金屬熱處理를 위한 高溫面의 膜沸騰急冷却에 관한 硏究 (第1報, 炭素鋼 켄칭 過程의 冷却曲線과 過渡沸騰熱傳達)

A Study on the Film Boiling-Quenching Process of the Hot Surface for the Heat Treatment of Metals (1st Report, Cooling Curves and Transient Boiling Heat Transfer during the Quenching Process of Carbon Steel)

The quenching of steels by water is one of the important problems in engineering for the applications of heat treatment or continuous casting process, but the fundamental researches by the theoretical approaches have not been satisfactorily improved yet. The very rapid cooling problems by the thermal conduction including the latent heat of phase transformation in steel and the transient boiling heat transfer of water on the surface of the steel covering from $850^{\circ}C$ to $20^{\circ}C$ are the key problems of heat treatment. The present quenching experiments are performed for the cylindrical specimens of carbon steel, S45C of diameters (12-30). Nonlinear transient heat conduction and transient boiling heat transfer problem of water on the surface of specimens is analyzed by the numerical method of inverse heat conduction problem. The conditions for the calculation are that the initial temperature of specimens is $820^{\circ}C$ and the cooling water in bath are $20^{\circ}C$,$40^{\circ}C$,$60^{\circ}C$,$80^{\circ}C$,$95^{\circ}C$ with no agitation.