The ASME Codes and material specifications include specific requirements for use of the materials in ASME Code construction. However, they do not address all requirements. It is the responsibility of the user to specify service related requirements to prevent in-service degradation of the materials. It is the responsibility of the vessel manufacturer to account for materials degradation during fabrication and to include all necessary requirements in the raw material purchase specifications for ASME Code construction. The scope of this document is to discuss the requirements in the ASME Codes and in the ASME material specifications for metallic materials, to address the various issues that affect the materials, and to provide guidelines for evaluating materials manufacturers and for preparing materials specifications that include the requirements for procuring material for ASME Code construction. Some of the sections in this document pertain only to ferrous materials (carbon steels, low alloy steels and high alloy steels) because many of the past problems have been related to these materials (refer to Section 4 and Section 11 herein). However, most of the issues and considerations discussed in this document also pertain to nonferrous materials, particularly Sections 12 - 14 herein.