Performance requirements
Spring under the impact, vibration, or long-term cross-stress use, it requires a high spring steel tensile strength, elastic limit, high fatigue strength. In the process requires a certain degree of spring steel hardenability, easy removal, good surface quality carbon spring steel that is the carbon content of WC within 0.6% -0.9% range of high-quality carbon structural steel. Silicomanganese alloy spring steel is mainly the Department of steel, their lower carbon content, mainly by increasing the silicon content Wsi improve performance; in addition to Ge, tungsten, vanadium alloy spring steel. In recent years, combined with our resources, and design requirements for new technology based on automobiles, tractors, developed a boron, niobium, molybdenum and other elements on the basis of in silico-manganese steel new steel to extend the spring of life and improve the quality of the spring .

Production Process
Usually available spring steel furnace, open-hearth, or oxygen converter production; better quality or have special properties of high-quality spring steel, electric furnace or vacuum furnace slag refining. The main provisions of spring steel elements carbon, manganese, silicon and other content narrower, must strictly control the chemical composition of smelting. Easy to form bubbles and other defects at higher silicon content, after cooling wrought ingot was not easy to produce white spots. Therefore, the smelting of raw materials must be dry, try to remove gas and inclusions, but also to avoid superheat. Spring steel surface decarburization and pay special attention to the quality of the rolling process. When the steel surface decarbonization serious, it will significantly reduce the fatigue limit of steel. For high silicon spring steel as 70Si3MnA, should be taken to avoid graphitization. Therefore, when the thermal processing temperature should not stop rolling low (≥850 ℃), avoiding graphitization easily formed in a temperature range (650 ~ 800 ℃) long residence time. Rear springs made by shot peening springs make the surface residual compressive stress, to offset part of the work on the surface stress, inhibit the formation of surface cracks, which can significantly increase the fatigue limit of the spring.