ASME vs. ASTM materials standard

In this article, I will explain about what are the differences between ASME and ASTM materials standard. At the end of the article, you will not mix up SA106 Gr B with A106 Gr B.

As you know, ASME has not developed an independent standard for materials, but only the letter S is added in front of the relevant ASTM standard number to show that this standard is in accordance with the ASME code. Two parts of Section II of the ASME BPVC is dedicated to these standards, which includes Part A for ferrous metals and Part B for non-ferrous metals.

All these standards can be classified into three groups:

The first group includes standards that are similar in ASME and ASTM, which emphasize the sameness of the two standards by mentioning a sentence, and there are two standard logos, as shown in the below.

The second group has editorial differences or other minor differences that are not decisive. In this case, while mentioning the differences, only the ASME logo is visible.

In the standards of the third group, there are major differences or differences that are decisive.

For example, consider this last case. If your design code is ASME SEC VIII-div.1 and you declare the material B335 in the purchase order (PO), the manufacturer or vendor is not required to certify the product and furnish a test report, while by declaring SB335, you will have product certificate and test report.

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Now, let me raise an interesting related issue.

It can be said that A283 Grade C steel plate after A516 Grade 70 is the most widely used material for the construction of atmospheric storage tanks and pressure vessels, and all those working in the oil, gas, petrochemical and power plant industries are familiar with this grade.

There is an important tip in the use of this ASTM standard, and that is the need to pay attention to the scope of that because four grades A, B, C, and D were always listed as grades of this standard, but in 2012 revision, two grades of lower strength, A and B, were removed from the standard and only grades C and D remained.

Another important change (from 2013 revision) is the addition of a clause to section 4 of the standard that steel shall be killed. Prior to the 2013 edition, it was also produced as a rimmed plate, and if you wanted to order plates other than rimmed or capped, you had to mention the supplementary requirements (SR) to S97.1.

As you know, the deoxidation practice of steel is very decisive and because of the importance of the issue, the requirement that steel not be rimmed is in many codes and specifications, including in API 650 or BS 5500. This is not explicitly mentioned in ASME Sec VIII.

Although ASME has not developed an independent standard for materials and only adds the letter S in front of the corresponding ASTM standard number, we should not think that we can blindly put an S in front of the ASTM grade to convert it to ASME. As you see in the below picture, ASME mentions that it does not recognize the latest changes to ASTM A283 and only accepts the 2003 (reapproved 2007) edition! This means that the choice of deoxidation practice by the client are still in place.

Well... Apparently, we have no choice but to adapt to these changes, so remember that if we order steel based on the latest revision of ASTM A283, we only have two grades D and C and on the other hand, we have a not rimmed steel plate, but if order based on ASME SA283, remember not to neglect S97.1