Arc welding

About: Arc welding is a research topic. Over the lifetime, 25393 publications have been published within this topic receiving 168182 citations.

Multimaterial car body design: challenge for welding and joining

Abstract: High safety and low weight are requested for modern automobiles. Both demands are met best by tailored application of different materials. Multimaterial car body design is a challenge for joining and welding.

Material properties of CMT—metal additive manufactured duplex stainless steel blade-like geometries

Abstract: Impeller blades are often individual and complex-shaped components made of challenging metals. As the manufacturing of such blades is highly sophisticated, only a few companies worldwide possess the necessary processing knowledge and that is why long production times have to be accepted by customers. To overcome this economic disadvantage, manufacturing technologies are permanent under supervision and it seems that metal additive manufacturing could thereby play an important role in future. In this paper, wire arc additive manufacturing (WAAM) based on gas metal arc welding (GMAW) is considered. Shape-giving GMAW is well known in industrial manufacturing, but its application is limited due to restrictions by the welding process itself: For thinner wall thicknesses, a significant reduction of the weld process energy is required which increases the risk of process instabilities and spatter formation. Extensive welding process-related efforts have been undertaken to overcome this fact and a new GMAW process, called CMT (Cold Metal Transfer) was introduced. CMT is based on a high-frequency forward and backward movement of the welding wire electrode and provides an almost spatter-free and absolute precise, periodic detachment of accurately defined droplets from the filler wire at very low process energies. In combination with an accurate robotic movement of the CMT welding torch, geometries with minimum thicknesses in the range of 2–4 mm can be build up layer by layer. Additionally, a broad range of different, well established and third party-approved GMAW filler metals for joining is available. In this work, an impeller blade-like geometry out of duplex stainless steel has been manufactured by CMT using a filler wire type G 22 9 3 N L. The investigations have shown that the achieved surface roughness is comparable to sand casting and the microstructure is without any evidence for porosity and lack of fusion. Furthermore, an austenite/δ-ferrite weld microstructure with partly preferred grain orientations and a δ-ferrite content of around 30FN exists. The measured mechanical properties, especially strength and toughness, are comparable to data provided by the filler metal data sheet.

Ultrasonic sensing of weld pool penetration

Abstract: This paper reports how the geometry of the sidewall as it is penetrated by the weld pool during gas metal arc welding (GMAW) can be detected by high-frequency sound waves. The penetration geometry is detected using a piezoelectric transducer, operating in the pulse-echo mode, to generate shear sound waves that travel through the base metal to the weld region. The received echoes contain information that can be related to the sidewall penetration and thus to the quality of the weld. Different geometries can be discriminated using expert system methods, thus providing the potential of sending information on sidewall penetration to a closed-loop welding system for real-time feedback control to assure adequate sidewall penetration.