Processing for compression springs
Compression springs is normally processed through shot blasting and hot treatment.
1. Shot blasting: transfer compression spring to blasting chamber by belt conveyor one by one, inside which there is one group of parallel roller rails. The roller rails are rolling while strengthening, which will drive the rotating and moving of compression springs. The rotation will make the blasting flow go to the middle of every winding and the surface, where is the stress focus part. After blasting, the fatigue life of the high stress springs will be increased 4 times.
2. hot treatment
Working conditions and requirements for materials and hot treatment
1) Condition: springs with simple shape, small fracture, less stress
Requirements: 65 785-815℃ oil quenching, 300℃400℃、500℃ tempering, relative hardness HB512, HB430, HB369; 75,780-800℃ oil or water quenching, 400-420℃ tempering, HRC42-48.
2) Condition: large springs with middle load
Requirements: 60Si2MnA65Mn 870℃ oil quenching, 460℃ tempering, HRC40-45(agricultural set springs: 65Mn quenching and tempering , HB280-370).
3) Condition: large leaf springs and spiral springs with heavy load, high fatigue limit
Requirements: 50CrVA, 60SiMnA 860℃ oil quenching, 475℃ tempering, HRC40-45.
4) Condition: coil springs whose diameter is 8-10mm when working at various load changing conditions.
Requirements: 50CrMnA840-870℃ oil quenching, 450-480℃ tempering, HB387-418.
5) Condition: engines, cars, tenders or leaf springs
Requirements: 55SiMn、60Si2Mn HRC39-45(hb363-432)(Jiefang’s automotive:55Si2Mn HB363-441)
6) Condition: cars, buffering spiral springs and tension springs
Requirements: 55Si2Mn, 60Si2Mn, 60Si2CrA quenching, tempering, HRC40-47 or HB370-441.
7) Condition: diesel pump plunger springs, oil injector springs, agricultural diesel engine valve springs and medium, heavy car valve springs and leaf springs.
Requirements: 50CrVA quenching, tempering, HRC40-47
8) Condition: coil springs and flat springs working at high steam temperature, springs of water pipe and seawater erosion resistance springs, Φ10-25mm
Requirements: 3Cr13HRC39-46 4Cr13 HRC48-50 HRC48-49 HRC47-49 HRC37-40 HRC31-35 HRC33-47
9) Condition: springs working with acid and alkali medium
Requirements: 2Cr18Ni91100-1150℃ water quenching, eliminate stress after coiled, 400℃ tempering for 60min, HB160-200
10) Condition: elastic collarδ4,Φ85
Requirements: 60Si2 400℃ preheating, 860℃ oil quenching, 460℃ tempering and air cooling, HRC40-45.