What is ASTM A638?ASTM A638 is a Specification for Precipitation Hardening Iron Base Superalloy Bars, Forgings, and Forging Stock for High-Temperature Service.
CategoryCorrosion-Resisting and Heat-Resisting Steels
ScopeThis 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.
Cr13.50 - 16.00
Ni24.0 - 27.00
Mo1.00 - 1.50
Ti1.90 - 2.35
V0.10 - 0.50
B0.0010 - 0.010
Learn more about chemical composition.
Now it's the mechanical properties turn:
Grade 66085 ksi (585 MPa) min.
Learn more about what is yield strength.
Grade 660130 ksi (895 MPa) min.
Learn more about what is tensile strength.
Elongation (min.) 4D0.15.
Learn more about what is elongation.
Reduction of Area (min. %)0.18.
Learn more about reduction of area.
Grade 660248 HB min.
Learn more about what is hardness.
Allowable StressDepends on the project (And its factor of safety).
Learn more about the what is allowable stress.
My Material's RankWhile 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.
ASTM ClassroomAre you having trouble understanding the basics of ASTM?
What is the difference between Code, Standard & Specification?
This video will walk you through:
CitationWhen 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 ReferencesA 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