AISI 4140 steel Manufacturer and Exporter,supplied with round,square,flat,block,and shaft etc.AISI 4140 is defined as a low alloy steel which has 1% Cr-Mo as strengthening alloy elements.Compared with AISI 4130, it has a higher carbon content with good balance of strength, toughness ,abrasion and impact resistance and heat treatment capabilities,but poor in weldability characteristics.AISI 4140 is generally supplied in quenched and tempered condition with hardness 28-32HRC.AISI 4140 steel round bar

1.Supply Form & Size & Tolerance

Supply FormSize(mm)ProcessTolerance



Round
Φ6-Φ100Cold DrawnBright/Black Best H11

Φ16-Φ350

Hot Rolled
Black-0/+1mm
Peeled/ground Best H11

Φ90-Φ1000

Hot Forged
Black-0/+5mm
Rough Turned-0/+3mm

Flat/Square/Block
Thickness :120-800
Hot Forged
Black-0/+8mm
Width:120-1500
Rough Machined-0/+3mm

Remark:Tolerance can be customized as per requests

2.Chemical Composition

StandardGradeCSiMnPSCrNiMo
ASTM A2941400.38-0.430.15-0.350.75-1.00≤ 0.035≤ 0.040.8-1.10.15-0.25

EN10083
42CrMo4
0.38-0.45

≤ 0.4

0.6-0.90

≤ 0.025

≤ 0.035

0.9-1.2


0.15-0.30
1.7225
JIS G4105SCM4400.38-0.430.15-0.350.6-0.85≤ 0.035≤ 0.040.9-1.20.15-0.30
GB 307742CrMo0.38-0.450.17-0.370.5-0.80≤ 0.035≤ 0.0350.9-1.20.15-0.25
BS 970EN190.35-0.450.15-0.350.5-0.80≤ 0.035≤ 0.0350.9-1.50.2-0.40

3.Physical Property

Density g/cm37.85
Melting point °C1416
Poisson's ratio0.27-0.30
Machinability (AISI 1212 as 100% machinability)65%
Thermal expansion co-efficient µm/m°C12.2
Thermal conductivity W/(m.K)46
Modulus of elasticity 10^3 N/mm2210
Electric resistivity Ohm.mm2 /m0.19
Specific heat capacity J/(kg.K)460

Modulus of elasticity 10^3 N/mm2
100 ℃200 ℃300 ℃400 ℃500 ℃
205195185175165

Thermal expansion 10^6 m/(m.K)
100 ℃200 ℃300 ℃400 ℃500 ℃
11.112.112.913.513.9

4. Mechanical Property

Mechanical ConditionRSSTUVW
Ruling Section mm250250150100633020
Tensile Strength Mpa700-850770-930770-930850-1000930-10801000-11501080-1230
Yield Strength Mpa Min480540570655740835925
Elongation %15131513121212
Izod Impact J Min34275454474740
Charpy Impact J Min28225050424235
Hardness Brinell HB201-255233-277233-277248-302269-331293-352311-375

5.High Temperature Strength

For quenched and tempered heavy forgings

Diameter mm
Yield strength MPa
20 ℃100 ℃200 ℃250 ℃300 ℃350℃400℃
≤250510486461441422392363
250-500460431412402382353324
500-750390333333324304275245

6.Forging

Forging temperature should be carried out between 900℃-1200℃,The lower the forging-ending temperature ,the finer the grain size .Hold the temperature till uniform before forge,minimum forging temperature 850°C,so don’t forge below 850℃.AISI 4140 steel  should be cooled as slowly as possible in still air or in sand after forged.

7.Normalizing

Normalizing is used to refine the structure of forgings that might have cooled non-uniformly after forged,and considered as a conditioning treatment before final heat treatment.Normalizing temperature for AISI 4140 steel should be carried out between 870℃-900℃. hold suitable time for the steel to be thoroughly heated to  complete the ferrite to austenite transformation.Cool in still air.

8.Annealing

After Forged,AISI 4140 steel  may be annealed .Annealing temperature should be carried out between 800℃-850℃, hold suitable time for the steel to be thoroughly heated. Cool slowly in the furnace.This treatment will form a structure suitable for machining.The maximum Hardness is 241 HB.

