General methods or devices for heat treatments

CCHEMISTRY METALLURGY C21Iron metallurgy C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHER TREATMENTS

C21D1/00General methods or devices for heat treatments

C21D1/02Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation C21D1/04with simultaneous application of supersonic waves, magnetic or electric fields C21D1/06Surface hardening C21D1/08with flames C21D1/09by direct application of electrical or wave energy by particle radiation C21D1/10by electric induction C21D1/18Hardening Quenching with or without subsequent tempering C21D1/185from an intercritical temperature C21D1/19by interrupted quenching C21D1/20Isothermal quenching C21D1/22Martempering C21D1/25Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius C21D1/26Methods of annealing C21D1/28Normalising C21D1/30Stress-relieving C21D1/32Soft annealing C21D1/34Methods of heating C21D1/38Heating by cathodic discharges C21D1/40Direct resistance heating C21D1/42Induction heating C21D1/44in heat-treatment baths C21D1/46Salt baths C21D1/48Metal baths C21D1/50Oil baths C21D1/52with flames C21D1/53Heating in fluidised beds C21D1/54Determining when the hardening temperature has been reached by measurement of magnetic or electrical properties C21D1/55Hardenability tests C21D1/56characterised by the quenching agents C21D1/58Oils C21D1/60Aqueous agents C21D1/607Molten salts C21D1/613Gases Liquefied or solidified normally gaseous material C21D1/62Quenching devices C21D1/63for bath quenching C21D1/64with circulating liquids C21D1/667for spray quenching C21D1/673for die quenching C21D1/68Temporary coatings or embedding materials applied before or during heat treatment C21D1/70while heating or quenching C21D1/72during chemical change of surfaces C21D1/74Methods of treatment in inert gas, controlled atmosphere, vacuum, or pulverulent material C21D1/76Adjusting the composition of the atmosphere C21D1/763using a catalyst C21D1/767with forced gas circulation Reheating thereof C21D1/773under reduced pressure or vacuum C21D1/78Combined heat-treatments not provided for above C21D1/785Thermocycling C21D1/82Descaling by thermal stresses C21D1/84Controlled slow cooling