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Influence of the base metal grain size and heat input on decarburization in single pass SAW and multi pass SMAW welded joints of dissimilar ferritic steels

Nimko M. O., Skulskyi V. Yu.

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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Vol. 119, nr 1

14--26

EN

Purpose This paper aims to assess a separate influence of heat input and base metal grain size on microstructural evolution in the weld adjacent zone of bainitic steels with 1.5…2.0% Cr, welded or overlayed with consumables with 9% Cr after post-weld heat treatment. Design/methodology/approach Analysis of the width of decarburised layer on microphotographs of welded or overlayed specimens after tempering at 750°C. Specimens were made by using different welding approaches: single-pass welding, multi-pass welding and overlaying. Findings It is shown that with an increase of the heat input energy, the width of the resulting decarbonised layer decreases linearly; the increase of the base metal grain size leads to a decrease in the layer width after tempering at 750°C. The microhardness testing showed the average hardness in the decarburised layer of 15Kh2M2FBS steel was 161 HV0.1 (minimum – 154 HV0.1), while the average hardness in the rest of the heat-affected zone was 192 HV0.1. Research limitations/implications Future research may include comparing the creep rupture strength of the weldments made with different welding parameters or base metal grain size to assess the influence of these factors on creep rupture strength. Practical implications Results permit to achieve minimisation of the rate of carbon diffusion in the weld-adjacent area of the heat-affected zone by means of variation of welded parameters and base metal grain size. Originality/value An influence of high-diffusivity paths (grain boundaries) on carbon diffusion in the heat-affected zone of dissimilar weldments was confirmed experimentally; the correlation between base metal grain size/welding parameters and the rate of the diffusion during high-temperature exposure was found.

2

Influence of welding parameters on decarburization in heat affected zone of dissimilar weldments after post weld heat treatment

Nimko M.O.

Archives of Materials Science and Engineering

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2021

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Vol. 112, nr 1

23--31

EN

Purpose: This paper aims to assess an influence of thermal welding parameters on microstructural evolution in the weld adjacent zone of P91 steel, overlayed by austenitic consumables, after post weld heat treatment. Design/methodology/approach: Analysis of the width of decarburized layer on microphotographs of overlayed specimens after tempering 750°C, 7 and 18 hours. Specimens were made by using different heat input and preheating temperature parameters. Findings: It is shown that with increase of the heat input energy, the width of the resulting decarbonized layer decreases linearly; the effect of heating temperature on the layer width is parabolic with a minimum at a temperature of ~195°C. Research limitations/implications: Future research may include comparison of the creep rupture strength of the weldments, made with different welding parameters, to assess the influence of kinetics of decarburization and variation of the parameters on creep rupture strength. Practical implications: Results permit to achieve minimization of rate of carbon diffusion in the weld adjacent zone of the HAZ by means of variation of welded parameters. Originality/value: Experimentally was confirmed a role of high-diffusivity paths (grain boundaries) on carbon diffusion in the HAZ of dissimilar weldments; found correlation between welding parameters and the rate of the diffusion during high temperature exposure.

3

Comparison of CVD graphene grown on copper foil and PVD copper

Pasternak I., Grodecki K., Piątkowska A., Ciuk T., Caban P., Strupiński W.

Materiały Elektroniczne

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2013

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T. 41, nr 2

26--33

EN

Graphene synthesis by the CVD method performed on the surface of copper is one of the most promising techniques for producing graphene for low cost and large scale applications. Currently, the most commonly used Cu substrate for graphene growth is foil, however, there is still a need to find new substrates and improve the quality of graphene layers. Sputtered Cu films on insulating substrates are considered as an alternative. Here we show the properties of graphene grown by the CVD method on thin copper foil and PVD copper films on Si/SiO2 substrates. We compare data on the properties of graphene films transferred from different copper substrates onto SiO2/Si substrates. We note that graphene grown on sputtered Cu films creates a multilayer form on the boundaries which can be identified on micro-Raman maps and in SEM images.

PL

Wytwarzanie grafenu metodą CVD na podłożach miedzianych jest jedną z najbardziej perspektywicznych metod otrzymywania grafenu ze względu na niski koszt podłoża oraz szerokie możliwości zastosowania w przemyśle. Obecnie najczęściej stosowanym do wzrostu grafenu podłożem miedzianym jest folia, jednakże ciągle istnieje potrzeba znalezienia nowego podłoża tak by poprawić jakość warstw grafenu. Jako alternatywę rozważa się cienkie warstwy miedzi wytwarzane metodami PVD osadzane na nieprzewodzącym podłożu. W niniejszym artykule przedstawiamy własności grafenu wytwarzanego metodą CVD na cienkiej folii miedzianej oraz na warstwach miedzi osadzonych na Si/SiO2. Porównujemy także wyniki otrzymane dla przeniesionych warstw grafenu z obu rodzajów próbek.

4

Wpływ intensywnych odkształceń plastycznych na strukturę aluminium i jego stopów

Richert M., Leszczyńska-Madej B., Richert J., Boczkal S.

Rudy i Metale Nieżelazne

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2010

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R. 55, nr 5

284-291

PL

W artykule przestawiono zmiany struktury Al99,5, Al99,992 i Al99,999 oraz stopów AlMg5 i AlCu4Zr powstające w wyniku wywierania intensywnych odkształceń plastycznych przy użyciu metody Cyklicznego Wyciskania Spęczającego (CWS). Stwierdzono, że wywieranie dużych odkształceń prowadzi w aluminium i jego stopach do powstania licznych pasm i mikropasm ścinania. Przecinając granice ziaren mikropasma zmieniają kształt granic. Wewnątrz ziaren powstają mikropasma i podziarna, zwykle ograniczone w wymiarach do przestrzeni pomiędzy przecinających się mikropasmami. Charakterystyczną cechą mikrostruktury po intensywnym odkształceniu plastycznym jest obecność licznych granic o dużej dezorientacji.

EN

The microstructure changes of Al99.5, Al99.992, Al99.999 and AlMg5, AlCu4Zr alloys affected by severe plastic deformations exerted by Cyclic Extrusion Compression (CEC) has been presented in the work. It has been found that large deformation leads in aluminum and its alloys to multiplication of numerous shear bands and micro-shear bands. Bands crossing grain boundaries change its geometry. Inside grains the microbands and subgrains have been formed usually restricted to the distances between the crossing bands. The distinct feature of microstructure after the severe deformations is the existence of numerous grains with large misorientation.

5

Influence of point defects and grains size on the course of reversible martensite transformation in melt spun ribbons of the copper based alloys

Kostrubiec B., Wiśniewski R., Rasek J.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 16, nr 1-2

30--34

EN

Purpose: In the paper Cu-Al-Ni-(Mn, Ti) alloys exhibiting the shape memory effect were studied. For the investigated alloys the characteristic temperatures of the reversible martensitic transformation, the influence of grains size and vacancy concentration on the course of the transformation were examined. Design/methodology/approach: Using the resistometric method it was shown that the characteristic temperatures of the reversible martensite transformation strongly depend on the grains size. Findings: For Cu-Al-Ni alloy the activation energy of migration of monovacancies and the pre-exponential factor of the Arrhenius equation were determined as [wzór], respectively. Practical implications: The paper shows that the investigated alloys can be used as important functional or the so-called intelligent materials (actuators, sensors). Originality/value: The parameters of the electronic structure - i.e. the coefficient of conduction electron scattering at grain boundaries, the mean free path, the coefficient of reflection of conduction electrons at grain boundaries, and the electrical resistivity for Cu-Al-Ni in the martensite and parent phase were determined.