Abstract
To obtain the low cost and high resistant steel for mixture gases in ammonia synthesis, the author studied on the effect of hydrogen and nitrogen at pressure 650atm and temperature 550°C on the same kinds of steel as in the 2nd report. (Lect. Meet. Iron & St. Inst. Japan, Apr. 1951) The author inserted the specimens in catalyst bed for 491 hours, and exposed them to high pressure and temperature mixtures. After exposure, the author tested them by the same method as in the former report. The main results obtained were summarized as follows:
1) In the Casale Plant, attacks of nitrogen were very important as the same degree as in the Claude Plant.
2) Chromium containing steel always had cracks by mixture attacks, but in case chromium content increased as much as 5 percent, the availability of chromium in steel was recognized for the first time.
3) Nickel was the useful alloy element because of its crack-proof properties just like in the previous report.
