Abstract
In generally, it is usual used austenitic stainless steel in boiler tubes and pipes. Recently, another stainless steel, ferrite steel is often used at boiler plants but it is thought the setup place of that's steel is appriate in the sea or on the ground as endurance of erosion and corrosion and so on. Detail scription is described by each specialized researchers and studys in laboratories. In this time, I absent from presentation of the paper or thesis, described personal opinion as the end-user.
