Critical Crack Tip Opening Displacement for X70 and X80 Steels - A Parametric Study

Abstract:

High strength line-pipe steels are widely used in long distance gas pipelines. Fracture toughness is one major parameter in the performance evaluation of these line-pipe steels. For high strength line-pipe steels, critical crack tip opening displacement (CTOD) is one typical quantity for fracture toughness. In this paper, a series of experimental studies were conducted to investigate the influences of steel property and specimen thickness on critical CTOD by three points bending tests for X70 and X80 line-pipe steel. Results showed that the critical CTOD is mainly depended on the plastic crack mouth opening displacement of the specimen. For the same size specimens, the critical CTOD of X80 steel was much less than X70 steel. The specimen thickness had a significant influence on the plastic crack mouth opening displacement. With the decrease of the specimen thickness, the critical CTOD increased.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 719-724
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.719
• Online since: June 2017
• Authors: Xiao Ben Liu*, Qing Quan Duan, Bao Dong Wang, Hong Zhang
• Keywords: Critical Crack Tip Opening Displacement, Experimental Study, Fracture Toughness, High Strength Line-Pipe Steel, Three Point Bending Tests

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