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Surfacing 24Cr-5Ni-2.5Mo Duplex Steel Castings by TIG

Kasinska J., Skrzypczyk A., Kalandyk B.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

15--20

EN

This article discusses the influence of Tungsten Inert Gas (TIG) surfacing of duplex cast steel on its hardness and structure. The samples of 24Cr-5Ni-2.5Mo ferritic-austenitic cast steel were subjected to single-overlay processes with the use of solid wire having the chemical composition similar to that of the duplex cast steel. As a result of the surfacing, the welds were obtained that had no welding imperfections with a smooth transition to the base material. In the test without the heat treatment, directly below the fusion line, we observe a ferrite band with a width of approximately 200 μm without visible austenite areas. Some of the samples were then solution treated (1060°C). Both variants, without and after solution heat treatment, were subjected to testing. Significant changes in the microstructure of the joint were observed after the heat treatment process (heat affected zone and weld microstructure changes). In both areas, an increase in the austenite volume fraction after solution heat treatment was observed. Changes in the microhardness of the ferrite in the HAZ area directly below the fusion line were also observed.

2

Zmiany mikrostruktury w połączeniach spawanych różnoimiennych materiałów stosowanych w energetyce

Blicharski M.

Przegląd Spawalnictwa

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2013

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R. 85, nr 3

2-13

PL

W pracy przedstawiono zmiany mikrostruktury w połączeniach spawanych materiałów o różnej strukturze krystalicznej. Opisano materiały stosowane do budowy kotłów energetycznych. Omówiono tworzenie się struktury podczas krzepnięcia stali austenitycznych. Zwracając szczególną uwagę na wpływ składu chemicznego na fazy tworzące się bezpośrednio z cieczy oraz na zmiany w mikrostrukturze podczas chłodzenia z temperatury krzepnięcia do temperatury pokojowej. Przedstawiono ponadto wykresy umożliwiające przewidywanie tworzącej się mikrostruktury w spoinie materiałów różnoimiennych w oparciu o skład chemiczny łączonych stali i zastosowanego spoiwa.

EN

The work deals with microstructure in welded joints of materials with different crystal structures. The materials used for construction of power plant boilers were investigated. The development of microstructure during solidification of austenitic stainless steels was discussed. In particular, an emphasis was put on the influence of chemical composition on phases forming directly form the liquid state and changes in microstructure occurring during cooling from solidification temperature to room temperature. In addition, diagrams allowing for the prediction of microstructure forming in welded joint between dissimilar materials were presented. The prediction was based on the chemical composition of the welded steels and applied filler metal.

3

Wykrywanie niejednorodności materiału i lokalnych zmian mikrostruktury metodą prądów wirowych

Babul T, Jończyk S., Samborski T., Włodarczyk S.

Przegląd Spawalnictwa

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2013

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R. 85, nr 12

25--28

PL

Celem badań było określenie możliwości wykrywania lokalnych różnic we właściwościach części wykonanych ze stali 40HNMA, spowodowanych obróbką cieplną, obróbką powierzchniową oraz miejscowymi przypaleniami szlifierskimi. Zmiany te mają istotny wpływ na trwałość wyrobów, zwłaszcza kół zębatych. Zastosowano układ pomiarowy nowej generacji: Wirotest 302 oraz sondy o zróżnicowanej częstotliwości nominalnej od 250 kHz do 2 MHz. Dokonano oceny wpływu zmian strukturalnych, stanu powierzchni, a także obecności pęknięć na charakterystyki wiroprądowe. Badania potwierdziły także skuteczność wykrywania lokalnych zmian mikrostruktury spowodowanych przypaleniami szlifierskimi. Wyniki badań zweryfikowano przez pomiar mikrotwardości i chropowatości.

EN

Numerical simulations play an increasingly important role in nondestructive testing. They are widely used for the development of testing methods to confirm their effectiveness. Their main purpose is to support the analysis and interpretation of the research results. The paper shows the possibilities of ultrasonic testing modeling on immersion testing of composite test piece example. In the component made of carbon-epoxy composite, intentionally created defects are located. The defects were made by lamination of thin, flat, rectangular teflon inserts of known dimensions. The ultrasonic immersion tests of the component are compared with the results of simulations carried out for the created numerical model. The results showed the high value of the numerical simulation.

4

The influence of Fe content on spreading ability of tungsten heavy alloys matrix on tungsten surface

Kaczorowski M., Skoczylas P., Krzyńska A.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3 spec.

103--106

EN

The results of experimental study of tungsten spreading ability with W-Ni-Co-Fe matrix are presented. The aim of these investigations was to see how Fe concentration in W – Ni – Co matrix influences the wettability of tungsten grains during liquid phase sintering. Four green compact specimens containing 50%W, 10%Co and Ni + Fe = 40% but with different Ni to Fe ratio were prepared. The cylindrical specimen 5mm diameter and 5mm height were put on clean pure tungsten substrate and then 20 minutes heated at 1520ºC in hydrogen atmosphere. After heating the specimens were carefully measured and then the specimens for structure observations were prepared. It was concluded, that increase of Fe content decrease the melting temperature of W – Ni – Co alloy. The melting point decrease caused by Fe content increase substantially the spreading ability of tungsten substrate with W – Ni – Co alloy. Metallography investigations showed some microstructure changes in “reaction zone” identified in tungsten substrate – (WNi40-xCo10Fex) interface. The results of the study confirmed our earlier observations that even relative small Fe addition promotes Weight Heavy Alloys (WHA) liquid phase sintering.