Due to the limitations of the product structure, multi-strand springs are generally characterized by high strength and good performance. Requirements for its materials in the spring strength and toughness of the final performance to be guaranteed. Multi-stranded spring in the process, it should be noted that:
1, the support ring according to product requirements can be selected from cold and hot and two methods. The use of hot and do not allow the spring heated to sparking or whitening, silicon manganese steel temperature shall not be higher than 850 ℃. Support circle and effective circle should be effective contact, the gap shall not exceed 10% of the nominal gap between the circle.
2, multi-stranded spring characteristics can be determined by adjusting the lead, winding the cable distance can be adjusted as necessary. Screwing distance can be taken 3 ~ 14 times the diameter of the wire, but generally take 8 ~ 13 times better. The spring force is also closely related to the free height, and the end of the circle, the outer diameter and wire performance, etc., can be changed by adjusting one or more of them.
3, without support ring spring and steel wire diameter is too thin spring should not be welded spring head, but the end of the steel wire should not be obviously loose, should be deburred. Where the need to weld the head of the multi-stranded spring, the length of the welding part should be less than 3 times the diameter of the cable (maximum length of not more than 10 mm). Heating length should be less than a circle, after welding should be polished smooth, gas welding welding parts should be localized low-temperature annealing.
4, spring surface treatment can be generally phosphated, but also other treatments. Where to be plated with zinc and cadmium, plating should be dehydrogenated, dehydrogenated draw 3% (not less than 3 pieces) retesting the treatment, retesting shall not be fractured. Spring should be removed from the surface dirt, salt scars, oxide skin, the method can be used to blow sand or gasoline cleaning methods, but can not be used to pickling. 5, the important spring tightening time of 24 hours, ordinary springs for 6 hours or continuous compression of 3 to 5 times, each time to maintain 3 to 5 seconds. Tighten the spring and mandrel clearance to 10% of the diameter of the mandrel is appropriate, the gap is too small is difficult to operate, the gap is too large is easy to make the spring bending deformation. If one of the spring breaks when tightening, the rest should be reprocessed.