55si2mn spring steel spring steel complete specifications 55si2mn affordable

Alloy carbon steel major strengthening element, the impact of spring steel often than any other alloying elements. According to requirements, spring steel material should be in high-carbon steel. The world today spring steel, widely used in the vast majority of the carbon content of 0.45% - 0.65%. To overcome after spring steel strength increased toughness and ductility reduce the problem, but also reduce the carbon content of the trend. China low-carbon martensitic spring steel-depth studies, such as 28mnsib, 35mnsib, with its carbon content of about 0.30%. Practice shows that these may be in the spring steel lath martensite tempering of use, there is sufficient strength and excellent mechanical properties, especially excellent ductility, toughness. Japanese research and development of several high-strength spring steel, such as uhs1900, vhs2000, nd120s, nd250s etc., carbon content of about 0.40 percent. The main role of alloying elements in steel spring is to improve the mechanical properties, improved process performance and giving some special properties (such as temperature, corrosion), etc. Many spring steel with silicon as the main alloying element, which is the largest bomb minus Resistance of alloying elements, mainly due to the silicon with a strong solid solution strengthening effect; at the same time, can inhibit crystal silicon cementite during tempering of nucleation and growth, tempering carbide precipitation when changing the number, size and shape, to improve stability of steel tempering. At present, the domestic steel grades in wsi 1.8% to 2.2%, which is the highest existing standards silicon spring steel. But silicon content is too high, will promote decarbonization of steel and graphite tendency in the process of rolling and heat treatment, and the smelting and easy form inclusions difficult, therefore, the use of high silicon content spring steel still cautious. Because chromium can significantly improve the steel hardenability, prevents si-cr ball annealing graphitization tendency to reduce carbon layer is therefore commonly used spring steel alloying elements, chromium as the main strengthening element of spring steel 50crv more extensive use. Manganese is most effective to improve hardenability alloying elements, which dissolved in the ferrite solid solubility of the action. Studies have shown that, wmn must be greater than 0.5%, so when hardened spring steel core section representing an entirely into martensite, but wmn exceeds 1.5%, toughness decreased significantly, which should be given priority in selection of spring steel. Mo can improve the steel hardenability, prevent temper brittleness, improve fatigue performance, few existing standards plus molybdenum spring steel, is generally added in an amount of 0.4% or less. Vanadium is a strong carbide forming elements, the solid state of the dispersed precipitated mc type carbide has a strong precipitation strengthening effect. Added 0.11% v in 35crmnb steel, can significantly improve the steel hardenability, also found that vanadium can reduce the sensitivity of decarburization 35simnb steel and vanadium that this reduces carbon steel effective solution to prevent grain growth and prevent grain boundary diffusion and improve the oxidation resistance related. Spring process performance under impact, vibration or stress in the long-term use of cross, it requires a high spring steel tensile strength, elastic limit, a 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. Definition of spring steel is 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.