| 摘要 |
PURPOSE:To obtain an accurate analytical value of O2 in steel by removing a surface oxide film, by heating a sample steel piece to a specific temp. or more under a reductive gaseous atmosphere within a reaction pipe to perform the reduction treatment of only the surface of said steel piece. CONSTITUTION:A sample for analysis of O2 in steel has oxide on the surface thereof due to air oxidation caused by processing heat or friction heat generated during the cutting of the sample. Hereupon, a cap 3 is detached and a sample steel piece 6 is put in the boat 5 in a reaction tube main body 2 having a diameter reduced gas exhaust port 7 at one end side thereof and, after the cap 3 is again fitted to said main body 2, H2-gas is sent into the reaction tube main body 2 from an inlet 1 while the temp. of a heating furnace 8 is controlled by using a thermocouple 4 to reduce only the surface of the steel piece 6. For example, reduction is performed at 600 deg.C for about 30sec to perfectly reduce the surface oxide film of the steel piece 6. After reduction is completed, the steel piece 6 is cooled while H2-gas is replaced with inert gas such as Ar-gas to supply the cooled steel piece to an oxygen analyser as it is. By this method, accurate analysis is enabled. |
