4140 Steel

4140 steel is a chromium, molybdenum, manganese low alloy steel plate that is known for its toughness, high fatigue strength, and high torsional strength.

image

General Info About 4140 Steel

4140 steel is a low alloy steel plate that is used in many different industries.

  • Advantages/Disadvantages

    4140 steel plate has high fatigue strength, excellent toughness, and good corrosion resistance. One disadvantage to 4140 steel is the extra care that must be taken when welding it.

  • Industries

    4140 steel is used in the aerospace, oil and gas, and many other industries.

  • Applications

    4140 steel plate is often used for shafts, crankshafts, gears, collars, and machinery parts because of its toughness, abrasion and impact resistance, and high fatigue strength.

  • Machining

    4140 steel plate has good machinability in the annealed condition.

  • Welding

    4140 steel plate is weldable by all conventional methods but requires preheating beforehand.

  • Heat Treatment

    4140 is hardened by heating to 1550°F or 845°C followed by quenching in oil.

Typical Standards

TemperThickness (Metric/Imperial)
WidthLength
41403" - 10"36" - 96"96" - 240"

Chemical Properties

CrMnCSiMoSPFe
0.8 - 1.100.75 - 1.00.380 - 0.4300.15 - 0.300.15 - 0.250.0400.035Balance

Mechanical Properties

PropertiesMetricImperial
Tensile Strength655 MPa95,000 PSI
Yield Strength415 MPa60,200 PSI
Bulk Modulus140 GPa20,300 KSI
Shear Modulus80 GPa11,600 KSI
Elastic Modulus190 - 210 GPa26,557 - 30,458 KSI
Poisson's Ratio0.27 - 0.300.37 - 0.30
Elongation at Break (50mm)25.7%25.7%
Brinell Hardness197197
Machinability (set to AISI 1212 as 100 Machinable)6565

Frequently Asked Questions about 4140 Steel

  • Is 4140 a carbon steel?

    ANSWER:

    4140 steel is considered a low alloy or carbon steel. With the addition of chromium and molybdenum, it is one of the most common alloy steels. The chromium boosts corrosion resistance and the molybdenum boosts toughness.

  • Does 4140 steel rust?

    ANSWER:

    4140 steel has excellent resistance to corrosion compared to other types of steel because of its higher percentage of chromium and molybdenum. However, once the corrosion process has started, it will rust just like most steel that has undergone the same damage.

  • Can 4140 steel be welded?

    ANSWER:

    4140 steel can be welded but requires preheating beforehand because it is more crack sensitive.

  • What makes 4140 a "chromoly" steel?

    ANSWER:

    The addition of chromium and molybdenum are why 4140 is considered a “chromoly” steel.

  • What goes into the AISI 4140 designation?

    ANSWER:

    The first “4” is 4140 indicates that the steel contains molybdenum at higher levels than other steels like the 1xxx series.

    The “1” in 4140 indicates the addition of chromium at higher levels than 46xx steels.

    The “40” differentiates 4140 steel from other 41xx series steels.

Related Blog Posts

How to Calculate the Weight of a Steel Plate

To calculate the weight of a steel plate, you need to answer a few...

Read More

"Kloeckner Metals: The Wisdom of Troubled Times" - Boss Magazine

This article originally appeared in the June, 2020 issue of The Boss Magazine.  At...

Read More

10 Questions to Ask a Structural Steel Fabricator

When starting a new commercial or residential project, you will want the right structural...

Read More

Additional Steel Plate Grades

ABS A | ABS B
ABS A and ABS B are types...
ABS A131 AH36 | DH36 | EH36 | FH36
Higher-strength ABS shipbuilding steel comes in six...
API 2H Grade 50
API 2H Grade 50 is a structural...
AR450 | AR450F
AR450, or AR450F steel, is a high-carbon...
AR400 | AR400F
AR400, or AR400F steel, is a high-carbon...
AR500 | AR500F
AR500, or AR500F steel, is a high-carbon...
A633
A633 is high-strength low alloy structural steel...
A285
A285 is a carbon steel intended for...
AR600
AR600 steel is a durable high-carbon alloy...
AR200 | AR225 | AR235 | AR Medium
AR200, AR225, and AR235, all under the...
MIL-A-12560
MIL-A-12560 is a military spec armor steel...
UL NIJ Ballistic Tested Plate
Kloeckner Metals supplies UL NIJ Ballistic Tested...
MIL-A-46100
MIL-A-46100 is a military spec armor steel...
A710
A710 is a low-carbon, high-strength alloy steel...
A283
A283 is a low carbon structural steel...
SA612
SA612 is a high strength carbon steel...
SA537
SA537 is a heat treated steel plate...
SA516
SA516 is the most popular pressure vessel...
1045
1045 is a medium tensile steel that...
33 Max
33 Max is carbon plate that has...
A656
Kloeckner Metals routinely stocks A656 in four...
A871-65
A871-65 is an HSLA structural steel plate...
A588
A588 steel plate is a structural steel...
C1020 or 1020 Steel
C1020—also called 1020 steel plate—is a low...
A709
A709 is a high-strength, low-alloy steel plate...
A514
A514 steel plate—also known as T1 steel—is...
A516
A516 is the most popular pressure vessel...
A572
Kloeckner Metals routinely supplies A572, a high-strength,...
A36
A36 is a staple in the steel...

X

Outdated or Unsupported Browser Detected

The Kloeckner Metals website uses modern technologies. Unfortunately, your browser doesn't support those technologies.

Download the latest version of one of these browsers to experience the site:

Do Not Remind Me Later