When selecting a hospital instrument spring, it must be determined by the load nature, stress size, stress state, environmental medium, working temperature, life span, rules of electric conduction and magnetism, process performance, material and its price, etc.

When determining the shape of the material section and its size, the size specified by the state must be selected first, and non-standard materials should not be selected. For medium and small medical equipment in the spring, the key is spiral extension spring, strengthen treatment of steel wire is the first selected, such as lead bath temperature drawn wire and its oil quenching tempering steel wire, has a very high intensity and good surface quality, fatigue performance than ordinary quenching tempering steel wire, is very simple, process performance is very good, quality is stable.

Carbon cable spring steel wire and piano steel wire will cause a very large residual stress after cold drawing, after the spring processing, there will be a very large multiplier residual stress, after tempering the size change is very large, it is difficult to control the dimensional precision. Oil quenching and tempering steel wire is in the steel wire is in the steel wire after drawing to the specified size to carry out the modulation and strengthening treatment, basically no residual stress exists, after forming the spring through low temperature tempering, the size change is small, the heat resistance stability is better than cold drawing steel wire.

Large and medium-sized medical device springs should be cold-drawn or cold-drawn polished steel for higher load accuracy and stress. Hot rolled steel can be used for springs with low load accuracy and stress.