Brief analysis of the precautions in spring processing
1. Springs without bearing rings and springs with too small wire diameters shall not be welded with the spring head, but the end wire shall not have obvious looseness and burr. For multi strand spring with welding head, the length of welding part shall be less than 3 times of cable diameter (generally not more than 10mm). The heating length shall be less than one circle and shall be polished smooth after welding. During gas welding, low-temperature local annealing shall be conducted for the welding part.
2. According to product requirements, the support ring can be cold and hot. Thermal bonding is not allowed to heat the spring to spark or turn white, and the temperature of silicon manganese steel shall not be higher than 850. The support ring shall be in effective contact with the effective ring, and the clearance shall not exceed 10% of the nominal clearance between rings.
3. The characteristics of the multi strand spring can be determined through adjustment, and the cable distance can be adjusted during winding. The screw pitch may be 3-14 times the diameter of the steel wire, but generally 8-13 times is preferable. The spring force is also closely related to the free height, end lap, outer diameter and steel wire performance, and can be changed by adjusting one or more of them.
4. The pressurization time of important springs is 24 hours, and the pressurization time of ordinary springs is 6 hours or 3-5 times continuously, 3-5 seconds each time. During pressing, the clearance between the spring and the mandrel shall be 10% of the mandrel diameter. If the clearance is too small, it is difficult to operate. If the clearance is too large, it is easy to cause bending and deformation of the spring. If one of the springs breaks during pressing, the rest shall be reworked.
5. For multi strand springs with large H0 / D2 value, pay attention to the deformation during heat treatment, whether the mandrel is worn and how to place it, and select appropriate heat treatment equipment. If it can be repaired, multiple tempering and hot pressing can be carried out to achieve the purpose.
6. Phosphating or other treatments can be used for the surface treatment of general springs. When the plating is zinc and cadmium, it shall be dehydrogenated after plating. After dehydrogenation, 3% (not less than 3 pieces) were taken for retest and treated standing. There was no fracture in the retest. Dirt, salt marks and scale on the spring surface shall be removed. The method can be sand blasting or gasoline cleaning, but not acid washing.
