Welding method choice
Welding method choice
(OP)
Are there any instructions how to choose welding technology (MIG, TIG, EBW, etc.) based on the relevant application?
I am designing a structure that should be dynamically (vibrations) tested soon, and I originally instructed to use TIG method.
The workshop prefers to use MIG welding.
I wonder what should I do? I originally chose TIG since I read it's the best quality welding.
But now after being asked for changing it to MIG I really want to deeply understand what the consequences might be.
When learning welding in the university we dealt with the size of the welding by dedicated calculations, but I couldn't find any considerations regarding which technology is best suited for the entire different applications.
I am designing a structure that should be dynamically (vibrations) tested soon, and I originally instructed to use TIG method.
The workshop prefers to use MIG welding.
I wonder what should I do? I originally chose TIG since I read it's the best quality welding.
But now after being asked for changing it to MIG I really want to deeply understand what the consequences might be.
When learning welding in the university we dealt with the size of the welding by dedicated calculations, but I couldn't find any considerations regarding which technology is best suited for the entire different applications.
RE: Welding method choice
RE: Welding method choice
The applied loads are accelerations and vibrations.
I attached a schematic picture of the part, its bodies and materials.
RE: Welding method choice
RE: Welding method choice
On miscellaneous parts-welding in general, just asking the welder in question "Hey, what's the best way to do this?" can be informative. Shops can vary in the equipment and skills available, and if there's a faster easier way, that'd be the preference unless there is some good reason to do otherwise.
RE: Welding method choice
Just to make sure - when (simple) calculations are done the penetration depth isn't taken into account, right? I will be grateful to know why in this case a full penetration is a key factor to safe design.
Thanks!
RE: Welding method choice
https://www.lincolnelectric.com/en-gb/support/proc...
RE: Welding method choice
RE: Welding method choice
General practise in drafting is to call up the part that you will accept from the vendor. You don't care how they make it. Call up the length of your weld, its size and penetration. If you want heat treatment, call up the hardness. Don't tell your welder how to do his job.
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JHG
RE: Welding method choice
They just have to be sized etc appropriately for the job. And of course properly welded.
For fatigue resistance the details of the toes of the welds can sometimes make or break the design at surprisingly low stress levels, even overwhelming fancy filler metal choices.
TIG "washing" or grinding and peening the weld toes where needed can be powerful fatigue fighters.
With no load info and support details, by inspection the design could be robust or just as easily wimpy and flexible subjecting all the components shown and un-shown to stresses way beyond any simplified analysis.
RE: Welding method choice
RE: Welding method choice
Then you just need to think about most of the geometric stuff, like how large of a throat you need, any shape requirements on the bead (convex, concave, etc), whether you can allow backing strips behind it, finishing techniques (peening, stress relieving, heat treating), etc etc. But you won't need to think about the technique that actually deposits the metal onto the part.
RE: Welding method choice
RE: Welding method choice
We first tries to find the best parameters for the welding process, so we welded 2 simple samples (simplified geometry with same materials and thicknesses) and cut them so we will be able to examine the depth of penetration.
We actually tried 4 set of parameters and here are the results.