Steel wire for mechanical springs; part 3: oil-hardened and tempered wire

This standard establishes the technical requirements and test methods for oil-quenched and tempered steel wire used in spring manufacturing. It focuses on the specific metallurgical properties necessary to ensure consistent performance in dynamic loading applications. The document outlines classification criteria based on diameter ranges and specifies minimum values for tensile strength, yield strength, and elongation. Furthermore, it details procedures for surface quality inspection, including the assessment of surface defects such as cracks, seams, and inclusions. Dimensional tolerances for wire diameter and deviations are also defined to support precision engineering needs. The standard addresses the microstructure and hardness requirements essential for the intended heat treatment process. It provides guidelines for sampling techniques and laboratory testing protocols to verify compliance with the specified mechanical properties. These provisions aim to facilitate uniformity in product quality across global supply chains. The content serves as a reference for manufacturers, suppliers, and quality control laboratories involved in the production and evaluation of this specific type of spring wire material.