The development of spring application technology puts forward higher requirements for materials. It mainly improves fatigue life and anti relaxation performance under high stress; Secondly, according to different applications, it is required to have corrosion resistance, non-magnetic, electrical conductivity, wear resistance, heat resistance, etc. Therefore, in addition to developing new types of spring materials, beneficial results have also been achieved in strictly controlling chemical composition, reducing non-metallic inclusions, improving surface quality and dimensional accuracy.
1.SUS304
1) Stainless steel spring wire refers to the steel specially used for manufacturing springs and elastic elements due to its elasticity under quenching and tempering conditions. The elasticity of steel depends on its ability of elastic deformation, that is, within the specified range, the ability of elastic deformation enables it to bear a certain load, and there is no permanent deformation after the load is removed.
2) Application fields: the designed and produced stainless steel springs are applied to spray springs, high-temperature springs, battery welding, stainless steel compression springs, tension springs, torsion springs, high-strength springs, high fatigue springs, medical springs, non-magnetic springs and braided springs
2. Development of electroplated steel wire
In special cases, in addition to spring characteristics, additional properties such as corrosion resistance and conductivity are required, which are mostly solved by electroplating process.
The corrosion resistance of some stainless steel wires and Piano wires is equivalent to that of zinc plating. If another layer of ZnAl (5%) alloy is plated, the corrosion resistance can be increased by about 3 times.
For stainless steel wire or piano wire with resistance performance requirements, the wire diameter less than 0.4mm can be plated with copper, and the wire diameter greater than 0.4mm can be plated with copper inside and stainless steel outside. The general piano steel wire is plated with 5 thick Ni to improve its conductivity.
Generally speaking, processes that can harden materials to form residual stress (such as shot peening and surface nitriding) can improve fatigue strength. At present, electroless Ni plating is being studied. By heating (300-500 ℃), 7% of P can be precipitated as PNI, and the Vickers hardness can be increased to HV500. After shot peening, if Ni plating is heated below 300 ℃, the hardness can also be increased by 10%.
