The ASTM system for designating metals consists of the letter (A - for ferrous metals), followed by an arbitrary number, usually three digits. These designations are often applied to specific products., eg, A 548 applies to cold rolled quality carbon steel wire for making screws for fastening sheet metal. Metric versions of ASTM standards have a suffix letter M.
Example of ASTM steel designation
ASTM A 582/A 582M-95b, Grade 303S - Automatic Stainless Steel Bars.
- A: denotes ferrous metal without division into cast iron, carbon steel, alloy steel or stainless steel.
- 582: serial number of the standard without any relation to the properties of the metal.
- M: indicates, that the A 582M standard is written in metric units of the SI system (the letter "M" comes from the word "Metric"). The designation A 582 / A 582M indicates, that the standard includes both systems of units - inch-pounds and metric.
- 95: indicates the year of adoption of the standard or its last revision. Letter b after year indicates, that this is already the third edition of the standard in 1995 year.
- (2000): the number in brackets indicates the year of the last revision of the standard.
- Grade 303Se: indicates the grade of steel and in this case then, that steel has a selenium additive.
Stamps, types and grades of steel
In the steel industry, brand terms, type and class are defined as follows. steel grade serves to describe the chemical composition of steel. The type of steel is used to indicate the characteristics of steel production, eg, method of steel deoxidation. Steel grade can be used to indicate other characteristics, such as, strength or surface finish.
Example 1: Steel grades A, ASTM A 106-02a B and C - Carbon Steel Tubes for Elevated Temperature Service:
1) Usually with increasing order in the alphabet (since A, IN, FROM) steel grades have increased strength or yield strength. For unalloyed steels, this means an increase in carbon content..
2) In this case:
– brand A: 0,25 % carbon (Max.); strength limit 48 ksi (minim.);
– brand B: 0,30 % carbon (Max.); strength limit 60 ksi (minim.);
– brand C: 0,35 % carbon (Max.); strength limit 70 ksi (minim.).
Example 2: Steel types 304, 316, 410 according to ASTM A 276-03 - Bars and profiles made of stainless and heat-resistant steel:
– types of steel 304, 316NS 410 and others are based on the SAE designation system for stainless steels (former SAE and AISI designations).
When designating steels for pipes and forgings, additional letters are used before the digital code of the steel grade:
- P: pipes for pipelines (pipes);
- T: structural pipes (tubes);
- TR: pipes of all types;
- F: forgings.
Examples of 3:
- Steel grade P22 according to ASTM A 335 / A 335M-03: Seamless stainless ferritic steel pipes.
- Steel grade T22 according to ASTM A 213 / A 213M-03a: Seamless ferritic steel pipes for operation at elevated temperatures.
- Steel grade TP304 according to ASTM A 312 / A 312M-03: Seamless and welded austenitic steel pipes.
- Steel grade F22 according to ASTM A 336M-03a: Alloy steel forgings for pressure and elevated temperature applications.
Source: Handbook of Comparative World Steel Standards /John E. Bringas, ASTM International, 2004.