Journal ArticleDOI
Fracture toughness analysis in transition temperature region of API X70 pipeline steels
TLDR
In this paper, the analysis of fracture toughness in the transition temperature region of API X70 pipeline steels according to ASTM E1921 standard test method was concerned with the application of a 3-point bend test of precracked Charpy V-notch specimens.Abstract:
This study is concerned with the analysis of fracture toughness in the transition temperature region of API X70 pipeline steels according to ASTM E1921 standard test method. Two kinds of steels were fabricated by varying finish rolling temperatures, and their microstructures and mechanical properties were examined. Elastic–plastic cleavage fracture toughness, KJc was determined by three-point bend tests of precracked Charpy V-notch specimens, and then the measured KJc values were interpreted by the three-parameter Weibull distribution. Fractographic observation indicated that the critical distance from a precrack tip to a cleavage initiation site linearly increased with increasing critical J value. Effects of martensite–austenite constituent (MA) and effective grain size on fracture toughness in the transition region were analyzed from the standpoint of cleavage crack initiation and propagation. The higher volume fraction of MA led to the lower resistance to cleavage crack initiation, and the larger effective grain size led to the lower resistance to cleavage crack propagation. Thus, the steel rolled in the two-phase region had the higher fracture toughness in the transition region and the lower reference temperature and energy transition temperature than the steel rolled in the single-phase region because of the lower volume fraction of MA and the smaller effective grain size.read more
Citations
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Effect of zirconium addition on the impact toughness of the heat affected zone in a high strength low alloy pipeline steel
TL;DR: In this paper, the effect of zirconium additions on the impact toughness of the heat affected zone in a high strength low alloy pipeline steel was studied, and the corresponding toughening mechanism examined when the welding was conducted with large heat input.
Journal ArticleDOI
New insights into intragranular ferrite in a low-carbon low-alloy steel
TL;DR: In this article, single and multiple nucleation events on non-metallic inclusions have been observed, leading to the intragranular formation of ferrite as a function of transformation temperature.
Journal ArticleDOI
Effects of microstructure on crack resistance and low-temperature toughness of ultra-low carbon high strength steel
TL;DR: The effects of microstructure on crack resistance and toughening mechanism of an ultra-low carbon steel were investigated in detail in this article, where the microstructures were controlled via thermal-mechanical control processing (TMCP) and heat-treatments.
Journal ArticleDOI
Impact toughness of friction stir processed low carbon steel used in shipbuilding
TL;DR: In this article, the effect of single pass friction stir processing (FSP) on the impact toughness of a low carbon steel mainly used in shipbuilding was investigated via Charpy impact test at different temperatures, and the results were correlated with the radical microstructural alterations during processing.
Journal ArticleDOI
On the relation of microstructure and impact toughness characteristics of DSAW steel of grade API X70
TL;DR: In this article, the impact properties of double submerged arc-welded line pipe steel of grade API X70 (70ksi yield strength) were investigated, and different experimental examinations including chemical analysis, microstructural investigation, microhardness, tensile and Charpy tests and standard fractography were carried out on different zones of test material.
References
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Journal ArticleDOI
Finite deformation analysis of crack-tip opening in elastic-plastic materials and implications for fracture
TL;DR: In this article, a finite element method was used to analyze the deformation field around smoothly-blunting crack tips in both non-hardening and hardening elastic-plastic materials, under contained plane-strain yielding and subject to mode I opening loads.
Journal ArticleDOI
Relationships between the J-integral and the crack opening displacement for stationary and extending cracks
TL;DR: In this paper, the relationship between the J-integral and the crack opening displacement δt is obtained by exploiting the dominance of the Hutchinson-Rice-Rosengren singularity in the crack-tip region.
Journal ArticleDOI
The scatter in KIC-results
TL;DR: In this article, two different approaches, one based on a microstructural statistical model and an other based on the Weibull distribution are applied to evaluate the theoretical scatter in KIC-results.
Book
Thermomechanical Processing of High-Strength Low-Alloy Steels
TL;DR: In this article, the authors describe a thermomechanical processing of high-strength low-alloy steels using high strength low alloy (HLSL) steels.
Journal ArticleDOI
Analysis of different acicular ferrite microstructures in low-carbon steels by electron backscattered diffraction. Study of their toughness behavior
TL;DR: In this paper, the morphology of the obtained intragranular microstructures has been found to depend on the steel composition, the prior austenite grain size, and the density of particles able to promote intra-granular nucleation.