1.) The compression time of primary springs and drill pipe springs is 24 hours, and that of ordinary springs is 6 hours or 3~5 times of continuous compression, each time for 3~5 seconds. When pressing tightly, the gap between the spring and the mandrel should be 10% of the diameter of the mandrel. If the gap is too small, it will be difficult to operate. If the gap is too large, the spring will easily be bent and deformed. If one of the springs is broken during pressing, the rest should be reprocessed.

2.) For the multi-spring with large H0/D2 value, attention should be paid to its deformation during heat treatment, whether the mandrel should be worn or not, and the way of placement should be paid attention to, and appropriate heat treatment equipment should be selected. In the condition of repair, can be repeated tempering and hot pressing to achieve the purpose.

3.) Drill pipe springs and spring surface treatment are generally phosphating, and other treatments are also available. Where zinc and cadmium are to be coated, hydrogen removal treatment should be carried out after electroplating. After hydrogen removal treatment, 3% (not less than 3 pieces) should be pumped for retesting and standing treatment, and there should be no breakage during the retesting. Springs should be cleaned of surface dirt, salt marks, and scale. The method can be sand blowing or gasoline cleaning, but pickling cannot be used.

4.) Spring without supporting ring and wire diameter too small spring should not be welded spring head, but the end cable should not be obviously loose, should be deburring. Where the head of the multi-strand spring needs to be welded, the length of the welding part should be less than 3 times the cable diameter (the longest is not more than 10 mm). The heating length should be less than one circle, after welding should be polished smooth, welding parts should be local low temperature annealing during gas welding.

5.) According to the requirements of the product, the bearing ring can be selected by cold and hot parallel two methods. The spring is not allowed to be heated to spark or white by the thermal combining method, and the temperature of the silicon-manganese steel shall not be higher than 850℃. The bearing ring shall be in effective contact with the effective ring, and the gap shall not exceed 10% of the nominal gap between the rings.

6.) The characteristics of the multi-strand spring can be determined by adjusting the lead, and the cable distance can be adjusted as necessary during winding. The twist distance can be 3~14 times the wire diameter, but generally 8~13 times is better. The spring force is also closely related to the free height, the end ring, the outer diameter and the performance of the steel wire, which can be changed by adjusting one or several of them.