Study on the Diffusion of carbon in Ni - Cr - Mo Steel by Autoradiography
박용진Yong Jin Park, 김상주Sang Joo Kim
Abstract
The diffusion of carbon in Ni-Cr-Mo steel teas studied by autoradiography. The alloys were melted using high purity low carbon steel. The high carbon alloys were made by the addition of low-activity C^(14) (diluted to 0.050 m Ci per g). After casting into steel moulds and forging all alloys were homogenized in argon for 24 hrs at 1400℃ or 1280℃. Diffusion couples were welded with Toyoda Frictional Welder. After the diffusion couples were annealed they were sectioned along their cylindrical axes. The faces were exposed to X-ray film for some 12 days. Diffusion coefficients of carbon in 3.0% Ni-0.8% Cr-0.3% Mo steel at various temperatures are 10^(-8)∼10^(-7)㎠/sec. It is concluded that the autoradiographic technique can be effectively used to determine the effect of strong carbide-forming alloying elements on the diffusion rate of carbon in austenite.