Continuous Cooling Transformation Diagrams of 2.25Cr-1Mo-0.25V Submerged-Arc Weld Metal and Base Metal
| Autor: | Ronald Schnitzer, Hannah Schönmaier, Bernd Loder, Thomas Fischer, Martin Schmitz-Niederau, Ronny Krein, Fred Grimm |
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| Rok vydání: | 2020 |
| Předmět: |
lcsh:TN1-997
Heat-affected zone Materials science Bainite 2.25Cr-1Mo-0.25V base metal 02 engineering and technology Welding Continuous cooling transformation 01 natural sciences law.invention law Ferrite (iron) 2.25Cr-1Mo-0.25V weld metal 0103 physical sciences General Materials Science Composite material dilatometer measurement lcsh:Mining engineering. Metallurgy 010302 applied physics ferrite phase fraction Metals and Alloys 021001 nanoscience & nanotechnology hardness Martensite CCT diagram Arc welding Dilatometer 0210 nano-technology |
| Zdroj: | Metals, Vol 10, Iss 1055, p 1055 (2020) Metals Volume 10 Issue 8 |
| ISSN: | 2075-4701 |
| DOI: | 10.3390/met10081055 |
| Popis: | The transformation behavior and microstructural evolution during continuous cooling within the heat affected zone between the weld beads of a 2.25Cr-1Mo-0.25V all-weld metal and the corresponding 2.25Cr-1Mo-0.25V base metal were investigated by means of dilatometer measurements, optical and scanning electron microscopy. Furthermore, macro-hardness measurements were conducted and the ferrite phase fraction was analyzed from optical microscopic images using an imaging processing program. Thereupon a continuous cooling transformation (CCT) diagram for the 2.25Cr-1Mo-0.25V base metal and three welding CCT diagrams with different peak temperatures were constructed to realistically simulate the temperature profile of the different regions within the heat affected zones between the weld beads of the multi-layer weld metal. The microstructural constituents which were observed depending on the peak temperature and cooling parameters are low quantities of martensite, high quantities of bainite and in particular lower bainite, coalesced bainite and upper bainite as well as ferrite for the welding CCT diagrams. Regarding the base metal CCT diagram, all dilatometer specimens exhibited a fully bainitic microstructure consisting of lower bainite, coalesced bainite and upper bainite. Only the slowest cooling rate with a cooling parameter of 50 s caused a ferritic transformation. Nevertheless, it has to be emphasized that the distinction between martensite and bainite and the various kinds of bainite was only possible at higher magnification using scanning electron microscopy. |
| Databáze: | OpenAIRE |
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