How to choose spring steel material?
Spring steel is selected on the basis of the section size of the spring, such as high carbon steel 65, suitable for production in the spring of 12 ~ 15mm under section 60CrMnA, suitable for the production of spring and the car less than 50mm in diameter with heavy-duty spring. The 30W4Cr2VA is used to make heat-resistant spring for work below 500 degrees centigrade. Generally, hot forming springs are generally quenched and tempered at moderate temperature to obtain a structure with a maximum elastic limit and fatigue properties
In choosing materials, the material shall be considered in combination with the diameter or thickness of the material. The size of commonly used spring steel in oil is shown in table 3-10.7mm below diameter carbon spring steel used for oil quenching, the size of all kinds of spring is slightly larger, available manganese spring steel quenching. Well, such as 65Mn spring steel 15mm diameter can be through quenching in oil, available water quenching diameter of 25mm. For the spiral spring, leaf spring and disc spring middle section can be used manganese spring steel, 60Si2Mn steel can be used as oil quenching diameter of 25mm, for the spring to withstand heavy loads with large cross section, can choose the hardenability of high chromium silicon steel, chrome vanadium steel wire, such as 60Si2CrA.50CrVA, 45mm in diameter can also through quenching in oil.
The cold plastic deformation of the cold drawn spring material is high, and most finished steel wires have reached the required mechanical properties when the steel mill is out of the factory. The surface quality of the steel wire is high, and the spring manufacturing process is simple. For springs of medium or small spring or high fatigue life, the cold spring or cold drawn spring or steel wire or strip shall be selected as far as possible. Carbon spring steel wire (group I, group II, group II A, dish group) and important uses of 65Mn spring steel wire during the cold drawing process caused in large residual stress, the larger the size change after low temperature tempering, and thus affect the dimensional accuracy of the spring. This kind of steel wire should be used preferentially for the tension spring with small bending radius and the compression spring with smaller diameter of steel wire. Oil tempered steel wire for residual stress, cold forming, precision spring is easy to control, low temperature tempering after the size change is very small, especially because there is no residual stress relaxation resistance than carbon spring steel wire lead quenching and cold drawing good. For the spring with higher size precision and the thicker diameter of spring steel and the good spring resistance, the oil quenching and tempering steel wire shall be used.
In determining the cross-section shape and size of spring materials, priority should be given to rejection of the national standards or ministerial standards for size specifications, as far as possible to avoid the use of non-standard specifications of materials. Although the spiral spring square or rectangular cross section material, the elastic deformation can be higher than, can make the small volume of the spring, for spring, in small space or under impact load but because of square or rectangular section material shortage, the price is higher, and the spring forming is difficult, so should be avoided. Ring section spring material diameter series see table 3-9.
Whether the spring is good or not is of great importance to the choice of the spring material. In general, selection of spring material, should take into account the load properties, spring force, various factors should be size, working conditions and price, etc..
