自2007年7月起，SAE航空航天材料部已宣布本规范“取消”，并已被AMS 2231取代。每当提及已取消的MAM 2231B时，应满足最新版AMS 2231的要求。通过这一行动，本文件仍将列在航空航天材料规范索引的数字部分，并指出其已被AMS 2231取代。本规范涵盖了适用于订购公制尺寸的碳钢棒材的既定公制制造公差。除非另有说明，否则这些公差适用于所有条件。 术语“excl”仅适用于指定范围内的较高数字。没有明确的界限来区分棒材和线材产品，因此不包括这些产品的定义。

This specification has been declared "CANCELLED" by the Aerospace Materials Division, SAE, as of July 2007, and has been superseded by AMS 2231. The requirements of the latest issue of AMS 2231 shall be fulfilled whenever reference is made to the cancelled MAM 2231B. By this action, this document will remain listed in the Numerical Section of the Index of Aerospace Material Specifications noting that it is superseded by AMS 2231.This specification covers established metric manufacturing tolerances applicable to carbon steel bars ordered to metric dimensions. These tolerances apply to all conditions, unless otherwise noted. The term "excl" is used to apply only to the higher figure of the specified range.No clear cut demarcation is available to differentiate between bar and wire products, therefore definitions of these products are not included.