ASTM and AISI Standards Carbon and Alloy Steel Grades Representation

In ASTM, SAE, AISI standard, representation of carbon steel and alloy steel grades is the same basically. Mostly used four Arabic numerals, sometimes add the letter in the middle or the end, for example: 1005,94B15,3140. The first two digits of the four digits indicate the type of steel and major alloying elements, The last two digits indicate the average carbon content.

1. The first digit (or the first and second digit) represents the following categories: 1 - carbon steel, 2-nickel steel, 3-nickel-chromium steel, 4-molybdenum steel, 5-chromium steel, 61- chrome vanadium steel, 8- low nickel chromium steel, 92- silico-manganese steel, 93,94,97,98-chrome-nickel-molybdenum steel

2. The second digit represents steel or alloy element content: we give a few examples.

Carbon Steel: 0- general carbon steel, 1- cutting steel, 3- manganese steel.

Molybdenum steel: 1- chromium molybdenum steel, 3 and 7 - nickel-chromium-molybdenum steel, 6 and 8-nickel-molybdenum steel, 0,4,5- containing different amounts of Mo-Mo steel.

3. The fourth digits indicate the average carbon content, with the millionth.

For example, AISI 4130 is a low alloy steel containing molybdenum and chromium as strengthening agents. In addition, we can offer AISI 4130 steel pipe, ASTM A335 alloy pipes, ASTM/AISI standard alloy round bar.