASTM

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.

CUT-TO-LENGTH

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.

DEBURRING

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

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 TEMPERATURE

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.

ELONGATION

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.

GAUGE

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.

HEAT LOTS OR HEAT NUMBER

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

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.

MIL STD

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.

NORMALIZING TEMPERATURE

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.

ROCKWELL SCALE

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.

SAE

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

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

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.

TENSILE STRENGTH

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.

UNS DESIGNATION/NUMBER

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.

YIELD STRENGTH

The amount of stress a material can withstand before causing permanent deformity.

How to Buy AISI Steel?

WHAT IS AISI STEEL GRADE DESIGNATION?

To understand the AISI steel properties, it is important to understand what the grade numbers in it mean. Following is the AISI steel grade designation:

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. For example the steel series

1XXX: Carbon steel

5XXX: Chromium steel

1:  The second number ‘1’ indicates that this steel has Chromium element as the secondary alloy.For example the steel series as below

40XX: Mo 0.20-0.25%

44XX: Mo 0.40-0.52%

41XX: Cr 0.50-0.95%, Mo 0.12-0.30%

40:  The last two numbers ‘40’ indicates the amount of carbon present in the steel. For this grade it has 0.40% carbon compared with AISI steel which has 0.30% carbon.

WHAT ARE EQUIVALENT GRADES FOR AISI STEEL?

We can see the international equivalent grades as below.Compared with AISI Steel,each country adjust chemical composition to meet their actual requirement.It is also a good way to replace the material with similar grade.

StandardGradeCSiMnPSCrNiMo ASTM A.38-0.430.15-0.350.75-1.00≤ 0.035≤ 0.040.8-1.1–0.15-0.25
EN
42CrMo4
0.38-0.45
≤ 0.4
0.6-0.90
≤ 0.025
≤ 0.035
0.9-1.2

0.15-0.30 1. JIS GSCM.38-0.430.15-0.350.6-0.85≤ 0.035≤ 0.040.9-1.2–0.15-0.30 GB CrMo0.38-0.450.17-0.370.5-0.80≤ 0.035≤ 0..9-1.2–0.15-0.25 BS 970EN190.35-0.450.15-0.350.5-0.80≤ 0.035≤ 0..9-1.5–0.2-0.40

For Further Disscussion:

CAN WE USE AISI STEEL  INSTEAD OF 42CrMo4 STEEL?

42CrMo4 is European grade from EN standard,while AISI is American grade from ASTM A29 standard,they are internatioal eqnivalent grade,and have similar chemical chemical compositon.So we can adjust the amount of  alloy element in below table when we prodcue them.

Chemical Composition Adjustment for and 42CrMo4

CrMo4Adjustment for and 42CrMo4 C:0.38-0.43% C:0.38-0.45% C:0.38-0.43% Si:0.15-0.35% Si:≤ 0.4%Si:0.15-0.35% Mn:0.75-1.0% Mn:0.6-0.9%Mn:0.75-0.9% Cr:0.8-1.1% Cr:0.9-1.2%Cr:0.9-1.1% Mo:0.15-0.25% Mo:0.15-0.30%Mo:0.15-0.25%

42CrMo4 Steel Round Bar

WHAT IS THE DIFFERENCE BETWEEN AISI STEEL AND AISI STEEL?

From the AISI designation rules,First we know that has 0.4% percent carbon(0.38-0.43%) compared with which has lower o.3% carbon(0.28-0.33%).And also the Manganese is totally different,0.75-1.0% from compared with 0.4-0.6% from .But with same amount of Molybdenum and Chromium added to AISI steel and AISI steel,they become corrosion-resistant.The properties of molybdenum are especially important in this regard as it tries to resist corrosion that occurs due to chlorides. Manganese is also added to steel to improve its characteristics as a deoxidizer and also enhances its hardenability.Both of them are popular grade,widely used in oil and gad industry.

The steel is similar to steel but we can’t use them to replace.The steel has higher steel content as compared to steel. The steel also has greater strength and hardenability than steel. The welding ability of steel is better than but its wear-resistance performance is lower.Customers should consider what kind of performance you demand.

IS AISI STEEL HEAT TREATABLE?

Yes,As an alloy engineering steel,AISI steel is quite suitbale for heat treatment,The purposes for steel  heat treatment is to improve the mechanical properties of materials, relieve residual stress and improve the machinability.

According to the different purposes of heat treatment for AISI steel, the treatment process can be divided into Normalizing,Annealing,and Quenching & Tempering.

