Abstract
For the determination of hydrogen in steel, the high-frequency fusion impulse-furnace fusion method using the graphite crucible is currently employed because of its rapidity. Comparing with the results by the heat extraction method using no graphite crucible, those by above methods agree with standard values in the case of standard samples stainless steel but are inclined to be higher in the case of samples taken from melts (mold samples). In mold samples, fine cracks and blow-holes are often contained where water is included during the storage and preparation of samples. As the result of the reaction between the included water and the graphite crucible (water gas reaction), involved hydrogen is accumulated to the resultant value of hydrogen.
For elimination of th included water, authors invent the pre-heat device. The included water in samples eliminated by the heating (300-350°C) and at the same time, the diffused hydrogen is collected to determine.
Using the improved method, the determination of hydrogen is carried out exactly although the sample contains some blow-holes. This method requires only eight minutes for one determination and gives the good accuracy (standard deviation=0.1ppm H2 at 2.5ppm).
