This specification deals with the highest quality of round carbon steel spring wire, uniform in quality and temper, intended especially for the manufacture of valve springs and other springs requiring high-fatigue properties. The steel wire shall be subjected to continuous casting, hardening, and tempering to produce the desired mechanical properties. The steel shall conform to the chemical requirements for carbon, manganese, phosphorus, sulfur, and silicon. Mechanical properties shall be determined by the tension test, wrap test, twist test, and special surface inspection. The material as represented by tension test specimens shall conform to the tensile requirements for tensile strength and reduction of area. Metallurgical characterization of steel shall include decarburization, surface condition, and microstructure.

1.1 This specification covers the highest quality of round and shaped carbon steel spring wire, uniform in quality and temper, intended especially for the manufacture of valve springs and other springs requiring high-fatigue properties. It is similar to the grade VD (referenced in EN 10270-2) intended for high fatigue levels. This wire shall be either in the annealed and cold-drawn or quenched and tempered condition as specified by purchaser.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.