FOREWORD This Code of Metallurgical Terms for Ferrous Alloys was prepared by the Topical Committee on Materials of the Central Committee on Drilling and Production Practice@ Division of Production@ American Petroleum Institute@ to promote uniformity of meaning in the usage of metallurgical terms when applied to oil field equipment. The Institute requests the cooperation of suppliers of oil field equipment in the elimination of uncertainty and confusion by restricting the use of these terms to their accepted meaning. In the compilation of this code free use was made of the publications of the American Society for Testing Materials@ American Society for Metals@ Society of Automotive Engineers@ and various textbooks of Metallurgy@ Metallography@ and Properties of Materials. Full acknowledgement is hereby made to these sources of information and appreciation is expressed for the permission freely granted by those societies for its use.