高壓筒材料の研究(I)

Abstract

The foundamental problems of steels for high pressure vessel used in ammonia synthesis can be devided as follws: 1) Mechanical strength at high pressure and temprature2) Chemical attack by high pressure and temperature gases In high pressure vessels and covers, 1) is the most important, while in internal parts, catalyst tubes, heatexchange tubes etc., 2) is the most important roblem.As one way of studying about the chemical vessels, we tested the changes of the high pressure vessels, made at the Muroran plant of Japan Steel Werks, Ltd., and used for about twenty years. The authors took specimens from these materials and tested the changes of their chemical composition, micro structure, mechanical properties and gas adsorption.As results of the tests, it was found that the high pressure vessels, made from NiCr steel and used for about twenty years, could stand the use of longer period. Nevertheless, the upper cover used for the same period and under the same condition was attacked by gases under high pressure and at high temperatures.