9.Hardening

This heat treatment will obtain martensite structure  after quenched.It should be carried out between 840℃-875℃, hold suitable time for the steel to be thoroughly heated, soak for 10-15 minutes per 25 mm section, and quench in oil, water, or polymer as required.Tempering should be followed  immediately after quenched.

10.Tempering

Tempering is usually carried out to relieve stresses from the hardening process, but primarily to obtain the required  hardness and mechanical properties. The actual tempering temperature will be chosen to meet the required properties.Heat the AISI 4140 carefully to a suitable temperature ,usually between 550℃-700℃, soak at the temperature for 2 hours per 25mm of ruling section, then cool in air.Tempering between 250℃-375℃ is not avoided as tempering within this range will seriously reduce the impact value,result in temper brittleness .

11.Application

AISI 4140 steel finds many applications as forgings for the aerospace,oil and gas,automotive, agricultural and defense industries etc.
Typical applications for 4140 steel uses include:forged gears,spindles,fixtures,jigs,collars,Axles,conveyor parts,crow bars,logging parts,shafts,sprockets,studs,pinions,pump shafts, rams, and ring gears etc

AISI 4140 STEEL BUYING GUIDE

Are you in the market to buy AISI 4140 steel but you’re not sure of the reasons why you need it? If yes, here now we have prepared a comprehensive guide that will give you an overview of its properties, composition, applications, and much more.

4140 steel is known for its versatility and strength. Read our expert guide to get more insights on AISI 4140 steel. Following are the queries that you might have in your mind regarding the 4140 steel before buying.

By the end of this guide, you’ll not only be skilled to look at and distinguish 4140 steel, you will also have the knowledge in finding the best source for it.

4140 steel round bar

WHAT IS AISI 4140 STEEL GRADE DESIGNATION?

To understand the AISI 4140 steel properties, it is important to understand what the grade numbers in it mean. Following is the AISI 4140 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 4130 steel which has 0.30% carbon.

WHAT ARE EQUIVALENT GRADES FOR AISI 4140 STEEL?

We can see the international equivalent grades as below.Compared with AISI 4140 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 A2941400.38-0.430.15-0.350.75-1.00≤ 0.035≤ 0.040.8-1.10.15-0.25

EN10083
42CrMo4
0.38-0.45

≤ 0.4

0.6-0.90

≤ 0.025

≤ 0.035

0.9-1.2


0.15-0.30
1.7225
JIS G4105SCM4400.38-0.430.15-0.350.6-0.85≤ 0.035≤ 0.040.9-1.20.15-0.30
GB 307742CrMo0.38-0.450.17-0.370.5-0.80≤ 0.035≤ 0.0350.9-1.20.15-0.25
BS 970EN190.35-0.450.15-0.350.5-0.80≤ 0.035≤ 0.0350.9-1.50.2-0.40

For Further Disscussion:

CAN WE USE AISI 4140 STEEL  INSTEAD OF 42CrMo4 STEEL?

42CrMo4 is European grade from EN10083 standard,while AISI 4140 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 4140 and 42CrMo4

414042CrMo4Adjustment for 4140 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

42CrMo4 Steel Round Bar

WHAT IS THE DIFFERENCE BETWEEN AISI 4140 STEEL AND AISI 4130 STEEL?

From the AISI designation rules,First we know that 4140 has 0.4% percent carbon(0.38-0.43%) compared with 4130 which has lower o.3% carbon(0.28-0.33%).And also the Manganese is totally different,0.75-1.0% from 4140 compared with 0.4-0.6% from 4130.But with same amount of Molybdenum and Chromium added to AISI 4140 steel and AISI 4130 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 4130 steel is similar to 4140 steel but we can’t use them to replace.The 4140 steel has higher steel content as compared to 4130 steel. The 4140 steel also has greater strength and hardenability than 4130 steel. The welding ability of 4130 steel is better than 4140 but its wear-resistance performance is lower.Customers should consider what kind of performance you demand.

IS AISI 4140 STEEL HEAT TREATABLE?

Yes,As an alloy engineering steel,AISI 4140 steel is quite suitbale for heat treatment,The purposes for 4140 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 4140 steel, the treatment process can be divided into Normalizing,Annealing,and Quenching & Tempering.

