Abstract
This paper reviews corrosion and its prevention of condenser tubes with the special references to our experiences and researches on copper alloy condenser tubes. In the first part, the research activities which has resulted in a successful development of condenser tubes are briefly summarized and the background of the necessity for further researches and developments in condenser tubes is described. In the second part, after a brief introduction to engineering copper alloys for condenser tubes, some metallurgical factors, such as composition and heat treatment are discussed in detail. Practical and/or trial applications of stainless steel condenser tubes in U. S., U. K. and Japan are introduced. In the third part, several important corrosion phenomena are described as follows based on our experiences and researches. Statistical survey on malignant impingement attack of aluminium brass tubes reveals that the attack is closely related to the precipitation of MnO2 rich film onto the tube surface, which is caused by chlorination of sea water contaminated with manganese. Three modes of relationship between sand erosion and sand contents are demonstrated in connection with the film formation and the abrasive action of sands to the film. Successful data of application of AP bronze condenser tubes in polluted sea water are shown. Importance of protective initial film formation is stressed, especially for aluminium brass tubes used in polluted sea water. In the fourth part, the statistical data of the leakage troubles of condenser tubes in Japan are presented together with those in U. S., which reveals the prominent improvement of service data of Japan in these few years. In the fifth part, our experiences on the galvanic corrosion of Naval brass plates caused by coupling with titanium tubes and hydrogen absorption of titanium tubes due to cathodic protection of Naval brass plates are described. As a result, it is suggested that not only the solution of present-day problems but also future advances in materials development will be possible through a better understanding of the film formed on the tube surface.
