Small punch test method assessment for the determination of the residual creep life of service exposed components: outcomes from an interlaboratory exercise

The main aim of the experimental work described is the comparison of the re sults of the conventional creep tests with those of small punch creep tests , i.e. of miniaturized disc bending tests performed on 14 MoV 6 3 and X20 C rMoV 12 1 steels, respectively, in different laboratories. It turned out th at, in the case of small punch tests, too, the time to fracture can be calc ulated using an equation of the Dorn type, in which load is substituted for stress. However, the creep activation energies calculated according to thi s equation are somewhat lower than those relating to the conventional uniax ial creep tests. A comparison of the results of the tests carried out in di fferent laboratories showed that the repeatability of small punch tests car ried out within an individual test laboratory or using the same item of tes ting equipment is very good and perfectly comparable with the repeatability of results using conventional creep tests. (C) 1999 Elsevier Science S.A. All rights reserved.