SAE 4140 Properties (Chem., Mech. & Rankings) 2022

 

In this post I'll talk about SAE 4140. First let's describe it and then have a look at its material's properties.

What is SAE 4140?

SAE 4140 alloy steel is a chromium, molybdenum, and manganese containing low alloy steel. It has high fatigue strength, abrasion and impact resistance, toughness, and torsional strength.

Application

They are used in oil and gas, energy, construction and the automotive industries because of its corrosion resistance and high-temperature and tensile strength.

UNS Number

G41400

Ok let's start with SAE 4140 Chemical Composition.

Chemical Composition

C, Carbon

0.38–0.43

Mn, Manganese

0.75–1.00

P, Phosphorus max.

0.040

S, Sulfur max.

0.040

Si, Silicon

0.15–0.35

Cr, Chromium

0.80–1.10

Mo, Molybdenum

0.15–0.25

Learn more about Chemical Composition.

Now it's the mechanical properties turn:

Yield Strength

Typical properties

90 ksi, 621 MPa (Hot Rolled). 100 ksi, 689 MPa (Stress Relieved). 60 ksi, 414 MPa (Annealed). 90 ksi, 621 MPa (Normalized)

Learn more about Yield Strength.

Tensile Strength

Typical properties

120 ksi, 855 MPa (Hot Rolled). 120 ksi, 855 MPa (Stress Relieved). 80 ksi, 552 MPa (Annealed). 120 ksi, 855 MPa (Normalized)

Learn more about Tensile Strength.

Elongation (min.) 50 mm typical

15% (Hot Rolled). 10% (Stress Relieved). 25% (Annealed). 20% (Normalized).

Learn more about Elongation.

Hardness

Typical Rockwell

100 HRB (Hot Rolled). 100 HRB (Stress Relieved). 85 HRB (Annealed). 100 HRB (Normalized)

Learn more about Hardness.

Density

7.8 g/cm3.

Learn more about Density.

Elastic Modulus

190 GPa.

Learn more about Elastic Modulus.

Poisson's ratio

0.29.

Learn more about Poisson's ratio.

Allowable Stress or Factor of Safety

Depends on the project (And its factor of safety).

Learn more about Allowable Stress or Factor of Safety.

My Material's Ranking Research

While engineers will often look for the cheapest material they can use, I took a different approach to material's selection to help newbie students.

I ranked materials according to their yield strengths and SAE 4140 currently ranks 13 in my yield strength index. This means there are other 12 materials that are more resistant.

Note: I've analysed 162 materials in order to create an yield strength index. Check my material's comparison post for more details.

SAE Classroom

Are you having trouble understanding the basics of SAE?

What is SAE: Classification and specification?

This video will walk you through:

References

ASTM A519 and other references.

Citation

When you need to include a fact or piece of information in an assignment or essay you should also include where and how you found that piece of information.

That gives credibility to your paper and it is sometimes required in higher education.

To make your life (and citation) easier just copy and paste the information below into your assignment or essay:

Luz, Gelson. SAE 4140 Properties (Chem., Mech. & Rankings). Materials Blog. Gelsonluz.com. dd mmmm. yyyy. URL

Now replace dd, mmmm and yyyy with the day, month, and year you browsed this page. Also replace URL for the actual url of this page. This citation format is based on MLA.

Equivalent Specifications

AMS 6349 ASTM A193 (B7, B7M) ASTM A506 (4140) ASTM A752 (4140)⁣
AMS 6381 ASTM A194 (7, 7M) ASTM A513 ASTM A829⁣
AMS 6382 ASTM A29 (4140) ASTM A513 (4140) SAE J1397 (4140)⁣
AMS 6390 ASTM A320 (L7, L7M, L7D) ASTM A519 (4140) SAE J404 (4140)⁣
AMS 6395 ASTM A322 (4140) ASTM A646 (4140) SAE J412 (4140)⁣
AMS 6529 ASTM A331 (4140) ASTM A711⁣