On certain occasions, need to spring is beyond the conventional need elasticity, such as spring for carrying firearms, and the use of spring in the space is very small, stretch to meet, it is necessary to use high tensile strength, good resistance to steel wire spring production, "particularly uses carbon spring steel wire is used" the need for standards.
This standard is supplied by 3 groups of steel wire, nail, B and C. Group C used to high stress spring, group B used to spring with high stress, a suitable for super high stress spring. Standard recommended steel wire is made by T9A, T10A and T8MnA. Practice on the tensile strength of steel wire with carbon content increase, change function (tolerance policy) with carbon content increased and decreased, summed up, especially Liaoning Steel Group Dalian three steel companies to use the steel wire with rare earth T9A produced a, B and C group of steel wire.
About that ultra high tensile strength of steel wire is at the expense of some plastic and fatigue life in return, only applies to the production of simple shape, on the fatigue life need spring is not very high, the standard should not be used. Table 6 standard for GJB 1497-92 extra use carbon spring steel wire
Explain:
(1)The difference of tensile strength between ends of each steel wire shall not exceed 100Mpa.
(2)When the steel wire is changed, no visible cracks and delamination can be observed within the regulation change times.
(3) coil test of steel wire, the steel wire can not break and split after coiling 1~5 circle around mandrel. Mandrel diameter equal to steel wire diameter.
