Abstract
A fracture toughness test system of a turret disc type at cryogenic temperatures was designed and constructed in order to save the testing time and liquid helium consumption for measurement. It includes a computer system for data acquisition and real time analysis using the single specimen unloading method, It enabled us to carry out successive five JIC tests within eight hours including the time for setting and precooling. A necessary amount of liquid helium was about forty liters for five tests.
A 22Mn-13Cr-5 Ni steel was tested at liquid helium temperature on trial and the obtained data were studied and compared with those reported and those obtained from an ordinary multispecimen method. These results showed a good performance of the new test system.
