Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 13, 2020 - September 16, 2020
Tensile tests of premium connection for Oil Country Tubular Goods (OCTGs) were conducted in order to study the effect of thread crest width on the ductile failure mode. As a result, it is found that, whereas a connection with a large thread crest width (1.864 mm ) was fractured with a crack penetrating in the radial direction of the pipe body, connections with small thread widths (1.573 mm , 1.283 mm ) were fractured with a crack penetrating in the longitudinal direction of the mating thread. When a tensile load was applied, as female thread crests at the end of mating went over the male thread crests sequentially, the end of mating could shift toward the pipe end side. Consequently, the ductile failure mode would be changed depending on the difference between the tensile strength of the pipe body at the end of mating and the shear strength of the mating thread.
