MEASUREMENT OF CTOA OF PIPE STEELS USING MDCB AND DWTT SPECIMENS

Published

September 27, 2010

Author(s)

Christopher N. McCowan, S. Xu, W. R. Tyson, R. Eagleson, Elizabeth S. Drexler, J. D. McColskey, Philippe P. Darcis

Abstract

Two types of specimen for crack tip opening angle (CTOA)measurement have been investigated for pipeline applications,i.e., the modified double cantilever beam (MDCB) (at NIST)and the drop-weight tear test (DWTT) specimen (at CANMET). Results of effects of specimen types, thicknesses and loading rates on CTOA are summarized and discussed. The main observations include: (i) For both MDCB and DWTT specimens tested at quasi-static loading rate, crack front tunnelling(i.e., with a deep triangular crack-tip shape) was present in high-strength steels; (ii) For DWTT specimens, CTOA values measured optically at the surface were signifi cantly higher than those from the simplifi ed single-specimen method (S-SSM)and measured at mid-thickness [on sections cut using electric discharge machining (EDM)]; and (iii) CTOA values from surface measurement of MDCB specimens were comparable to those derived from S-SSM of DWTT specimens, but the surface values of DWTT were higher than those of MDCB specimens.

Proceedings Title

Proceedings of the 8th International Pipeline Conference IPC2010
September 27-October 1, 2010, Calgary, Alberta, Canada

Conference Dates

September 27-October 1, 2010

Conference Location

Calgary

Pub Type

Conferences

Download Paper

Local Download

Keywords

CTOA, MDCB, DWTT, ductile fracture, fracture toughness, pipe steel, test method

Citation

McCowan, C. , Xu, S. , Tyson, W. , Eagleson, R. , Drexler, E. , McColskey, J. and Darcis, P. (2010), MEASUREMENT OF CTOA OF PIPE STEELS USING MDCB AND DWTT SPECIMENS, Proceedings of the 8th International Pipeline Conference IPC2010 September 27-October 1, 2010, Calgary, Alberta, Canada, Calgary, -1, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=905067 (Accessed October 7, 2025)