The lack of welds should have been obvious in a visual inspection, they said.
Cylindrical fillet-welded joints under tensile and torsion loads are analyzed to investigate the sensitivities of weld geometry-related parameters, such as size of lack of penetration, weld shape and weld root radius, on the fracture response of the joint.
The lack of structural welding defects for this variant was assessed by ultrasonic testing.
The cracking was found to be ammonium nitrate-induced stress corrosion cracking and the failure was attributed to a lack of post-weld stress relieving of the fabricated structures.
Chung et al. [8] analyzed the effects of lack-of-penetration crack size, weld leg size, and main plate thickness on mixed-mode stress intensity factors of load-carrying fillet welded cruciform joints using the finite element method and the least-squares method, and the general formulae of modes I and II stress intensity factors obtained from numerical results were verified by experimental results.
On the other hand, the properties of the TIG joint are affected by the lack of a post-weld heat treatment, which causes the material from the upper part of the weld to be significantly worse than that of the lower region.
Generally, low rotational speeds lead to insufficient flow of material in the weld zone and lack of fusion between the weld and base material.
An investigation of weld quality showed relatively large lack of penetration in the weld root.
For a lap joint with a free transverse (Y direction in this paper) boundary constraint at the main plate, a joint with a smaller size of lack-of-penetration, a reasonably large weld leg and smaller flank angle is recommended to be used in engineering practice, in order to obtain a higher fatigue strength.
It was found that the main cause of line pipe failures at the weld was lack of fusion defects and cracks produced by inadequate welding heat input in electric resistance welds (ERWs).
