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1

The influence of laser surface alloying on the thermal fatigue resistance of hot work tool steels

Jonda E., Brytan Z., Labisz K., Drygała A.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 3

1309--1314

EN

The paper presents results of the effect of laser surface remelting and alloying by carbides powders of NbC, TaC, TiC, VC and WC on the structure and thermal fatigue resistance of the surface layer of hot work tool steels X40CrMoV5-l and 32CrMoV12-28. The laser surface alloying and remelting treatments was performed using a high power diode laser (HPDL ROFTN SLNAR DL 020). In order to investigate the effect of applied laser treatments and used alloying powders on the microstructure and thermal fatigue resistance of processed surface layer of hot work tool steels, the inicrostructure evaluation by light microscopy, hardness test, and dedicated thermal fatigue resistance test were performed. The best results regarding fatigue cracks inhibition was obtained when the surface of hot work tool steels was alloyed with TiC and VC carbides at the laser beam power of 2.0 and 2.3 kW. The grain refinement effect of laser remelting has a lower impact on the thermal crack inhibition, than a strong strengthening effect of matrix saturation in alloying elements and precipitation of fine carbides in the steel matrix.

2

The Influence of Laser Surface Remelting on the Microstructure of EN AC-48000 Cast Alloy

Piątkowski J., Grabowski A., Czerepak M.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

217--221

EN

Paper present a thermal analysis of laser heating and remelting of EN AC-48000 (EN AC-AlSi12CuNiMg) cast alloy used mainly for casting pistons of internal combustion engines. Laser optics were arranged such that the impingement spot size on the material was a circular with beam radius rb changes from 7 to 1500 μm. The laser surface remelting was performed under argon flow. The resulting temperature distribution, cooling rate distribution, temperature gradients and the depth of remelting are related to the laser power density and scanning velocity. The formation of microstructure during solidification after laser surface remelting of tested alloy was explained. Laser treatment of alloy tests were perform by changing the three parameters: the power of the laser beam, radius and crystallization rate. The laser surface remelting needs the selection such selection of the parameters, which leads to a significant disintegration of the structure. This method is able to increase surface hardness, for example in layered castings used for pistons in automotive engines.

3

Modification of Ti-6Al-4V titanium alloy microstructure as result of laser carbonizing.

Sieniawski J., Filip R., Pleszakow E., Mrówka G.

Inżynieria Materiałowa

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2001

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R. XXII, nr 5

819-822

EN

The laser surface remelting of Ti-6Al-4V titanium alloy without coat was carried out in order to determinate its microstructure. Laser alloying was performed on samples, coated by graphite powders in order to form titanium carbides as a consequence of laser pulsed irradiation. Alloyed layers containing TiC phase in ductile martensitic matrix exhibit high microhardness (about 6 GPa), excellent bonding with the substrate and are free of cracks.

PL

Przeprowadzono laserowe przetopienie powierzchni stopu tytanu Ti-6Al-4V przy użyciu lasera impulsowego. Stosowano próbki z pokryciem grafitowym oraz bez pokrycia. Obserwowano zmiany mikrostruktury stopu w warstwie przetopienia i strefie wpływu ciepła. Stwierdzono wzrost mikrotwardości (do około 6 GPa) modyfikowanych laserowo warstw wierzchnich.

4

Corrosion characteristics of laser surface remelted Al-Si alloy.

Serbiński W., Olive J.M., Frayret J.P.

Inżynieria Materiałowa

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2001

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R. XXII, nr 5

812-815

EN

The effects of laser surface remelting at cryogenic conditions on the local chemical compositions, microstructure and corrosion characteristics of AlSi13Mg1CuNi alloy have been presented. The beneficial effect of laser treatment on the corrosion behaviour of the cast aluminium alloy in 0.01 M H2SO4 solution was observed.

PL

Przedstawiono wpływ laserowego przetapiania w warunkach kriogenicznych na lokalny skład chemiczny, mikrostrukturę i charakterystyki korozyjne stopu AlSi13Mg1CuNi. Uzyskano pozytywny wpływ obróbki laserowej na zachowanie korozyjne odlewniczego stopu aluminium w roztworze 0.01 M H2SO4.