Lack Of Sidewall Fusion Razor Blades
Lack Of Sidewall Fusion Treatment
Welding Defects - Classification, Causes And Remedies ...
Lack Of Sidewall Fusion Image

Where is Cracking?

In welds both the lack of fusion which is a structural defect and the lack of fusion in which the metal joint is interrupted by voids and non-metallic inclusions may be found. The pure lack of fusion can be detected only by the visual inspection during welding. The other types of lack of fusion may be detected by ultrasonic testing methods.

Cracking can be anywhere, but it needs some specific boundary conditions to initiate. Therefore, similar to other typical pipeline anomalies, a fundamental question is the time dependency of crack-like anomalies. For cracking, a time dependency is hard to observe. Therefore, cracks in pipelines can be categorized into environmentally assisted active cracking and mill-related or dormant planar anomalies.
Cracking can be found at any location of the pipeline, be it in the pipe body or in the welded areas. But pipeline cracks are always detected perpendicular to the main local stress direction of the pipe material. A pressurized pipeline experiences so-called hoop stress, which creates an environment for axial cracking. Likewise, an axial load on the pipeline supports the occurrence of circumferential cracking.
Another factor is the exposure of the pipeline surface. A corrosive environment or other impact on the surface of the pipeline – mechanical damage, for example – also support the initiation of cracking due to micro-embrittlement. Finally, the pipeline material and its mechanical properties are contributing, as well. Higher strength steels will be more susceptible to environmentally assisted cracking mechanisms associated with hydrogen embrittlement eg SSCC, or hydrogen embrittlement due to CP overprotection. The presence of hard spots can also contribute to higher susceptibility to environmentally assisted cracking due to local residual stresses.

Lack Of Sidewall Fusion Razor Blades

Demonstrating the capability of radiography is important for justifying the integrity of certain nuclear power plant components. In particular, Magnox Electric plc has been investigating the reliability of the radiography performed on Magnox steel reactor pressure vessel welds during construction. This work has concentrated on planar defects of structurally significant size.

Lack Of Sidewall Fusion Treatment

This paper describes an extensive series of experimental studies of radiographic capability, for material thicknesses in the range 50-114 mm. These studies have been supported by surveys of the relevant parameters of real metallurgical defects to confirm the realism of the defects used. The results have been interpreted using a well-established, albeit simplified, theoretical model of the radiographic process, but further work on a more comprehensive theoretical model is in progress to provide more precise comparisons of theoretical and experimental results.

1) Excess Weld Metal Height 7) Poor Toe Blend. 6)Porosity2) Lack of Sidewall Fusion 5) Root Penetration3) Lack of Root Fusion4) Slag inclusion & Lack of inter-run fusion 47.
Lack of sidewall fusion 22.5 73 -22 3 Longitudinal HAZ hydrogen crack 33.0 123 + 17 4 Lack of sidewall fusion 17.5 83 -22 B 5: Lack of sidewall fusion 33.5: 82 + 23: 6 Solidification crack 59.5 92 +4: 7 Longitudinal HAZ hydrogen crack 50.0 132 - 19: 8 Lack of sidewall fusion 40.0 71 +22: 9 Solidification crack 41.0 85 -6: 10 Longitudinal HAZ.
Planar defects are very often weld related and are defects such as lack of fusion and cracks, that is, they lie in one plane (two dimensional) as compared to the less serious volumetric defects which are three dimensional (slag etc).
Sidewall lack of fusion occurs when the weld metal does not fuse in to the side of the weld groove, leaving a smooth, planar discontinuity along the edge of the weld groove. Doubling is a phenomenon that can occur when.

Considerable care has been taken to produce planar defects which realistically simulate those which might conceivably occur during welding of thick-section ferritic steel pressure vessels. One key feature is the orientation of the defect relative to the radiographic beam, and this can be controlled reasonably precisely when inducing defects in test specimens. Another crucial parameter for radiographic detection is the crack face separation (gape), which can only be measured by sectioning.

Welding Defects - Classification, Causes And Remedies ...

The results demonstrate the capability of radiography to detect a wide range of manufacturing defects of a size which might be of structural concern, even when they are substantially misoriented to the beam. Once sectioning has been completed (currently underway), the results will provide quantitative evidence of the combinations of defect size, tightness and orientation which can be detected.

Lack Of Sidewall Fusion Image

The practical assessments of radiographic capability have been performed by TWI. Funding for this has been provided by the Industry Management Committee (IMC) which is supported by the nuclear licensees in Britain.