ASTM A320 Properties (Chem., Mech. & Rankings) 2022

In this post I'll talk about and give details about ASTM A320. First let's describe it and then have a look at its material's properties.

What is ASTM A320?

ASTM A320 is a Specification for Alloy-Steel and Stainless Steel Bolting for Low-Temperature Service.

Category

Corrosion-Resisting and Heat-Resisting Steels

Scope

This specification covers alloy steel bolting for pressure vessels, valves, flanges, and fittings for low-temperature service.

Ok let's start with ASTM A320 chemical composition.

Chemical Composition

Grade L7

C

0.38 - 0.48

Mn

0.75 - 1.00

P max.

0.035

S max.

0.040

Si

0.15 - 0.35

Cr

0.80 - 1.10

Mo

0.15 - 0.25

Learn more about chemical composition.

Now it's the mechanical properties turn:

Yield Strength

Grade L7

105 ksi (725 MPa) min

Learn more about what is yield strength.

Tensile Strength

Grade L7

125 ksi (860 MPa) min

Learn more about what is tensile strength.

Elongation (min.) 50 mm

0.16.

Learn more about what is elongation.

Reduction of Area (min. %)

0.5.

Learn more about reduction of area.

Hardness Requirements

Grade L7

321 HBW or 35 HRC max

Learn more about what is hardness.

Impact Requirements

Grade L7

27J minimum

Learn more about impact testing (charpy v notch).

Other properties:

Density

7480 - 8000 kg/m3 (around 7.9 g/cm3 or 0.285 lb/in3).

Learn more about density.

Elastic Modulus

180 GPa (26107 ksi) - 210GPa (30458 ksi).

Learn more about the Elastic Modulus.

Poisson's Ratio

Usually around 0.26 – 0.31.

Learn more about the poisson ratio.

Allowable Stress

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

Learn more about the what is allowable stress.

My Material's Rank

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 ASTM A320 currently ranks 6 in my yield strength index. This means there are other 5 materials that are more resistant.

Note: I've analysed 134 materials in order to create an yield strength index. Check my astm material's comparison post for more details.

Details and PDF

Instructions:

1. Go to this page.
2. Type the name of the standard you are looking for in the search box. Tip: Don't forget to include "ASTM" as a keyword.
3. Read the details about the standard or download the PDF.

ASTM Classroom

Are you having trouble understanding the basics of ASTM?

What is the difference between Code, Standard & Specification?

This video will walk you through:

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 & paste the information below into your assignment or essay:

Luz, Gelson. ASTM A320 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 (The < and > stay, ok?). This citation format is based on MLA.

Other References

A194/A194M Specification for Carbon and Alloy Steel Nuts⁣
for Bolts for High Pressure or High Temperature Service,⁣
or Both⁣
A370 Test Methods and Definitions for Mechanical Testing⁣
of Steel Products⁣
A962/A962M Specification for Common Requirements for⁣
Bolting Intended for Use at Any Temperature from Cryogenic⁣
to the Creep Range⁣
E566 Practice for Electromagnetic (Eddy-Current) Sorting⁣
of Ferrous Metals⁣
F436 Specification for Hardened Steel Washers⁣
F606 Test Methods for Determining the Mechanical Properties⁣
of Externally and Internally Threaded Fasteners,⁣
Washers, Direct Tension Indicators, and Rivets⁣