Estimation of multi-pass welds deformations with Virtual Weld Bead method

Weld defect formation in rail thermite welds

A previously developed heat transfer model is used to study the influence of welding parameters on weld defect development in thermite welds. Weld defect formation maps are constructed from a series of heat transfer simulations. For the current normal rail thermite welding conditions, it is found that shrinkage cavity formation can be avoided but cold-lap and centre-line defects are likely to o...

Variation of Mechanical Properties in a Multi-pass Weld

As part of a programme investigating the structural integrity of welds, the Digital Image Correlation (DIC) technique was used to obtain the full-field strain distribution during tensile testing of cross-weld specimens cut from a multi-pass girth welded pipe. The displacement maps were analyzed using Matlab scripts to compute local stress-strain variations from which the local proof stress valu...

The Physics of Weld Bead Defects

A Weld Position Recognition Method Based on Directional and Structured Light Information Fusion in Multi-Layer/Multi-Pass Welding

Multi-layer/multi-pass welding (MLMPW) technology is widely used in the energy industry to join thick components. During automatic welding using robots or other actuators, it is very important to recognize the actual weld pass position using visual methods, which can then be used not only to perform reasonable path planning for actuators, but also to correct any deviations between the welding t...

Experimental determination of the annealing effect on critical area of HSLA multi-pass girth weld at natural gas pipelines

Shield metal arc welding on the high strength low alloy steels in pipelines to transport natural gas from Iran is of great importance. In this article the effects of annealing heat treatment on properties of multi pass welding in different situations (6-4:30 , 4:30-3 , 3-1:30 , 1:30-12) with 36 in outside diameter is evaluated by chemical,  metallography, tensile, toughness and hardness. Tensil...