STUDIES ON MECHANICAL PROPERTIES AT ELEVATED TEMPERATURE OF Timken 16-25-6(III)

Abstract

Authors studied the effect of reduction of the hot-cold working on creep rupture properties at 650°C, 31·5kg/mm2. The results are as follows:
11.1t was observed by macroetching the transverse section of the specimen that hot-cold-worked specimen was not worked uniformly in its section. When it is finished in square section by hot-cold working, severely stressed portion disperses in diagonal line. When it is finished in round section, severely stressed portion concentrates in the center. The reduction of working of the specimen differs fairly with the location in the square section from which specimen is taken. So, a round bar is used to study the effects of the reduction of hot-cold working.
2. Creep resistance increases by the reduction of working to the critical value, but exceeding this limit it decreases. This critical value of the reduction of working is dependent on the working temperature and the pre-treatment of hot-cold woking.
3. Three specimens were picked from the diferent locations in a section of 40mm square bar which was hot-cold worked. Creep characteristics of the specimens differs owing to their location where they are taken.