JIc Determination of Five Cast Steels at Room Temperature and −45°C (−50°F)

Abstract

JIc tests using the multiple specimen procedure described in ASTM standard E813 were conducted at room temperature and −45°C (−50°F) with five common carbon or low alloy cast steels, viz., 0030, 0050A, C-Mn, Mn-Mo, and 8630. Specimen thickness was 25.4 mm (1 in.). Valid JIc values were obtained with four of the cast steels at room temperature and only two of the cast steels at −45°C (−50°F). Only Jcl (Jcleavage ) values were obtained with the four other tests due to unstable brittle or cleavage fracture. Valid JIc values were obtained if the test temperature was above the mid-point temperature of the Charpy V notch energy transition region as measured along the temperature axis. Conservative estimates of KIc were calculated from JIc test results and a preliminary empirical equation involving KIc and Sy at room temperature and upper shelf CVN energy was suggested for cast steels. Room temperature JIc values were higher for the three tempered martensitic cast steels than for the two ferritic-pearlitic cast steels.