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Showing 1 to 20 of 23 for “"Post-weld"”.
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Influence of post-weld heat treatment (PWHT) on the tensile behaviour of P91 weldments
… applications in power plant is optimised welding and post weld heat treatment (PWHT) which restores homogeneous mechanical properties after welding. Although optimum PWHT is prescribed in standards, deviations in the field practices can potentially lead to accelerated component degradation …
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The effect of post weld heat treatment on the corrosion behaviour of a AA2050T34-FSW
… of a AA2050T34-FSW was examined as a function of post weld heat treatment condition. Immersion tests in 0.1 M Nac1 and G110 intergranular tests were performed and the corrsion morphology and the depth of attacks in the different regions of the weld were investigated using FEG/SEM. Polarisation …
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Evaluation of post-weld heat treatments for corrosion protection in friction stir welded 2024 and 7075 aluminum alloys
… into the corrosion resistance of friction stir welding (FSW) for aerospace structures. Two of the most common aerospace aluminum alloys, 2024 and 7075, were investigated. In the as-welded condition, both alloys were found to be highly susceptible to exfoliation corrosion, and 7075 was found to …
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The application of positron emission particle tracking to study non-metallic inclusions in metal castings
… superalloys. To achieve weight savings, inertia welding is being trialled for turbine discs but current post weld heat treatments reduce fatigue life. In this investigation, a number of novel post weld heat treatments were trialled aimed at improving post weld microstructure and fatigue …
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Microstructure and Hydrogen Induced Failure Mechanisms in Iron-Nickel Weldments
… of specific subsea dissimilar metal Fe-Ni butter welds has illuminated a fundamental lack of understanding of both the microstructure created along the fusion line as well as its impact on the hydrogen susceptibility of these interfaces. In order to remedy this, the present work compares and …
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Mechanical properties of laser welded semi-solid metal cast A356 alloy
… porosity making it difficult to heat treat and weld. Semi solid metal (SSM) forming has the potential to produce near-net-shape components with high integrity. Due to laminar filling characteristics of SSM HPDC, low porosity or porosity free castings can be produced. This offers the opportunity …
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OPISA optoelectronics packaging interfaces for sub-micron alignment
… the laser source with the optical fibre. Laser welding is used because of its inherent attributes of accuracy, strength, cleanliness and minimised heat affected zone and structural changes. Due to the rapid solidification of the welded parts post welding residual stresses occur which can lead to …
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Laser and electron beam treatments for corrosion protection of friction stir welds in aerospace alloys
Friction Stir Welding (FSW) is a suitable technology for aerospace structure development and is a possible replacement for mechanical fastening. To achieve the application of FSW, pre and post-weld treatments are required. A pre-weld treatment of surface preparation was required to ensure a weld …
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Susceptibility of creep aged material to stress relief cracking during repair welding
The repair welding of main steam pipelines, which involves the welding of new material onto service-exposed material, are investigated. This paper investigates the literature and experimental work surrounding this subject. The introduction provides a background to the applicable welding technology. …
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Exothermic flux forge welding of steel tubulars
Welding processes inevitably alter the local microstructure and in turn affect the properties. For many grades of steels that require high strength, ductility, and toughness, it is difficult to maintain this combination of properties after welding. While full part heat treatments can sometimes be …
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Investigation of Residual Stress In Friction Stir Welded Aluminum Alloys
… property development in friction stir welded 6xxx and 7xxx aluminum alloys through empirical observation and numerical modeling with an emphasis on residual stresses induced by processing. Thermal conditions and weld parameters are varied and resulting weld properties are correlated to …
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In Process Measurement of Hydrogen In Welding
… of atomic, or diffusible, hydrogen dissolved in welds on their mechanical properties have been known for over four decades. However, post weld inspection and repair of hydrogen induced cracks in welds remains the only means of correcting the defects produced by excess hydrogen in the arc …
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Abnormal Grain Growth of AA2195 Friction Stir Weld Nugget during Solution Heat Treatment
<p>Friction Stir Welding is a solid-state joining technology increasingly being applied to aluminum and other alloys in the automotive and aerospace industry due to its advantages in microstructure and mechanical properties over conventional welding techniques. To further enhance the mechanical …
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Friction stir welding of high temperature alloys
<p>"Friction stir welding (FSW) of Ti-6Al-4V alloy, nickel-based and iron-based oxide dispersion strengthened (ODS) alloys (MA754 and MA956) has been studied. The main aspects covered include tool evaluation, microstructural evolution, mechanical properties, and correlation between processing, …
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Grain Boundary Character Distribution in the HAZ of Friction Stir-Processed Al 7075 T7
The heat affected zone (HAZ) of friction stir welded Al 7075 T7 shows diminished corrosion resistance properties when compared with the parent material. Corrosion attack in this region of the weld is primarily intergranular and is associated with the presence of precipitate free zones. Current TEM …
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Phase transformations in welded supermartensitic stainless steels
… applications. Although easily joined by arc welding processes, the service life of the supermartensitic welded joint in corrosive environments relies to a large extent on the behaviour of the heat-affected zone (HAZ). The microstructure of the HAZ in these new materials has, until now, …
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Abrasion-corrosion and stress corrosion resistance of a 9Cr-2Ni-0.7Mo steel in simulated mine water
… conditions viz. as-rolled, tempered, welded and post weld heat treated. The material showed an immunity to sec in all the microstructural conditions for tests conducted at open circuit potential. This apparent immunity is attributed to the difficulty in initiating sec by pitting on the …
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Friction stir welding of commercially available superplastic aluminium
A series of Friction Stir Welds (FSW) has been produced in order to optimise tool designs and weld/process variables to minimise flaws in the weld and obtain the best possible microstructure for superplastic Forming (SPF). Therefore the main goal is to produce friction stir welds which do not fail …
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Stress and creep damage evolution in materials for ultra-supercritical power plants
… fatigue. However, experience has shown that the weldments in these steels are particularly prone to premature creep failure, due to a localised form of cracking in the heat-affected zone {HAZl, which is referred to as Type IV cracking. The work presented in this thesis is concerned with the …
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