抄録
The author ambitiously deals with various problems in connection with properties, heat-treatment, workmanship and applications of various alloy steels for aircraft structures, and his personal opinion is subjected to the discussion of the members. In Section I, the economical use of alloy steels is first considered and the author believes that alloy steels are very economical for use in the aircraft structure and further development in this line is very important to Japan.
In Section II outlines the properties of alloy steels generally adopted in aircraft construction, in which nickel steels with various nickel contents, nickel-chromium steels of different qualities, nickel-vanadium steels, nickel-molybdenum and nickelchromium-molybdenum steels, chromium-molybdenum steels etc. are referred to.
High nickel-chromium steels or austenitic stainless steels being very important materials for the larger type of airplane, special consideration is given to them in Section III with regard to their mechanical properties and welding practice.
Aircraft structural steels are almost all cold-worked. The effect of cold-working and heat-treatment upon carbon steels has been well covered by many investigators, but the cold-working of alloy steels being of somewhat later practice, the data hitherto published are inadequate. Thereupon, the author collected necessary information so far as is available and discusses in Section IV the effect of such treatments upon cold-worked alloy steels.
Aircraft structural steels are used in different forms such as bars and rods, sheets and strips, tubes, wires and ropes, components and accessories, etc.; each is separately discussed and various suggestions are given in Section V.
The recent trend in the adoption of alloy steels in aircraft structures has developed the fabricated or mass heat-treatment of such structures, particularly in America, to eliminated heat effects due to welding and also to give uniform structural strength. A brief description on such heat-treating installation is given in Section VI for the consideration ot the members.
In conclusion, the author expresses his personal opinion on the aircraft structuralmaterial as follows:-
"He does not herein prophesy that all future aeroplanes should necessarily be made of alloy steels, but he expects the further development of both the steel and duralumin aeroplanes, as these metals have their own advantages and disadvantages. In Japan, however, the development of alloy steel aeroplanes is still in its infancy, but under the present conditions, alloy steel aeroplanes should be fully developed. For the development of civil aviation, the alloy steel structures should be taken into special consideration when constructing passenger-planes, mail and goods transporting aereplanes of large types. Also, for naval and military service, alloy steels should be very widely adopted in large bombers, flying boats, etc.
In view of the present progress in engineering technique, the complication of the treatment and workmanship can not be unconditionally considered as a disadvantage of alloy steels. In the application of any special material for superior products, special care is always necessary. It is a universal fact that superiority is attained when difficulties are overcome.
Wrought iron is easier than mild steel to deal with, but mild steel has replaced.
Mild steel is easier than alloy steels in treatment, but alloy steels in treatment, but alloy steels are now very widely used for all important parts of engineering construction. Therefore, it should not be overlooked that the advancement of engineering is in overcoming difficulties and producing superior products.
High strength material is sensitive and more difficult to deal with, but when such material is fully controlled, superior results are achieved. The success or failure depends entirely upon the zeal and research of the engineers."
