In this post I'll talk about SAE 4340. First let's describe it and then have a look at its material's properties.
What is SAE 4340?
SAE 4340 alloy steel is a heat treatable and low alloy steel containing chromium, nickel and molybdenum. It has high toughness and strength in the heat treated condition.Application
SAE 4340 alloy steel is mainly used in power transmission gears and shafts, aircraft landing gear, and other structural parts.UNS Number
G43400Ok let's start with SAE 4340 Chemical Composition.
Chemical Composition
C, Carbon
0.38–0.43Mn, Manganese
0.60–0.80P, Phosphorus max.
0.040S, Sulfur max.
0.040Si, Silicon
0.15–0.35Ni, Nickel
1.65–2.00Cr, Chromium
0.70–0.90Mo, Molybdenum
0.20–0.30Learn more about Chemical Composition.
Now it's the mechanical properties turn:
Yield Strength
470 - 1150 MPaLearn more about Yield Strength.
Tensile Strength
690 - 1280 MPaLearn more about Tensile Strength.
Elongation (min.)
12 - 22%.Learn more about Elongation.
Hardness
Brinell
210 - 360Learn 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 4340 currently ranks 28 in my yield strength index. This means there are other 27 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 4340 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 6359 AMS 6454 ASTM A331 (4340) ASTM A711 SAE J1397 (4340)
AMS 6409 ASTM A29 (4340) ASTM A506 (4340) ASTM A752 (4340) SAE J404 (4340)
AMS 6414 ASTM A320 (L43) ASTM A519 (4340) ASTM A829 SAE J412 (4340)
AMS 6415 ASTM A322 (4340) ASTM A646 (4340-7) MIL S-5000
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