Which Condition Should Be Normalized For AISI 4140 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 4140 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 4140 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 4140 steel normalizing

AISI 4140 Steel Round Bar Normalizing

What Is Differences Between Normalizing And Annealing For AISI 4140 Steel?

Normalizing and Annealing heat treatment process is quite commonly used in production for AISI 4140 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 4140 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 4140 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.

  • 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 4140 will be Slowly cooled down with furnace temperature in the furnace.

  • Surface Hardness

As the difference on the cooling rate,normalized 4140 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 4140 STEEL

Is AISI 4140 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 4140 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 4140 Steel Corrosion Resistant?

AISI 4140 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 4140 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 4140 Steel Machinable?

The AISI 4140 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 4140 Steel Weldability?

To weld the AISI 4140 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 4140 steel is not recommended in tempered condition (the condition in which it is normally supplied). If AISI 4140 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 4140 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 4140 steel can be welded using any commercial method as it has good weldability.

AISI 4140 Steel vs AISI 4145 Steel

The 4145 type of steel comes from the same family( Chromium-Molybdenum Series) of the AISI 4140 steel. The very small difference is their percentage of carbon content.AISI 4145 has carbon content with 0.43-0.48%,0.05% higher than AISI 4140 Steel.Due to the slight difference in carbon content, the strength of 4145 steel is slightly higher than that of 4140 steel.

With suitable heat treatment, AISI 4140 and AISI 4145 steel have good comprehensive performance,and are widely used in the oil and gas industry.

AISI 4145 Steel

AISI 4145 Forged Round Steel Bar

HOW IS THE CLEANLINESS FOR AISI 4140 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 4140 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 4140 STEEL SUITABLE FOR INDUCTION HARDENING?

Yes,AISI 4140 Steel can be applied with induction hardening with frequency 2500-8000HZ(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 4140 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 4140 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 4140 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 4140 Cold-drawn steel uses high-quality cemented carbide molds  to to ensure precise and uniform dimensional tolerances.

  • Surface Smooth

The surface of AISI 4140 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.

AISI 4140 Cold drawn steel

Dia 5/8 inch(15.88mm) Round steel for AISI 4140

  • 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 4140 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)1932
60K414(60,000)586(85,000)1835
75K517(75,000)655(95,000)1735

Hardness requirement for typical material grade

MaterialAPI Min.Yield/Min.HBWNACE Max.HBW
A105 Carbon Steel36K/140237
1040 Carbon Steel60K/174237
4130 Low Alloy Steel60K/174,75K/197237
4140 Low Alloy Steel60K/174,75K/197237
8630 Low Alloy Steel60K/174,75K/197237
410 Stainless Steel60K/174,75K/197237

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 4140 STEEL HARDNESS?

AISI 4140 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 4140 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 4140 Steel can get surface hardness up to 600-650HV.

IS AISI 4140 STEEL SUITABLE FOR SHAFTS?

Yes, AISI 4140 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 4140 steel shaft

AISI 4140 Steel Shaft

WHICH MANUFACTURERS ARE RELIABLE FOR BUYING AISI 4140 STEEL?

There are numerous manufacturers and providers of AISI 4140 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 4140 steel in China, you’ll never get disappointed with us.

What We Supply For AISI 4140 Steel

Supply FormSize(mm)ProcessTolerance



Round
Φ6-Φ100Cold DrawnBright/Black Best H11

Φ16-Φ350

Hot Rolled
Black-0/+1mm
Peeled/ground Best H11

Φ90-Φ1000

Hot Forged
Black-0/+5mm
Rough Turned-0/+3mm

Flat/Square/Block
Thickness :120-800
Hot Forged
Black-0/+8mm
Width:120-1500
Rough Machined-0/+3mm

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

What Size We stock For AISI 4140 Steel

Size(mm)Length(mm)Size(mm)Length(mm)Size(mm)Length(mm)
Φ1006000Φ1306000Φ1906000
Φ1056000Φ1406000Φ2006000/8000
Φ1106000Φ1506000Φ2106000/8000
Φ1156000Φ1606000Φ2206000/8000
Φ1206000Φ1706000Φ2306000/8000
Φ1256000Φ1806000Φ2406000/8000

The 4140 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 4140 steel orders according to your requirements. All you need to do us is to contact us and get a quotation.