Schemel, J. H.
Chief Metallurgist, AMAX Specialty Metals, Inc., Akron, N.Y.
Pages: 13 Published: Jan 1969
Zirconium and its alloys are both strain-rate sensitive and at times highly anisotropic. This combination of attributes causes difficulty in properly conducting and evaluating tension-test results.
Four factors affecting test results were studied in this investigation: strain rate, specimen geometry, test-specimen linkage, and specimen orientation in large sections.
Strain rate was found to affect yield strength strongly. Only in the case of the ASTM specimens was a plateau found in the yield-strength-strain-rate curve. Other specimens showed a continuing lowering of yield strength with decreasing strain rate even at very low levels of strain rate.
Elongation was found to be very sensitive to both specimen shape and orientation of the specimen in the cross section.
A model of typical specimen support linkage in an elevated temperature test is examined to show how cross-head displacement is related to specimen strain and the resultant variations in strain rate in constant cross-head speed tests.
The results of a round robin sponsored by ASTM Committee B-10 on tension testing of tubing are presented, showing the variation among laboratories doing the testing. Attempts to explain the variation in the light of the data presented in the first part of the paper are not completely adequate but indicate necessary areas for standardization, particularly in specimen-support linkage.
zirconium, tension testing, strain rate, anisotropy
Paper ID: STP43838S