熔融鋳鉄の水素分析用試料採取法

抄録

Various sampling methods for determination of hydrogen in molten cast iron (2.63∼3.41%C, 1.40∼1.88%Si) have been compared. The samplers used were the vacuum sampler, the modified Taylor sampler, the silica tube and two kinds of copper moulds (6×6×65 mm, 15 mm dia. by 75 mm long). After solidification the drawn or poured iron was quenched in mercury. Among these samplers, the vacuum sampler is most complicated, but it seems to be most reliable. The hydrogen in the samples was extracted by the hot-extraction technique at 1000°C, and determined by the palladium-tube method. The results obtained were as follows: (1) When the hydrogen content is less than 8 p.p.m., the results obtained with the vacuum sampler coincide with those obtained with the modified Taylor sampler. The values obtained with the copper moulds are a little lower than those obtained with the two samplers mentioned above. The values obtained with the silica tube agree fairly well with those obtained with the modified Taylor sampler when the iron contains up to 3 p.p.m. of dissolved hydrogen, but when the hydrogen content is larger, the silica tube methods gives considerably lower hydrogen content than that obtained with the modified Taylor sampler. (2) The standard deviation of the results obtained with the modified Taylor sampler is 0.23 p.p.m. within the range of hydrogen content from 1.7 to 3.4 p.p.m.