Guide for Recommended Practices to Perform Crack Tip Opening Displacement Tests in High Strength Low Alloy Steels

Abstract

Fracture mechanics approach is important for all mechanical and civil projects that might involve cracks in metallic materials, and especially for those using welding as a structural joining process. This methodology can enhance not only the design but also the service life of the structures being constructed. This paper includes detailed consideration of several practical issues related to the experimental procedures to assess the fracture toughness in high strength low alloy steels (HSLA) using the crack tip opening displacement (CTOD) parameter, specifically pipeline steels for oil and gas transportation. These considerations are important for engineers who are new in the field, or for those looking for guidelines performing different procedures during the experimentation, which usually are difficult to understand from the conventional standards. We discuss on topics including geometry selection, number of replicate tests, fatigue precracking, test procedure selection and realization, reports of results and other aspects.

Influence of hydrogen on the microstructure and fracture toughness of friction stir welded plates of API 5L X80 pipeline steel

“…After finishing the CTOD test, the samples were separated in two halves to conduct the fracture surface analyses, as indicated elsewhere [38,42]. Figure 4 shows fracture surfaces of samples with highest and lowest toughness values from each one of the assessed conditions.…”

Multivariate Analysis to Relate CTOD Values with Material Properties in Steel Welded Joints for the Offshore Wind Power Industry

“…All 72 CTOD tests were done according to ASTM E1290-08e1c (2008) [12] with standard specimens (single-edge notched bend SE(B) specimen with square B × B cross-section) and the recommended notch [43]. The apparatus used was an oleo-hydraulic dynamic machine (model UFIB-200E-MD5W) configured for a 3-point bending setup and using clip-gauges as the crack growth measuring system.…”