ASTM Explanation

ASTM Standard Logo

The ASTM's system for metals consists of a letter (A for ferrous materials, B for nonferrous materials) followed by an arbitrary sequentially assigned number. Metric ASTM standards have a suffix letter M.

For instance:

ASTM A 516/A 516M-90 (2001) Grade 70 - Pressure Vessel Plates, Carbon Steel, for Moderate- and Lower-Temperature Service:

• The "A" describes a ferrous metal, but unfortunately it does not sub-classify it as cast iron, carbon steel, alloy steel, or stainless steel.

• 516 is a sequential number without any relationship to the metal’s properties.

• The "M" indicates that the standard A 516M is written in rationalized SI units (the "M" comes from the word "Metric"), hence together A 516/A 516M utilizes both inch-pound and SI units.

• 90 indicates the year of adoption or last revision.

• (2001) number in parentheses indicates the year of last reapproval.

• Grade 70 indicates the minimum tensile strength in ksi, 70 ksi or 70,000 psi.