Which Condition Should Be Normalized For AISI Steel?

The normalizing of steel is a method by which a steel is heated above the temperature of the ferrite to austenite the range of transformation and then it is air cooled below the transformation range temperature.

As a conditioning treatment,the purpose of the preliminary heat treatment is to improve the processing performance, eliminate internal stress and prepare a good metallographic structure for the final heat treatment.

After hot working operation,AISI steel is generally normalized to get fine grain and make carbide distribution uniform before final heat treatment.For important forgings with complex shapes, high temperature tempering (550-650°C) is required after normalizing. The purpose of high temperature tempering is to eliminate the stress generated during normalizing cooling and improve toughness and plasticity.

For common structural parts that are not stressed and have low performance requirements made by AISI steel,compared with Annealing treatment,the normalized workpiece will have better comprehensive mechanical properties.Normalizing can be used as the final heat treatment to reduce the number of processes, Save energy and improve production efficiency.

AISI Steel Round Bar Normalizing

What Is Differences Between Normalizing And Annealing For AISI Steel?

Normalizing and Annealing heat treatment process is quite commonly used in production for AISI Steel.When we talk about them,we need to know their technical principle and  differences,and how to choose them when we face different requirements.

  • Temperature

The Normalizing temperature for AISI Steel is 850-860℃,while for Annealing temperature is around 800℃,which is lower than normalizing.

  • Holding Time

For the time keeping in the furnace,it depends on the thickness of the product made by steel,we should guarantee suitabe time for the material to be thoroughly heated.But it also needs to be pointed out that too much time will cause coarse grains.

Contact us to discuss your requirements of High-Performance Alloy Tool Steel. Our experienced sales team can help you identify the options that best suit your needs.

  • Cooling Speed Rate

The cooling rate of normalizing is faster than that of annealing.After finishing holding time,for normalizing,the material will be take out of the furnace,and cooling by spraying water, spraying or blowing in the air.While the mateial for will be Slowly cooled down with furnace temperature in the furnace.

  • Surface Hardness

As the difference on the cooling rate,normalized steel has higher hardness than of annealed.in our experience,In addition to hardness, the normalized structure is finer than the annealed structure, and its mechanical properties are also improved.

  • Heat Treatment Cycle

The normalizing cycle is short and the operation is convenient,and will not use furnace when cooling ; the annealing cycle is long and the operation is more troublesome, which means that a certain cooling rate needs to be controlled in the furnace.Normalizing is used as much as possible to replace annealing in production for high productivity

QUICK QUESTIONS FOR AISI STEEL

Is AISI Steel Low Alloy Steel?

Relatively to carbon steel,low alloy steel is based on carbon steel,and one or more alloying elements are intentionally added to the steel to improve the properties of steel, such as strength, hardness, toughness, wear resistance, and corrosion resistanc etc.the total amount of alloying elements less than 5%,called low alloy steel.

It is no doubt that AISI steel is a low-alloy steel that contains chromium, molybdenum and manganese alloy elements.Due to its excellent toughness, wear resistance, impact resistance and high fatigue strength, it is widely used in many industries.

Is AISI Steel Corrosion Resistant?

AISI Steel  is also regarded as “chromium-molybdenum alloy steel” mainly because it contains chromium and molybdenum.

Chromium, molybdenum and manganese can not only improve the strength and hardenability of steel, but also improve corrosion resistance, especially molybdenum can resist corrosion caused by chloride.

But it should be noted that once AISI steel is corroded, it will rust like most steel that suffers the same damage. The only advantage is that it has a certain degree of protection.

Is AISI Steel Machinable?

The AISI steel bar is available readily machinable especially in annealed condition. The complex shapes will require annealing but simple shapes can be machined smoothly along with a normalizing treatment. For optimum machinability, the steel grade’s carbon level might need a structure of coarse lamellar pearlite to coarse spheroidite.

How Is AISI Steel Weldability?

To weld the AISI steel, all the common arc welding processes can be used such as SAW, FCAW, SMAW, GTAW, and GMAW. Welding should always be done using low hydrogen electrodes. Welding of steel is not recommended in tempered condition (the condition in which it is normally supplied). If AISI steel is welded in the tempered condition, it will lose its mechanical properties in the weld heat affected zone.

