GCR9SIMN spring steel high-wear spring steel bar: 1. Performance requirements ① high elastic limit σe and yield ratio σs / σb, in order to ensure good elastic properties, which can not absorb large amounts of elastic plastic deformation; ② high The fatigue limit, fatigue is the main failure mode of the spring, the fatigue properties of addition and composition of the steel structure of the outside, but mainly by the steel metallurgical quality (such as non-metallic inclusions) and spring surface quality (such as decarbonization) effects; ③ sufficient ductility and toughness to prevent impact fracture; ④ other properties, such as good heat treatment and plastic processing performance, work under special conditions of heat or corrosion resistance requirements. 2.composition characteristics of carbon and alloying elements in steel content and the role is to: 1., Generally carbon, carbon spring steel wc = 0.6% ~ 0.9%, alloy spring steel wc = 0.45% ~ 0.70%, after quenching Canada obtained after tempering tempering troostite organizations can better ensure the performance requirements of the spring. (2) general purpose alloy alloying elements are generally low alloy spring steel. Main add elements Si, Mn, Cr, etc., whose main role is to enhance hardenability, solid solution strengthening of the matrix and improve the tempering stability; add elements Mo, W, V and other strong carbide forming elements, the main role decarburization prevent defects caused by Si, Mn defects caused by overheating and to improve the tempering stability and heat resistance. 1 carbon spring steel (ie non-alloy spring steel) its cheap but poor hardenability, suitable for non-critical section size smaller springs, of which 65,65 Mn most commonly used. 2 alloy spring steel under the main alloying elements can be divided into two different types of categories: Si-Mn and Cr-based spring steel spring steel. The former hardenability than steel, the price is not very expensive, it is the most widely used, mainly for the cross-sectional dimension of not more than 25mm of various types of springs, 60Si2Mn is a typical representative; latter better hardenability, mechanical properties high surface decarburization spring, but the price is relatively high, generally used for larger cross-sectional dimension of the important spring, 50CrVA is a typical representative. 4 characteristics of spring steel heat treatment depends on the processing method of forming a spring, and can be divided into hot springs and cold formed springs forming two categories: 1. Hot forming spring-sectional dimension> 10mm variety of large and complex shape of the spring are using hot forming (such as hot-rolled, hot rolled), such as automobiles, tractors, trains spring and coil springs. The simple processing route: flat or round bar cutting bending or winding → → heating quenching temperature tempering → surface peening treatment, use of state organizations is tempered troostite. Shot can enhance the surface quality of the surface and improve the spring, significantly improved the fatigue performance. 2 spring cold forming sectional dimension <10mm various small spring can be cold formed (such as cold rolled, cold rolled), such as the instrument of the coil spring, spring, and spring and so on. Before the forming of such springs for cold drawn (rolled), quenching and tempering in the temperature or lead bath temperature after quenching cold drawn (rolled) strengthening; then cold forming process, this process will further strengthen the metal, but also produced the large internal stress and brittleness, it should be carried out in a subsequent stress relief annealing temperature (usually 200 ~ 400 ℃).