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Badania prądami wirowymi połączeń spawanych – wpływ doboru warunków i parametrów badania na czułość i wiarygodność metody – przykłady zastosowań

Wocial Adam

Badania Nieniszczące i Diagnostyka

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2019

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nr 4

29--34

EN

The article presents a practical approach in the application of the eddy current method in cases outside the scope and recommendations of EN/ISO 17643: 2015 [1] regarding the testing of eddy currents of welded joints. This standard does not explicitly limit the scope of application to specific materials and welding methods, but gives e.g. recommendations regarding calibration standards, probe construction and test parameters. Such a situation may cause misunderstanding and a number of wrong decisions affecting the result of the examination. The article gives several examples of eddy current testing of welded joints where a completely new approach was required that went far beyond the aforementioned standard, e.g. testing of aluminum welds, duplex steel, metallic coatings, and electron beam welding.

PL

W artykule zaprezentowane jest praktyczne podejście w zastosowaniu metody prądów wirowych w przypadkach wykraczających poza zakres i zalecenia normy EN ISO 17643: 2015[1] dotyczącej badania prądami wirowymi połączeń spawanych. Norma ta nie ogranicza wyraźnie zakresu stosowania do konkretnych materiałów i metod spawania, natomiast podaje np. zalecenia dotyczące wzorców kalibracyjnych, budowy sond i parametrów badania. Sytuacja taka może powodować niezrozumienie i szereg błędnych decyzji wpływających na wynik badania. W artykule podano kilka przykładów badania prądami wirowymi połączeń spawanych, gdzie wymagane było zupełnie nowe podejście wykraczające daleko poza wspomnianą normę jak np. badanie spoin stali duplex, aluminium, badania poprzez powłoki metaliczne czy np. spawanie wiązką elektronów.

2

The role of powder layer thickness on the quality of SLM printed parts

Nguyen Q. B., Luu D. N., Nai S. M. L., Zhu Z., Chen Z., Wei J.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 3

948--955

EN

Achieving good mechanical properties as well as the dimensional accuracy and the smooth surface quality of selective laser melting printed parts with minimal post treatments are essential in additive manufacturing. In the present study, Inconel 718 samples with different powder layer thickness (20, 30, 40 and 50 μm) were additively fabricated using 3D Systems ProX-300 machine. The results reveal that the lower the layer thickness, the denser and good dimensional accuracy were achieved. Marginally higher mechanical properties and microhardness were also obtained at the lower thickness while the failure strain was still high. This can be explained through significant change in the microstructure due to different cooling rate and thermal cycles. In addition, the formation of ɤ′ and ɤ″ intermetallic phases, which were well distributed in the matrix and grain boundaries, during heating/cooling, gave rise in the strengths. Fractography shows the plastic deformation band due to work hardening and the crack initiation sites at sub-micro/micro pores, lack of fusion areas and the boundary of unmelted particles. The study would guide engineers balance their options between the production rate and the building parts’ quality.

3

Development of WC-Inconel composites using selective laser melting

Nguyen Q. B., Zhu Z., Chua B. W., Zhou W., Wei J., Nai S. M. L.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1410--1420

EN

In the present study, selective laser melting (SLM) was used to successfully fabricate Inconel 718–tungsten carbide (WC) composites. The processing parameter optimization results reveal that nearly non-porous composites (99.54%) were achieved with the laser power of 220 W, scanning speed of 850 mm s−1, and the hatch spacing of 150 μm. The microstructural characterization unveils that elongated grain structure in the heat flow direction was observed in the case of pure IN718 while WC particles served as obstacles to hinder the grain growth in the composites. The formation of in situ intermediate layer and the strong interfacial bonding between WC super-hard particles and the matrix acted as load bearing and significantly contribute to the overall properties of composites. Mechanical tests indicate significant improvements of microhardness and tensile strengths, although a drop in strength was observed when the amount of WC reached 15 wt.%. In addition, the thermal experiment shows that the composites are dimensionally stable at higher temperature compared to their monolithic counterpart. The findings suggest that the developed IN718-WC composites can be utilized in many critical engineering applications in nuclear sector.

4

Badania toczenia spiekanych proszkowo materiałów z zastosowaniem oprogramowania Production Module

Matras A., Zębala W.

Zarządzanie Przedsiębiorstwem

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2017

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Vol. 20, nr 1

16--21

EN

This paper proposes a scheme of investigations aimed at stabilizing the value of the components of cutting force along the cutting tool path. The proposed optimization method is based on the modification of the feed rate and calculated components of cutting forces on the basis of the cross-section layer and material model. As part of the study the proposed method was verified. The turning process of the aircraft engine element was analyzed. The stabilization of the cutting force components caused a significant reduction their maximum values.

5

Trials to manufacture and test castings from Inconel alloy

Uhl W., Pirowski Z., Jaśkowiec K.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 3

73--78

EN

The article describes the methods of producing and testing the Inconel 740 nickel alloy in as-cast state. An assumption has been made that the obtained alloy should be characterised by a normative chemical composition and mechanical properties similar to those that are obtained in the process of plastic forming. The alloy was fabricated by conventional process and vacuum metallurgy in the form of pilot castings enabling various types of tests to be carried out. Within the test and investigations programme, moulding materials were chosen, castings were poured and subjected to the process of heat treatment, followed by tests and examinations of alloy properties (mechanical tests, cooling curves). The outcome of the investigations was cast alloy characterised by chemical composition close to the normative one but of the mechanical properties inferior to those obtained by plastic forming.

6

High speed cutting of superalloys

Hoffmeister H. W., Wittmer R., Schnell C.

Journal of Machine Engineering

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2009

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Vol. 9, No. 1

18--28

EN

A possibility to improve the productivity in production industry is the implementation of high speed cutting processes. In particular, the high performance machining of superalloys such as titanium- and nickel-based alloys makes high demands on tools and machines. Therefore, it is important to understand the chip formation mechanisms during high speed cutting. This paper describes the effect of different influential variables including the tool chip angle, cutting velocity, chip thickness and the structure of the superalloys Inconel 718 and TiAl6V4 on chip formation and cutting forces. The experiments were accomplished on a a quick-stop experimental rig, which allows to decelerate the workpiece, even for very high cutting speeds, within a distance which is smaller than the chip thickness. The experimental examinations were completed by temperature measurements. The knowledge of the resulting tool, workpiece and chip temperatures from high performance machining of hard machinable alloys at high cutting speeds contributes to understanding of the different chip formation mechanisms and the influence on tool-life.