Conventionally, the quality of the weld is ascertained only after the welding has been completed through the use of NDT techniques. A lot of time, material and manpower is wasted before one comes to know about the soundness of the weld. These limitations can be overcome if the weld is continuously monitored in real time for the assessment of defects using appropriate NDE sensors. This paper hig...

Ultrasonic inspection of dissimilar welds is still a challenge due to the different acoustic impedances across the interfaces between parent metals, welded, butter or cladded regions. Typically parent metals are fine grained carbon/ferritic/20MnMoNi55 steel, which show isotropic character. Whereas weld/butter/cladded metals are INCONEL/ austenitic steel, which exhibit anisotropic character, att...

PWR reactor vessel (RV) head has a number of penetration nozzles, including nozzles with thermal sleeve for control rod drive mechanisms (CRDM) and without thermal sleeve. These nozzles are typically made of nickel-based Alloy 600 or 690 and welded to the inside of the RPV head. Cracking has been reported in Alloy 600 nozzles and the J-weld regions. These nozzles are normally inspected by eddy ...

Welding is a reliable and effective metal fabrication process which is widely used in industries. High heating at a one location during welding and further rapid cooling generates residual stress and distortion in the weld and base metal. In last few decades various research efforts have been directed towards the control of welding process parameter aiming at reducing residual stress and distor...

Recent development in image processing allows us to apply it in different domains. Radiography image of weld joint is one area where image processing techniques can be applied. It can be used to identify the quality of the weld joint. For this the image has to be stored and processed later in the labs. In order to optimize the use of disk space compression is required. The aim of this study is ...

The continuous tandem cold rolling of metal strip is a highly nonlinear multi-variable complex process the control of which presents additional challenges over those encountered in the control of stand-alone tandem cold rolling. These challenges arise during the passage of the weld, which joins the head of the next strip to the tail of the present strip to maintain the continuity of rolling. Th...

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...

Recently developed optical inspection tools provide images from the inside of natural gas pipelines to monitor pipeline integrity. The vast amounts of data generated prohibits human inspection of the resulting images. We designed an image processing and classification method to identify abnormal events. Non-overlapping image blocks are classified into twelve categories: normal, black line, grin...

A method of joining metals with semi-solid slurries is presented. Experiments have been carried out using a model alloy of Sn-Pb to demonstrate the concept. The advantages of this process are a controlled microstructure of the weld, lower post-welding stresses and a small heat affected zone. Tensile tests have been performed, showing a weld strength comparable to bulk material strength. Key fac...

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...