This specification covers the highest quality of round modified chromium vanadium alloy steel valve spring wires, uniform in quality and temper, intended for the manufacture of valve springs and other springs requiring high-fatigue properties when used at moderately elevated temperatures. This wire shall either be in the annealed and cold-drawn or oil-tempered condition. The steel shall be subjected to continuous casting and be free from detrimental pipe and undue segregation. Heat and product analysis shall conform to the chemical requirements for carbon, manganese, phosphorus, sulfur, silicon, chromium, and vanadium. Mechanical properties shall be determined by the following: annealing and cold-drawing, oil tempering, wrap testing, and special surface inspection. In the oil-tempered condition, steel shall conform to the tensile requirements for different wire diameters. Metallurgical characterization shall include surface condition, decarburization, and inclusion content. The wire or wire rod shall conform to the maximum inclusion content requirements for the surface and core zones.

1.1 This specification covers the highest quality of round and shaped modified chromium vanadium alloy steel valve spring wire, uniform in quality and temper, intended for the manufacture of valve springs and other springs requiring high-fatigue properties when used at moderately elevated temperatures. 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. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independent 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.