Austenite formation and its decomposition control the final microstructure and performance of steel welds. This paper presents an in-situ characterization of austenite formation and its decomposition in both the fusion zone (FZ) and heat-affected zone (HAZ) of an Fe-C-Al-Mn steel using time-resolved X-ray diffraction (TRXRD) with synchrotron radiation. Measurement of X-ray diffraction spectra a...

Friction Stir Welding (FSW) is a relatively new welding technique where metals are joined through mechanical stirring. Due to its numerous advantages over older welding methods, it has been implemented in an increasing number of industries. However, there are remaining challenges to be overcome in FSW. One of the most serious is its reliance on accurate weld parameters. Additionally, faults or ...

The extruded AZ61A magnesium alloy plates of 6 mm thickness were butt welded using friction stir welding (FSW) process. The corrosion behavior of the welds was evaluated by conducting immersion test in NaCl solution at different pH value, immersion time and chloride ion concentrations. An empirical relationship was established incorporating pH value, immersion time and chloride ion concentratio...

Hydrogen enrichment induced by pipeline welding residual stress is a key issue affecting the safe service of hydrogen pipelines. In order to explore influence on diffusion and effect heat treatment, an X80 model with six-layer girth weld was established using ABAQUS software, coupling analysis temperature field, carried out. The distribution in area local inclusion analyzed, relationship betwee...

The effect of microstructural variations on the tensile and fracture toughness properties of Alloy 718 welds is reviewed. The microstructural parameters surveyed include heat treatment, longterm thermal aging and neutron irradiation. The two heat treatments that were characterized include the conventional heat treatment, per ASTM B637, and a modified heat treatment designed to improve the tough...

Ultrasonic testing of austenitic stainless steel welds is often difficult because the ultrasonic beam is subjected to many perturbations : deviation, partition, distortions and sometimes ghost echoes. These perturbations are due to the anisotropic and heterogeneous metallurgical structure of the welds. We are carrying out a research program in order to evaluate the influence of the main paramet...

The effective assessment of the integrity of welds is a complicated NDE problem that continues to be a challenge. To be able to completely characterize a weld, detailed knowledge of its tensile strength, ductility, hardness, microstructure, macrostructure, and chemical composition is needed. NDE techniques which can provide information on any of these features are extremely important. In this p...

DISCLAIMER: Everything that follows is of a preliminary nature. We give a new invariant for finitely generated groups, called the girth. Several results which indicate that the girth of a group might possibly be a quasi-isometry invariant are proved. We also compute the girth in several instances and speculate on the relation of girth to the growth of groups.

a set $wsubseteq v(g)$ is called a resolving set for $g$, if for each two distinct vertices $u,vin v(g)$ there exists $win w$ such that $d(u,w)neq d(v,w)$, where $d(x,y)$ is the distance between the vertices $x$ and $y$. the minimum cardinality of a resolving set for $g$ is called the metric dimension of $g$, and denoted by $dim(g)$. in this paper, it is proved that in a connected graph $...