Welding is carried out on the AISI steel when it is in annealed condition. The annealed steel is placed immediately for cooling to hand warm level, and then it is stress relieved at 595 to 620 degrees Celsius before hardening and tempering. If the work piece is in tempered condition and welding is very necessary, the piece should be stress relieved at 15 degrees Celsius below the original tempering temperature. AISI steel can be welded using any commercial method as it has good weldability.

AISI Steel vs AISI Steel

The type of steel comes from the same family( Chromium-Molybdenum Series) of the AISI steel. The very small difference is their percentage of carbon content.AISI has carbon content with 0.43-0.48%,0.05% higher than AISI Steel.Due to the slight difference in carbon content, the strength of steel is slightly higher than that of steel.

With suitable heat treatment, AISI and AISI steel have good comprehensive performance,and are widely used in the oil and gas industry.

AISI Forged Round Steel Bar

HOW IS THE CLEANLINESS FOR AISI STEEL?

Generally speaking, the purity of steel mainly refers to the information related to the number, type, morphology, size and distribution of non-metallic inclusions.

For AISI Steel, we ofen use ASTM-E45 standard to test its purity.Non-Inclusions are divided into 4 types, namely, type A (sulfide type), type B (alumina type), type C (silicate type) and type D (spherical or point oxide type).For each type,it is further divided to two series of fine series and coarse series according to their thickness or diameter.

We control the purity in accordance with the production process and execute in accordance with the following standards.

Non-metallic Inclusions ABCD FineCoarseFineCoarseFineCoarseFineCoarse Max 2.0Max 1.5Max 2.0Max 1.5Max 2.0Max 1.5Max 2.0Max 1.5

IS AISI STEEL SUITABLE FOR INDUCTION HARDENING?

Yes,AISI Steel can be applied with induction hardening with frequency -HZ(Medium Frequency),and High Frequency 200KHZ to 300KHZ.Due to the different frequency of the current, the input depth of the induced current is different during heating.When using high frequency, The depth of hardened layer is 1.0~2.0 mm,but while using medium frequency, The depth of hardened layer can be achieved to 2mm to 10mm.

For Medium Frequency Induction hardening,AISI steel is usually placed in an induction coil, and the induction coil is energized to generate an alternating electromagnetic field, which induces an alternating current in the metal parts.Due to the skin effect, the current is mainly concentrated on the surface of the metal part, so the surface temperature can be rised rapidly. The water spray cooling or other cooling is followed immediately under the induction coil to quench the material.

Advantages for AISI Steel Induction Hardening

  • Fast Heating Speed

With induction heating,the heating source is generated on the surface of the material,it makes the temperature rise quickly with high thermal efficiency

  • Small Deformation

Compared with Normal Hardening in the furance,the material is not heated as a whole,and the core part is not thoroughly heated,so the deformation is small.

  • Little Surface oxidation & Small Decarburization

Compared with Normal heating in the furance,the heating time is extremely small.The workpiece processed by this process is not easy to be oxidized and decarburized, and even some workpieces can be directly assembled and used after processing.

  • Good Performance

While get high surface hardness,the notch sensitivity is small, and the impact toughness, fatigue strength and wear resistance are greatly improved after hardening. Conducive to exert the potential of materials, save material consumption, and increase the service life of parts.

  • High productivity

This hardening method is suitable for mass production, easy to control and operate,and easy to realize mechanization and automation.

WHAT ARE ADVANTAGES FOR AISI COLD DRAWN STEEL?

  • High Accuracy

According to the design plan, cold-drawn steel has different shapes of abrasive tools, and cold-drawn different cross-sectional shapes, different specifications, and size tolerances. The angle of view can be designed as an oblique angle or arc.AISI Cold-drawn steel uses high-quality cemented carbide molds  to to ensure precise and uniform dimensional tolerances.

  • Surface Smooth

The surface of AISI steel becomes bright and smooth after cold drawing,and the surface layer is steadily growing. It can be applied immediately, such as painting, sanding, bending, punching, or electroplating process immediately after fine drawing according to specific regulations, eliminating a lot of machining time and saving cost on equipment processing.

Dia 5/8 inch(15.88mm) Round steel for AISI

  • Save Raw Material

The cold drawing process is to transform the raw materials to the required shape, specifications and dimensional tolerances by hot forging. The loss of raw materials is very small.Relatively, using traditional CNC lathes to process the raw materials lost in drilling,and cutting materials, the saving of raw materials is obvious,especially when the amount of raw materials used is large, more raw materials will be  saved considerably.

WHAT IS API 6A 60K AND 75K FOR AISI STEEL IN OIL AND GAS INDUSTRY?

