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Locally adapted properties within a machine component offer opportunities to increase the performance of a component by using high strenght materials where they are needed. The economic production of such hybrid components on the other hand represents a major challenge. The new tailored forming process chain, which is developed within the collabora...
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... acoustic horizontal sectional image (C-scan) is calculated by scanning the samples line by line using an XY-scanner to which the ultrasound probe (transducer) is attached. Parameters for ultrasonic microscopy are shown in Table 3. Figure 6 shows SAM images for a typical sample after welding without forming. ...Citations
... Behrens et al. researched the mechanism of pore closure during hot forming of AISI 52100 claddings, performing compression tests on monomaterial and hybrid specimens. Closing the pores to a large extent required a plastic strain in the cladding material of 0.7 [8]. ...
In contrast to conventional components made from a single material, hybrid multi-material components allow the production of load-adapted parts with different materials in different structural and functional areas. Hardenable and forgeable steels with a high carbon content are suitable for increasing fatigue and wear resistance and thus an extension of component life. However, materials with an equivalent carbon content of more than 0.6 are considered difficult to weld due to their tendency to crack. This study investigates the influence of the shielding gas coverage on the laser hot-wire cladding process with high carbon cladding material AISI 52100. For this reason, welding tests were carried out with different parameter combinations in a process chamber flooded with argon. The oxygen content in the chamber was less than 500 ppm during the welding process. The claddings welded in the process chamber are compared to the claddings welded in a previous investigation with a commercial shielding gas nozzle for laser deposition welding with wire. The tests conducted showed reduced pore formation and very little sparking. By using a process chamber, the average degree of dilution was reduced from 16.9% to 8.5% and burn-off of alloying elements was reduced. In most cases, high hardness values of 700 HV0.1 to 850 HV0.1 were achieved. The use of the process chamber demonstrates that the shielding gas coverage and therefore the remaining oxygen content have a high influence on the process stability and seam quality when welding high carbon steel. Such a considerable effect has not yet been observed with other commercially available cladding steels.
... The employment of advanced signal processing algorithms and images allows not only to visualise structural discrepancies (e.g., cracks or voids), but also material properties (Young modulus, Kirchoff modulus, Poisson coefficient) [37]. In Ref. [38], the possibilities of porosity assessment in padding welds made using the plasma powdered arc method are presented. It was found that the use of ultrasonic waves in the range of 30-110 MHz allows the efficient detection of pores. ...
The last two decades have brought stable and impressive development accompanied by the industry acceptance of the use of high energy techniques based on energy obtained from explosive detonation energy. Such manufacturing processes are not only commercially viable, but also allow complex product shapes and unique combinations of metal sheets in terms of materials to be obtained; they enable the creation of composites which cannot be obtained by other conventional methods. Plated sheets are composed of a base material and a thinner plating material layer. An essential aspect in the validation of explosive welding is the quality control of joints made using this technology. The basic control methods are destructive tests – mainly metallographic, which reveal the microstructure at the connection boundary. Non-destructive tests, used in industrial practice, are classical, normalised ultrasonic tests of welding joints, conducted in accordance with ISO 17640:2017 and ISO 11666:2018 standards. Due to the relatively low thickness of the explosion-tested layers (2 mm and 3 mm single layers), which is the object of this study, assessing them using widely available ultrasonic techniques is limited. According to current scientific studies, the application of the scanning acoustic microscopy (SAM) is a prospective non-destructive method allowing for the qualitative and quantitative assessment of the continuity of the metallic connection on the contact surface of two materials. This paper presents the results of research on the quality of clads, welded explosively using a non-destructive research technique, namely SAM, verified with metallographic tests.
