How to select spring steel wire
The selection of spring material shall be determined according to the nature of the load borne by the spring, stress state, stress size, working temperature, environmental medium, service life, requirements for conductivity and magnetic conductivity, process performance, material source, price and other factors.
When determining the section shape and size of materials, priority shall be given to the series sizes specified in national standards and ministerial standards, and materials with non-standard series specifications shall be avoided as far as possible.
Medium and small-sized springs, especially spiral tension springs, shall give priority to the strengthened steel wire, lead bath isothermal cold drawn steel wire and oil quenched and tempered steel wire, which has high strength and good surface quality, higher fatigue performance than ordinary quenched and tempered steel wire, simple processing, good workmanship and stable quality.
The carbon spring steel wire and Piano steel wire produce large residual stress after cold drawing. After processing the spring, there is large residual stress, and the size changes greatly after tempering, so it is difficult to control the dimensional accuracy. Oil quenched and tempered steel wire is modulated and strengthened after the steel wire is drawn to the specified size, and there is basically no residual stress. After low-temperature tempering after forming the spring, the size change is very small, and the heat resistance stability is better than that of cold drawn reinforced steel wire.
For large and medium-sized springs with high load accuracy and stress, cold drawn materials or polished steel after cold drawing shall be selected. Hot rolled steel can be used for springs with low load accuracy and stress.
Flat steel of 55si2mn, 60Si2MnA, 55SiMnVB, 55simnmov, 60crmn, 60crmnb and other brands are generally selected for leaf spring.
For the material section of coil spring, circular section shall be preferred. Square and rectangular section materials have strong bearing capacity and good impact resistance, and can miniaturize the spring, but there are few sources of materials. And the price is high. Except for special needs, this material is generally not selected as far as possible. In recent years, the development of flattening round steel wire instead of trapezoidal steel wire has achieved good results.
