| 摘要 |
PURPOSE:To enable subtle fluctuations in decarburization annealing conditions to be easily detected by cutting a sample out of a sheet subjected to decarburization annealing in a weakly oxidizing atmosphere and by dipping the sample in an etching soln. to measure electrode displacement or an electic current yielded between the sample and a reference opposite electrode. CONSTITUTION:Sample 2 of about 3X3 cm is cut out of a sheet subjected to decarburization annealing in a weakly oxidizing atmosphere, and sample 2 is dipped in an etching soln. such as about 2-20% aq. slon. of sulfuric acid. The soln. is held at a fixed temp. of room temp.-about 95 deg.C, and electrode displacement or an electric current is measured which is yielded between sample 2 and reference opposite electrode 1 dipped at the same time. Oxide on the surface of electrode 1 is removed well in advance. An electromotive force-time curve is diplayed by a potential difference recorder. Thus, by previously investigating a change in a curve pattern in case decarburization annealing conditions are fluctuated, condition fluctuating factors can be indicated concretely. |
