(1) Judgment heat treatment
Judgment heat treatment refers to the release of a tensile stress field equivalent to 30%~50% of the tensile strength on both sides of the heat-treated stainless steel wire. At this time, the interstitial solute atoms (C and N) diffuse near the dislocation line by temperature, "pinning" the moving dislocation. In addition, the diffusely melted cementite during the heat treatment process provides a lot of pinning points, which makes the dislocation "pinning" more complete and abundant, improves the plastic deformation immunity of stainless steel wire, and improves the elastic reduction characteristics of stainless steel wire.
(2) Electromagnetic heating treatment
Electromagnetic heating is rapid, the diazotization reaction on the surface of stainless steel wire is light, it is not easy to cause nitriding, and the crystallization is also improved. The compression spring is made of oil quenching and tempering-heat treatment stainless steel wire produced and processed by intermediate frequency induction furnace, which has very good plasticity and elastic reduction characteristics under static load and load, and the net weight is reduced by 10%~20% under the condition that the various indicators of the spring remain at the original level. The rubber shock absorber factory is very much alloy steel containing vanadium and niobium, and only by using a higher metallographic structure temperature to fully dissolve vanadium and niobium can the expected effect of secondary hardening of heat treatment be obtained. Under the general temperature increase standard, the metallographic microstructure temperature is too high, the crystallization of stainless steel wire is coarsen, and the diazotization reaction and nitriding on the surface are also greatly aggravated, which seriously threatens the tired service period. When the electromagnetic heating reaches 900~1200 °C, the stainless steel wire is not easy to nitride, severe diazotization reaction and crystallization roughening. Therefore, electromagnetic heating can make full use of the advantages of alloy steels containing vanadium and niobium.
