Gaps at part interfaces pose a major challenge for laser transmission welding (LTW) of thermoplastics due to the reliance on contact conduction between the absorptive and transmissive parts. In industrial applications, gaps between parts can occur for a variety of tolerance and process control reasons. Previous experimental and modeling work in LTW has focused on gap-free joints, with little at...

In the current study, a thermal model was used to investigate the effects of welding parameters on the distribution of temperature in wide gap aluminothermic rail welds. To solve the governing thermal equation, SUTCAST, a finite difference program (FDM) was employed while different aspects such as phase change and convective heat transfer in weld pool were taken into account in the numerical so...

The wide-gap aluminothermic rail welds with root opening of 50-70 mm were produced using plain carbon steel rail and non-alloy aluminothermic charge. Mechanical properties and micro-structure of the weld metal and HAZ as well as the impact energy and the fracture toughness of the welds were investigated. The yield and tensile strength of wide-gap welds were about 98% and 95% of the base metal, ...

Both laser-arc hybrid welding and narrow gap welding have potential for the fabrication of thick sections, but their combination has been seldom studied. In this research, 40 mm thick mild steel was welded by narrow gap laser-arc hybrid welding. A weld with smooth layer transition, free of visible defects, was obtained by nine passes at a 6 mm width narrow gap. The lower part of the weld has th...

in this paper, two api x70 steel pipes (with spiral seam weld) of 56 inch outside diameter and 0.780 inch wall thickness were girth welded first. next, hole drilling tests were conducted for strain measurement on the surfaces of the pipes. the values of residual stresses on the internal and external surfaces of the pipe were determined, from strain data using astm 837 standard. the experimental...

This thesis presents a collection of theoretical and experimental investigations into various geometrical aspects of hybrid laser-MIG welding. The work is divided up into four parts; 1. A review of the hybrid laser-MIG welding technique with brief summaries of the three papers which make up the remainder of the thesis. 2. A paper entitled “Fundamental analysis of hybrid laser-MIG welding”. This...

Rail thermite (or Thermit) welding is a valuable welding technology for the railway industry because of its simplicity, portability, and economy. Using the finite-element method, a heat transfer analysis is conducted in this study. Only the heat transfer by conduction was simulated explicitly in the model, the other thermally significant phenomena were included through the boundary and initial ...

In this study, the tensile strength, impact strength, and the hardness of the weld are determined. A criterion is proposed for describing the effect of residual stress on the weld mechanical properties. Dimensionless parameters such as Rya (the average of residual stress over the material yield strength), Rym (the maximum residual stress over the material yield strength), ...

TIG welding is an arc-welding process that produces coalescence of metals by heating them with an arc between a non-consumable tungsten electrode and the base metal 1 . Many delicate components in aircraft and nuclear reactors are TIG welded due to its reliability. Basically, TIG weld quality is strongly characterized by the weld pool geometry as shown in Figure 1. This is because the weld pool...

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...