STUDIES ON MECHANICAL PROPERTIES OF 19-9 D L

Abstract

Niobium was effective to increase ductility of the short-time tensile test at 700°C in the age-hardened, or "hot cold worked" state. In creep rupture testing above 650°C, Nb was effective to increase ductility, and rupture life. Effect of Nb is distinct at longer time or higher temperature of testing and at "hot cold working" rather than in age-hardened state.
The higher the working temperature of "hot cold working" the lower the strength on short time tensile test, and the shorter the creep rupture time, the more increased ductility in both testing. Reduction of working at "hot cold working" had little effects on the result of the short-time tensile tests, but by increasing the reduction of working, creep rupture time was shortened.
Tensile and yield strength increased by "hot cold working" beyond 700°C and creep rupture test at 600, 650, 700°C, beyond 100h. of testing time were studied in age-hardened state. At 650°C, 100h creep rupture strength was somewhat 13kg/mmmm2 lower than in "hot cold worked" condition, but its difference was reduced in proportion to testing time.