ASTM A638 Properties (Chem., Mech. & Rankings) 2022

In this post I'll talk about and give details about ASTM A638. First let's describe it and then have a look at its material's properties.

What is ASTM A638?

ASTM A638 is a Specification for Precipitation Hardening Iron Base Superalloy Bars, Forgings, and Forging Stock for High-Temperature Service.

Category

Corrosion-Resisting and Heat-Resisting Steels

Scope

This specification covers hot-finished or cold-finished precipitation hardening iron base super alloy bars, forgings, and forging stock for high-temperature service.

Ok let's start with ASTM A638 chemical composition.

Chemical Composition

Grade 660

C max.

0.08

Mn max.

2.00

Si max.

1.00

P Max.

0.040

S max.

0.030

Cr

13.50 - 16.00

Ni

24.0 - 27.00

Mo

1.00 - 1.50

Ti

1.90 - 2.35

Al max.

0.35

V

0.10 - 0.50

B

0.0010 - 0.010

Learn more about chemical composition.

Now it's the mechanical properties turn:

Yield Strength

Grade 660

85 ksi (585 MPa) min.

Learn more about what is yield strength.

Tensile Strength

Grade 660

130 ksi (895 MPa) min.

Learn more about what is tensile strength.

Elongation (min.) 4D

0.15.

Learn more about what is elongation.

Reduction of Area (min. %)

0.18.

Learn more about reduction of area.

Hardness Requirements

Grade 660

248 HB min.

Learn more about what is hardness.

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 A638 currently ranks 21 in my yield strength index. This means there are other 20 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 A638 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

A 484/A 484M Specification for General Requirements⁣
for Stainless Steel Bars, Billets, and Forgings⁣
A 751 Test Methods, Practices, and Terminology for⁣
Chemical Analysis of Steel Products⁣
E 30 Test Methods for Chemical Analysis of Steel, Cast⁣
Iron, Open-Hearth Iron, and Wrought Iron⁣