SURVEY OF LOW-ALLOY AIRCRAFT STEELS HEAT TREATED TO HIGH-STRENGTH LEVELS Part 4. High-Strength Steels and Their General Static Properties

摘要

Part 4 presents a general discussion of the factors which determine the selection of high-strength steels and assembles the data available for their static-strength and design characteristics. In addition, the informa¬tion available on the effects of the numerous variables encountered in mak¬ing, shaping and heat treating low-alloy steels and their significance for the strength properties of aircraft parts is discussed.nThe regular strength characteristics of the steels, and especially their tensile strength, yield strength, elongation and reduction of area, re-veal no indication of an embrittlement of steels heat treated to strength values in excess of 200 ksi, in general, and of those tempered at temper-atures between 500 and 750°F, in particular. However, there is some indication that at very low testing temperatures steels heat treated within this tempering range also may exhibit a comparatively low ductility.nThe response of static strength properties to other factors which adversely affect their performance, such as section size of slack quenching, is also limited and the practical significance of such effects is not clarified.