Patent ID: 8052919

Claim:
High frequency induction heating treatment equipment, comprising: temperature controlling means for adjusting an object in temperature, and; quenching determining means for determining when said object heated should be cooled, wherein: said temperature controlling means includes heating means heating said object through induction heating, first temperature measuring means involved in temperature control and measuring in temperature a portion of said object that is heated by said heating means, and temperature adjusting means connected to said first temperature measuring means to output a temperature control signal to said heating means, as based on information of temperature received from said first temperature measuring means; and said quenching determining means includes second temperature measuring means involved in quenching, and measuring in temperature a portion located away from said portion of said object that is heated by heating means, and heat treatment adjusting means connected to said second temperature measuring means to adjust a heating time, as based on temperature information received from said second temperature measuring means, and output a cooling start signal, wherein said heat treatment adjusting means is programmed to determine a diffusion length D ep of carbon by: D ep =A ×2( Dt ) 1/2 where D: a diffusion constant, t: a holding time (in seconds), A: a correction coefficient; D=D 0 exp(−Q/ RT ) where D 0 : an entropy term of said diffusion constant, Q: activation energy, R: a gas constant, T: absolute temperature (K); and erf ( A )=1−0.1573 C 1 /C 2 where C 1 : a solid solubility of carbon at 727° C., C 2 : a solid solubility of carbon at any temperature.