Spring steel is mainly good elasticity, but also because it is moving under load environmental conditions of work, so the main material for producing spring should have a high yield strength; when subjected to heavy load does not cause plastic deformation; proper high fatigue strength, under the action of a load repeatedly with a long life; and have sufficient toughness and ductility to prevent brittle fracture under sudden impact force. Spring steel refers to steel due to the elasticity in the quenched and tempered condition, and specifically for the manufacture of springs and elastic components. Spring steel depends on its ability to elastically deform, i.e., within the prescribed range, the ability to withstand a certain elastic deformation so that the load does not occur in the permanent deformation after the load is removed. Spring steel should have excellent properties such as mechanical properties (especially elastic limit, ultimate strength, yield ratio), ballistic performance reduction (ie anti decreased elasticity properties, also known as sag resistance), fatigue properties, hardenability physical and chemical properties (heat resistance, low temperature, oxidation, corrosion, etc.). To meet these performance requirements, spring steel with excellent metallurgical quality (high purity and uniformity), good surface quality (strict control of surface defects and decarburization), the exact shape and size. According to GB / T 13304 "Steel classification" standard, according to the basic performance characteristics and use of a spring steel is a mechanical structural steel; according to quality grade, is a special quality of steel, that is, in the production process requires strict control of the quality and performance of special steel . According to Chinese custom, spring steel is a special steel, spring steel production when the technical requirements are relatively high, excellent technology directly determine the level of quality. Spring steel spring under the impact, vibration or stress for long-term deposit, 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 silicon content Wsi improve performance; in addition to Ge, tungsten, vanadium alloy spring steel. In recent years, with China's resources, and designed according to the requirements of new technology cars, 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 . Performance requirements for use in the spring under the impact, vibration, or long-term cross-stress, 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 silicon content Wsi improve performance; in addition to Ge, tungsten, vanadium alloy spring steel. In recent years, with China's resources, and designed according to the requirements of new technology cars, 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 is generally 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. Thus, when the thermal processing temperature should not stop rolling low (≥850 ℃), easier to avoid the formation of graphitization temperature range (650 ~ 800 ℃) long residence time. Rear springs made by shot peening make spring surface residual compressive stresses 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. Process specification steel quenching temperature quenching medium hardness tempering temperature of the cooling medium hardness range of applications 65780-830 water or oil 400-600 12-15mm diameter smaller than a coil spring, spring washers 65Mn810-830 oil or water> 60370- 400 water lamina and coil springs 42-50 5-10mm of 7-10mm of 50CrV850-870 oil> 58400-55 45-50 large cross-section of water and more important lamina and the coil spring 50CrV850-870 oil> 58 370-420 45-52 300C operating below the high temperature spring 60Si2MnA860-880 oil> 60500-520 water HB363-444 8-12mm thickness of the lamina