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.
ApplicationThey are used in oil and gas, energy, construction and the automotive industries because of its corrosion resistance and high-temperature and tensile strength.
Ok let's start with SAE 4140 Chemical Composition.
P, Phosphorus max.0.040
S, Sulfur max.0.040
Learn more about Chemical Composition.
Now it's the mechanical properties turn:
Typical properties90 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.
Typical properties120 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 typical15% (Hot Rolled). 10% (Stress Relieved). 25% (Annealed). 20% (Normalized).
Learn more about Elongation.
Typical Rockwell100 HRB (Hot Rolled). 100 HRB (Stress Relieved). 85 HRB (Annealed). 100 HRB (Normalized)
Learn more about Hardness.
Learn more about Density.
Elastic Modulus190 GPa.
Learn more about Elastic Modulus.
Learn more about Poisson's ratio.
Allowable Stress or Factor of SafetyDepends on the project (And its factor of safety).
Learn more about Allowable Stress or Factor of Safety.
My Material's Ranking ResearchWhile 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 ClassroomAre you having trouble understanding the basics of SAE?
What is SAE: Classification and specification?
This video will walk you through:
ReferencesASTM A519 and other references.
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Equivalent SpecificationsAMS 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