The selection of spring material should be determined according to the load nature, stress state, stress size, working temperature, environmental medium, service life, requirements for conductive and magnetic conductivity, process performance, material source and price
When determining the shape and size of material section, the series size specified by national standard and ministry standard should be preferred, and the material with non-standard series specification should be avoided as far as possible
Medium and small-sized springs, especially spiral tension springs, should be preferentially reinforced steel wire, lead bath isothermal cold drawn steel wire and oil quenched and tempered steel wire, which have higher strength and good surface quality, higher fatigue performance than ordinary quenching and tempering steel wire, simple processing, good technology and stable quality
After cold drawing, carbon spring steel wire and Piano steel wire produce large residual stress. After processing the spring, there is large residual stress. After tempering, the size changes greatly, so it is difficult to control the size accuracy. Oil quenching and tempering steel wire is used to modulate and strengthen the steel wire after drawing to the specified size, and there is basically no residual stress. After forming the spring, it is tempered at low temperature, and the size change is very small, The heat resistance stability is better than that of cold drawn reinforced steel wire
For large and medium-sized springs, cold drawn steel or polished steel after cold drawing should be selected for those with high load accuracy and stress. For springs with low load accuracy and stress, hot-rolled steel can be selected
The flat steel of 55si2mn, 60Si2MnA, 55SiMnVB, 55simnmov, 60crmn, 60crmnb, etc. are generally used for leaf spring
Circular cross-section should be preferred for spiral spring material section. Square and rectangular cross-section materials have strong bearing capacity, good impact resistance, and can make spring miniaturization, but the material source is small and the price is high. Except for special needs, this material is generally not selected. In recent years, the development of round steel wire instead of trapezoidal steel wire has achieved good results