API 6A  and 16A specify four standard material property designations, 36K 45K 60K and 75K which are defined by their yield strength. 60K and 75K are most widely used in bodies,bonnets and end and outlet connections in oil and gas industry.The following table lists the API Spec 6A material designations and the measured minimum mechanical property requirements include:

  • Tensile strength
  • Yield strength
  • Hardness
  • Impact strength
  • A minium of 15% elongation
  • A minium of 20% reduction of area
Material Designation0.2% Offset yield strength
Min,Mpa(psi)Tensile strength
Min,Mpa(psi)Elongation in 50 mm (2 in)
Min,%Reduction in Area
Min,% 36K248(36,000)483(70,000)21No requirement 45K310(45,000)483(70,000) 60K414(60,000)586(85,000) 75K517(75,000)655(95,000)

Hardness requirement for typical material grade

MaterialAPI Min.Yield/Min.HBWNACE Max.HBW A105 Carbon Steel36K/ Carbon Steel60K/ Low Alloy Steel60K/174,75K/ Low Alloy Steel60K/174,75K/ Low Alloy Steel60K/174,75K/ 410 Stainless Steel60K/174,75K/

Charpy-V impact requirement(10mm x 10mm)



Temperature

Minimum Average Impact Value,J( ft-lb) Transverse DirectionLongitudinal Direction Wrought or Cast Material,Weld QualificationAlternate Method for Wrought Products Only ClassTest °C(°F)PSL1 and PSL2PSL3 and PSL4PSL1 and PSL2PSL3 and PSL4 K-60(-75)20(15)20(15)27(20)27(20) L-46(-50)20(15)20(15)27(20)27(20) N-46(-50)20(15)20(15)27(20)27(20) P-29(-20)20(15)20(15)27(20)27(20) S-18(0)-20(15)-27(20) T-18(0)-20(15)-27(20) U-18(0)-20(15)-27(20) V-18(0)-20(15)-27(20)

HOW IS AISI STEEL HARDNESS?

AISI Steel has medium carbon level with 0.38-0.43% Carbon.It has a surface hardness below 229HB  with annealed conditon.For  further applications,it needs higher hardness requirement for use.

Typical process for AISI steel is water/oil quench that can reach the hardness levels to  54-59HRC. But in actual production,medium-level hardness 28-32 HRC is widely used.

Another way for hardening this steel is Nitriding.With temperature 500-550℃,AISI Steel can get surface hardness up to 600-650HV.

IS AISI STEEL SUITABLE FOR SHAFTS?

Yes, AISI steel is widely used as an important material for crank shafts, tail shafts, marine propeller shafts, stern shafts and rudder spindles. This is because the alloy has an amazing strength to weight ratio and it also possesses good atmospheric corrosion resistance.

AISI Steel Shaft

WHICH MANUFACTURERS ARE RELIABLE FOR BUYING AISI STEEL?

There are numerous manufacturers and providers of AISI steel but you shouldn’t trust all of them. However, if you choose us for buying steel, we can take care of your needs.

We are the most reliable steel supplier in China and we have partnerships with renowned industries and businesses in the world. If you’re looking forward to buy high quality AISI steel in China, you’ll never get disappointed with us.

What We Supply For AISI Steel

Supply FormSize(mm)ProcessTolerance


RoundΦ6-Φ100Cold DrawnBright/Black Best H11
Φ16-Φ350
Hot RolledBlack-0/+1mm Peeled/ground Best H11
Φ90-Φ
Hot ForgedBlack-0/+5mm Rough Turned-0/+3mm
Flat/Square/BlockThickness :120-800
Hot ForgedBlack-0/+8mm Width:120-
Rough Machined-0/+3mm

Heat Treatment:Normalized(+N),Annealed(+A),Quenched & Tempered(+QT)

What Size We stock For AISI Steel

Size(mm)Length(mm)Size(mm)Length(mm)Size(mm)Length(mm) ΦΦΦ ΦΦΦ/ ΦΦΦ/ ΦΦΦ/ ΦΦΦ/ ΦΦΦ/

The steel that you will get from us is a comprehensive product of the best materials manufactured by alloying elements. We will cater to your needs wherever you are in the world.

With us, you’ll get high quality steel- you can also customize your steel orders according to your requirements. All you need to do us is to contact us and get a quotation.

For more Hiperco 50A alloy supplierinformation, please contact us. We will provide professional answers.

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