Place the workpiece in a inductor which is wound with a hollow brass , after pass into the intermediate frequency or high frequency, alternating current is formed in the surface of the same frequency, the part surface is heated quickly (within a few seconds can be raised from 800 to 1000 degree water, the center remains close to room temperature) immediately after cooling (or oil immersion quenching), so that the surface layer hardened.
Heating frequency selection:
Room temperature induced current flows into the workpiece surface layerdepth δ (mm) and the current frequency f (HZ) frequency, currentpenetration, decrease, deep hardening layer lower.
Current frequency are commonly used:
1, high-frequency heating: 100~500KHZ, 200~300KHZ, tube-type high-frequencyheating, hardened, deeply 0.5~2.5mm, suitable for small and medium sizedparts.
2, intermediate frequency heating: current frequency for the 500~10000HZ,2500~8000HZ, power supply device for the mechanical medium frequency heatingdevice or thyristor intermediate frequency generator. Hardening depth 2~10mm. Suitable for large-diameter shafts, gear and so on.
3, power-frequency heating: electric current frequency of 50HZ. Bymechanical power-frequency heating power supply equipment, hardened layerdepth up to 10~20mm, suitable for large-diameter workpieces in surfacehardening.
Application of induction heating quenching:
Compared with the ordinary heating and quenching with:
1, heats very quickly, expanding the scope of a transition temperature,shorten the time of transition.
2, hardening the workpiece surface layer can be very thin cryptocrystallinemartensite, hardness is slightly higher (2~3HRC). Brittle lower and higherfatigue strength.
3, with the workpiece easy oxidation and decarburization process, even someartifacts can be assembled directly after use.
4, hardened layer depth, easy to control operation, ease of mechanisationand automation.
Flame surface hardening:
Suitable for medium carbon steel 35, 45 carbon steel and alloyed structuralsteel 40Cr, 65Mn, flame hardening of grey cast iron, alloy cast iron. Iswith gas-oxygen or acetylene-oxygen mixture combustion flame heating theworkpiece. After quenching temperature is reached the surface of theworkpiece, cooling water immediately. Hardened layer depth is 2~6mm,otherwise it will cause serious overheating and deformation of crack on thesurface of the workpiece.
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Emily