Fatigue crack propagation in welded joints X70

Abstract

Structural failure assessment approaches take into account local parameters, specimen geometry, loading and material. In the case of welded joints, in addition to these parameters, consideration must be given to the effect of the heterogeneity of properties due to welding. The objective of our work is to study the fatigue crack propagation of welded joint in API X70 pipeline steel. This experimental study focused on welded joints in the different parts, base metal, weld metal and heat affected zone. The concepts of fracture mechanics are used to analyze the harmfulness of defects in welded joints and the main part of fatigue life falls on the crack propagation. The results obtained show that the fatigue crack propagation rate of cracks in the heat affected zone is delayed compared to the other zones. The effect of the microstructure and the quality of submerged arc welding of the studied X70 steel are significant. Tensile tests, hardness and measurement of energetically parameters complemented this work.

Influence of themo-mechanical treatments and microstructural state on the fatigue behaviour of a weald seam: case of API X60 steel

“…The slope m is increased and is comparable to the slope obtained in the HAZ. Other authors have drawn the same conclusions on X70 steel [23][24][25].…”

Regression Modeling and Process Analysis of Resistance Spot Welding on Dissimilar Steel Sheets

“…For example, there are 3000 to 12000 spot welds in a car [1,2]. The majority of the research investigations in spot welding has been carried out on the joining of homogeneous materials [3][4][5][6]. Currently, research in different industries is directed towards the reduction of CO 2 emissions.…”

A Simple and Efficient eight node Finite Element for Multilayer Sandwich Composite Plates Bending Behavior Analysis

“…Barut et al [11] analyzed a thick sandwich plate by third and second order theories in which the in-plane and the transverse displacements show cubic and quadratic variations respectively through the thickness of the plate. Other analytical and experimental works can be found for the sandwich plate and shell analysis: Noor et al [12], Kant et Swaminathan [13], Mantari et al [14], Grover et al [15], Kanematsu et al [16], Torabizadeh and Fereidoon, [17], M. Michele et al [18], Deliou Adel [19]. However, analytical methods are only suitable for specific simple boundary conditions and geometries.…”