Process characteristics of the hottest multi stran

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Process characteristics of multi strand spring

due to the limitation of product structure, multi strand spring generally has the characteristics of high strength and good performance. The material is required to guarantee the final performance in terms of strength and toughness. Therefore, the elastic modulus e=206 is usually selected as the material × 103n/mm2 carbon spring steel wire shape drawing (gb4357) or carbon spring steel wire (gb4360). The specific specification of steel wire shall be determined according to the structural characteristics and load requirements of the product

according to the number of steel wire strands, multi strand springs can be divided into three strands and four strands, among which three strands are common

there are two methods of winding multi strand springs: one is to screw the steel rope and wind the spring at the same time; The other is to screw the steel rope and wind the spring step by step, that is, screw the steel rope first, and then wind the spring. The steel rope can be screwed and wound on the lathe respectively, and it can also be wound on the machine tool with automatic wire rope screwing mechanism at the same time

its typical process can be referred to as follows:

loading → (screwing the steel rope) → winding → cutting → grinding head → appearance inspection → surface treatment (depending on the product requirements and whether the welding head is welded) → welding two ends (as required) → filing the welding head (as required) → merging the end ring (merging) → correction → heat treatment → tightening → correction → trimming the end ring (as required) → inspection → surface treatment (there is no such process for those who have undergone surface treatment) → the calculation of typical process parameters of oil immersion

can be carried out according to the following formula:

1. Calculation formula of steel wire development length:

l1= (π dn1m)/(COS) α cos β)

d--------- pitch diameter of spring (mm)

n1--------- total number of turns

α--------- Spiral rise angle (°)

m--------- number of spring strands

β------- Wire rope tightening angle (°)

2. Stiffness calculation formula:

p`= (gd4mi)/(8d3n)

g--------- shear modulus (n/mm2), generally 79 × 103~85 × 103

d--------- diameter of steel wire (mm)

i----------- cable twisting coefficient, when m=3, β At 15 ° ~25 °, take 1.05~1.2; When m produces harmful volatiles =4, β At 20 ° ~30 °, take 1.1~1.3

n----------- number of effective coils

in the processing process, the following points should be paid attention to:

1. Springs without support rings and springs with too thin steel wire diameter should not be welded with spring heads, but the steel cables at the ends should not be obviously loose and should be deburred. For multi strand springs with welded heads, the length of the welded part shall be less than 3 times the cable diameter (the longest shall not be more than 10mm). The heating length shall be less than one circle, and it shall be polished and smooth after welding. During gas welding, the welded parts shall be locally annealed at low temperature

2. According to the product requirements, the support ring can be cold combined and hot combined. It is not allowed to heat the spring to spark or whiten by heating, and the temperature of silicon manganese steel shall not be higher than 850 ℃. The bearing ring should be in effective contact with the effective ring, and the gap should not exceed the nominal gap between the rings. The new Daron reg is launched by Allianz; RTM10%。

3. Some things we do may look very simple. The characteristics of the strand spring can be determined by adjusting the lead, and the cable distance can be adjusted when winding. The screw pitch can be 3-14 times the diameter of steel wire, but generally 8-13 times is preferred. The spring force is also closely related to the free height, parallel end ring, outer diameter and steel wire performance, which can be changed by adjusting one or more of them

4. The tightening time of important springs is 24 hours, and that of ordinary springs is 6 hours or continuously compressed for 3-5 times, each time for 3-5 seconds. During tightening, the gap between the spring and the mandrel should be 10% of the mandrel diameter. If the gap is too small, it is difficult to operate, and if the gap is too large, it is easy to bend and deform the spring. If one of the springs is broken during tightening, the rest should be reprocessed

5. For multi strand springs with large h0/d2 value, pay attention to their deformation during heat treatment, consider whether to wear the mandrel, pay attention to the placement method, and select appropriate heat treatment equipment. Under the condition that repair can be carried out, multiple tempering and hot pressing can be carried out to achieve the purpose

6. Generally, phosphating treatment can be carried out for spring surface treatment, and other treatments can also be carried out. Where the coating is zinc and cadmium, dehydrogenation treatment should be carried out after electroplating. After dehydrogenation, 3% (not less than 3 pieces) should be sampled for retest and standing treatment. There should be no fracture in the retest. The spring shall be cleaned of dirt, salt marks and oxide skin on the surface by sand blowing or gasoline cleaning, but acid pickling is not allowed. (end)

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