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DUWELTOOL

DUWELTOOL – General information

This web-based tool is intended as a support in welding duplex stainless steels and to facilitate qualification work. This is done by giving an indication if the ferrite/austenite balance complies with different welding standards and if the risk for precipitation of sigma phase is high or low for a selected combination of: grade of duplex stainless steel, material thickness, filler metal, type of joint, welding process and heat input. The tool is however not intended to replace any tests required for qualification. It must be noted that in simulation models there are simplifications made that will affect output accuracy. The deviation between simulated and measured ferrite/austenite levels for tested single pass welds were around or less than 5% while deviation for tested multi pass were around or less than 10%. This is in the same order as deviations in measured ferrite content. The simulated values from the tool can however not guarantee any level of accuracy.

The tool includes some possibility to vary the heat input by varying the welding current, voltage or welding speed with scroll bars. There is however no limitations or built-in relation between the variables regarding weld quality. For instance, the current level can be set at an unrealistic high level for thin sheets that would result in burn through, the voltage is (in real welding) not independent of current, etc. The number of layers in multi-pass welding is not shown because it also depends on dimensions and type of filler metal etc. and is, for simplicity reasons, not requested as a user input. Specific welding parameters settings, used in tests closest to selected, is shown in PDFs.

In many cases, single pass is selectable for thicker materials but then refers to a specific pass (typically the root pass).

The tool also includes general information for welding different grades of duplex stainless steels (before, during and after welding).

A summary of relevant standards and limits for ferrite/austenite, intermetallic phases and suitable corrosion tests are included, the tool also where possible does a check for the respective weld test if the austenite/ferrite levels are within the range, if it is there is a check mark and if it is outside there is a minus sign. If the standards have not been checked the whole row has minus signs.

Companies and research organisations that participated in the development of the tool are: Outokumpu, voestalpine Böhler Nordic, Sandvik Materials Technology, Forsmark, ITW welding (Elga), Thermo-Calc, Svetskommissionen, Jernkontoret, University West and Swerim.

The project has been completed within the strategic innovation program “Metalliska Material” with funding from Vinnova, Formas and Energimyndigheten.

DUWELTOOL