Manual Welding Process Research Articles

A prototype virtual reality-based demonstrator for immersive and interactive simulation of welding processes

This paper investigates the use of virtual reality (VR)-based methods to support human-integrated simulation for manual welding processes. Within this concept, a prototype demonstrator has been developed, called ‘the virtual welding environment’, which provides functionality for an immersive and interactive process execution within a virtual environment. The simulation features of this environment enable the user to set up, execute and validate the results of a welding process. This environment demonstrates a promising potential for supporting process design and training procedures related to manual welding.

Estimating bead width and depth of penetration during welding by infrared thermal imaging

The key to the success of robotic welding systems lies in the implementation of adaptive/intelligent welding. Adaptive welding enables dynamic altering of the welding parameters to compensate for changing environment. In a manual welding process, the welder ensures the quality of the weld by monitoring and suitably manipulating the process parameters according to the changing environment and based on his knowledge-base and experience. In the case of adaptive welding, sensors play the role of welder. Welding being a thermal processing method, infrared thermal imaging (thermography) using IR sensors have been a natural choice for sensing and weld process monitoring. This paper highlights the estimation of bead width and depth of penetration during Tungsten Inert Gas (TIG) welding using infrared thermal imaging. The results confirm that IR technique is a sensitive and convenient tool ideally suited to monitor the welding process by mapping and analysing the surface temperature distributions. Comparison of various methods to determine the bead-width during the welding process indicates that using the first derivative, it is possible to obtain a better estimate of the bead-width compared to the full width half maximum or point of inflection methods.

A sensing torch for on-line monitoring of the gas tungsten arc welding process of steel pipes

Non-intrusive and real-time monitoring techniques are increasingly required by manufacturing industry in order to detect flaws in arc welding processes. In this work the development of an optical inspection system, for monitoring the manual gas tungsten arc welding (GTAW) process of steel pipes, is described. The arc plasma visible emission produced during the process was acquired and spectroscopically analysed. Measuring the intensities of selected argon emission lines allowed real time calculation and recording of the axial electron temperature of the plasma. Experimental results showed that the temperature signal varies greatly in the case of instabilities of the weld pool that cause weld defects. A suitable algorithm, based on a statistical analysis of the signal, was developed in order to real time flag defective joints. It is shown that several weld defects such as porosity, dropout, lack of fusion, solid inclusions and craters were successfully detected in a production environment. The performances of the optical sensor were compared with the results of state-of-the-art post-weld controls such as x-rays and penetrating dyes, showing good agreement and thus demonstrating the validity of this quality monitoring system.

An investigation of fusion zone microstructures of welded aluminum alloy joints

Fillet weld “T” joints were produced using dissimilar aluminum alloys by a manual arc welding process. In this study, a heat treatable aluminum–magnesium–silicon alloy and a non-heat treatable aluminum–magnesium alloy were joined. The microstructure of the fusion zone was characterized by optical microscopy. Results reveal that the manual welding process produces adequate fusion, while minimizing weld structure defects.

Combining Welding Expert Systems with Welding Databases to Improve Shipbuilding Production

Construction of a large ship requires many thousands of feet of welding. Whenever the welding process can be streamlined or automated, tremendous cost savings can be obtained. The WELDEXCELL system is a WELDing EXpert manufacturing CELL that provides computerized technical support information, off-line weld planning, and an integrated welding robot/welding system/vision system controller. The first of two subsystems, the Welding Job Planner (WJP) accomplishes off-line intelligent weld planning for both automated and manual welding processes. The second subsystem, the Welding Job Controller (WJC) provides a fully integrated hardware control environment with associated software for combined control of a welding robot, welding equipment, and a robotic vision system. In the WELDEXCELL system, a series of expert systems and databases have been combined in a new type of computer software environment called a blackboard. There are as many as 19 separate components of the Welding Job Planner subsystem of WELDEXCELL which fall into five interrelated functional groups. WELDEXCELL will be used by design engineers, welding engineers, mechanical engineers, and nondestructive testing (NDT) engineers for both manual welding and to interface to automated and robotic welding systems and vision systems. WELDEXCELL also includes the control system hardware and software to provide off-line intelligent adaptive control of the welding process itself. The development of WELDEXCELL is a multi-year effort involving a partnership of government, industry, university research, and technology transfer. The project has already generated new concepts with potential for future spin-off benefits. The ultimate payback in productivity will be large for the American welding, fabrication, manufacturing, and construction industries.

Nb添加構造用鋼の研究

A high yield stress structural steel which has good notch toughness even for heavy sections, has beendeveloped by addition of a small amount of niobium to a semi-killed steel.Selection of heating temperature before hot rolling and subsequently the control of the amount ofniobium-precipitates in the steel, were found to be very important to the manufacturing process.The steel thus developed has a yield stress greater than 36kg/mm2, good notch toughness by V-Charpyimpact value of over 3.5kg-m/cm2 at 0°C and high fatigue strength over 30kg/mm2 by repeated bendingtests.The steel has good weldability comparable to conventional manganese-silicon steels with equivalent tensilestrengths, and can be welded either by manual or automatic welding processes.