Study of Methods for CTOD Testing of Weldments

Machida, Susumu; Miyata, Takashi; Toyosada, Masahiro; Hagiwara, Yukito

doi:10.1520/stp24094s

Cited by 12 publications

(2 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, this kind of analysis might allow to determine whether the crack grew inter/intragranular, phase or microconstituent [67,73,74]. Regarding the sectioning technique in weldments samples, consult the following references [12,67,72,75,76]. Additional microstructural technique such as electron backscattered diffraction (EBSD) analysis could be used to determine the orientation of the grains where the crack grew [74,[77][78][79], in addition, whether other deformation mechanism was activate such as twinning [80].…”

Section: Fracture Surface Analysismentioning

confidence: 99%

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

Ávila

Lima²,

Ruchert

et al. 2016

Soldag. insp.

View full text Add to dashboard Cite

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.

show abstract

Section: Fracture Surface Analysismentioning

confidence: 99%

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

Ávila

Lima²,

Ruchert

et al. 2016

Soldag. insp.

View full text Add to dashboard Cite

show abstract

“…The cross-sections of the welded joints were polished and etched (3% nital) to reveal the microstructures. 9 Previously performed fracture toughness testing 10,11 showed that in the case of unstable crack propagation, the fracture toughness value depends on the microstructure of the crack tip region. Hence, fracture toughness analysis of unstable crack propagation requires classification of the fracture toughness data relating to the microstructures at the crack tip.…”

Section: Metallographic Investigation Of Microstructuresmentioning

confidence: 99%

Determination of lower bound fracture toughness of a high strength low alloy steel welded joint

Gubeljak¹

2005

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

The use of high strength low alloy steels for high performance structures (e.g. pressure vessels and pipelines) requires high strength consumables to produce an overmatched welded joint. This globally overmatched multipass welded joint contains two significantly different microstructures, as-welded and reheated. In this paper, the influence of weld metal microstructure on fracture behaviour is estimated in comparison with the fracture behaviour of composite microstructures (as-welded and reheated). The lower bound of fracture toughness for different microstructures was evaluated by using the modified Weibull distribution. The results, obtained using specimens with crack front through the thickness, indicated low fracture toughness, caused by strength mismatching interaction along the crack front. In the case of through thickness specimens, at least one local brittle microstructure is incorporated in the process zone at the vicinity of the crack tip. Hence, unstable fracture occurred with small, or without, stable crack propagation. Despite the fact that the differences between the impact toughness of a weld metal and the that of base metal are insignificant, the fracture toughness of a weld metal can be significantly lower.

show abstract

Fracture behaviours of fracture toughness testing specimens with metallurgical heterogeneity along crack front

2000

View full text Add to dashboard Cite

Safe use of welded structures is dependent on fracture mechanics properties of welded joints. In present research, high strength low alloyed HSLA steel in a quenched and tempered condition, corresponding to the grade HT 80, was used. The fluxo cored arc welding process (FCAW), with CO2 as shielding gas, was used and two different tubular wires were selected. The aim of this paper is to analyse fracture behaviour of undermatched welded joints, and also to determine relevant parameters which contribute to higher critical values of fracture toughness. Towards this end three differently undermatched welded joints were analysed using results of testing the composite notched specimens with through thickness crack front positioned partly in the weld metal, partly in heat affected zone (HAZ) and partly in base material (BM).The presence of different microstructures along the pre‐crack fatigue front has an important effect on the critical crack tip opening displacement (CTOD). This value is the relevant parameter for safe service of welded structure. In the case of specimens with through thickness notch partly in the weld metal, partly in the heat affected zone and partly in the base material, i.e. using the composite notched specimen, fracture behaviour strongly depends on a partition of ductile base material, size and distribution of mismatching factor along vicinity of crack front. If local brittle zones occur in the process zone, ductile base metal can not prevent pop‐in instability, but it can reduce it to an insignificant level while the fracture toughness parameter is higher and the weakest link concept can not be applied.

show abstract

Study of Methods for CTOD Testing of Weldments

Cited by 12 publications

References 2 publications

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

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

Determination of lower bound fracture toughness of a high strength low alloy steel welded joint

Fracture behaviours of fracture toughness testing specimens with metallurgical heterogeneity along crack front

Contact Info

Product

Resources

About