3 Materials

Material is a fundamental link in the chain of ASME Code construction, and great care is taken to assure its quality. The ASME accomplishes this by adopting material specifications that have been developed and adopted first by the American Society for Testing and Materials, the ASTM. The ASME material specifications are thus usually identical to those of the ASTM. ASTM issues specifications designated by letter and number, for example, A-106, Seamless Carbon Steel Pipe for High Temperature Service. When the ASME adopts ASTM specifications, it adds the letter S. The equivalent ASME pipe specification is thus SA-106.

In keeping with the ASME's policy to internationalize its Code, ASME has adopted a number of foreign material specifications. These are included in Section II, Part A as a single cover sheet for each specification (a complete material specification has not been reproduced in Section II, Part A, as is done for the ASTM material specifications). For example, Section I permits the use of SA/AS 1548, Steel Plates for Pressure Vessel Equipment, an Australian Standard Material Specification. If a boiler manufacturer chooses to use one of the permitted foreign material specifications in the construction of his Section I component, then he will be obliged to obtain a copy of the relevant material specification.

The ASME or SA material specifications are used as purchase specifications. Each specification contains a variety of information appropriate to that product, dealing with how it is ordered, the manufacturing process, heat treatment, surface condition, chemical composition requirements, tensile requirements, hardness requirements, various test requirements, and how the material is to be marked. The purchaser can also specify nonmandatory supplementary requirements, dealing with such things as stress relieving, nondestructive examination, and additional testing. All of these requirements have evolved over the years in response to the needs of the users.