Welding stainless steel to titanium 2

[180994]

Dear Expert,

I need some advise.
Is there have any possibility to weld stainless steel plate (SUS304) to titanium pipe (TP340) by gtaw process?
If so, please advise me the suitable filler rod for this welding.

 

[moltenmetal]

No.

 

[dik]

Can you use 'explosive' welding? Anyone answer?

Dik

 

[EdStainless]

In theory there are braze fillers to do this, but I have never seen it done in an industrial setting.
Buy some explosively bonded plate strips, weld the 304L side to the plate and the Ti side to your pipe.
This is how Al superstructure is welded to steel ships.

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P.E. Metallurgy, Plymouth Tube

 

[gtaw]

While not directly involved, I was told of a fossil fuel power plant that attempted to line their smoke stack with titanium welded to stainless steel blocks that were in turn welded to the carbon steel stack liner. The workers told me there were 4 x 8 foot sheets of titanium shooting out of the stack when they first fired up the boilers!There were sheets of titanium falling from the heavens onto buildings, cars, and people running helter skelter.

Best regards - Al

 

[EdStainless]

If you try to do it directly you form intermetallics that are very brittle, zero joint strength.

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P.E. Metallurgy, Plymouth Tube

 

[dik]

EdStainless: does that include using explosive welding, too? I'm ignorant of this type of attachment, but have seen it used for attaching stainless to carbon steel.

Dik

 

[SwinnyGG]

Explosively welded plates don't form the intermetallics Ed is talking about, because there is no melting of the materials.

If you haven't been exposed to it before, explosive welding of plates is a terribly interesting topic to read up on.

 

[dik]

thanks... only exposed briefly about 20 years back...

Dik

 

[btrueblood]

Depending on the shape, the explosive bonding process is more versatile than some other methods.

https://en.wikipedia.org/wiki/Explosion_welding

These guys near me do it a lot:

http://www.highenergymetals.com/

But there are other methods:

A shop I worked for used to weld titanium-to-stainless adapters onto stainless propellant valve inlets for rocket thrusters, so that the spacecraft fitters could weld on their titanium lines. These adapters were made by friction welding, essentially ramming the two tube stubs together, one held stationary and the other spinning in a lathe, and then trimming them up after. We ran very long term tests over many years confirming that the welded adapters were as corrosion resistant (passive to hydrazine fuels) as their parent materials.

https://en.wikipedia.org/wiki/Friction_welding

Magnetic pulse welding is supposed to be capable of bonding dissimilar materials also.

https://en.wikipedia.org/wiki/Magnetic_pulse_welding

Friction stir welding has also apparently been used for dissimilar materials (aluminum and galvanized steel) in some automotive applications, and there is a lot of research over the past ten years or more on the subject.

 

[dik]

Thanks btb...

Dik

 

[SwinnyGG]

I can speak directly to FSJ of dissimilar metals- it's not on every single car out there but it's becoming more common by the minute.

 

[EdStainless]

I would think that you could go to DMC and buy SS to Ti transition strips, they are not uncommon.

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P.E. Metallurgy, Plymouth Tube

 

[tbuelna]

The fab shop welders I used to work with would look you straight in the eye and say, "Sure it can be done. You just need a special filler wire that is titanium on one side and 304 stainless on the other side.".

All kidding aside, there are solid state processes like diffusion bonding that can produce sound joints between dissimilar metals like titanium and 304 stainless. Unfortunately, diffusion bonding requires specialized equipment (like a HIP chamber) and very careful processing to produce good results. The size of the weldment will also be limited since most HIP chambers are fairly small. If you really need to make the final connection by GTAW, you might consider making a short diffusion bonded Ti/304 adapter that can be GTAW welded between the stainless plate and titanium pipe.

Here's a technical reference on the subject.

https://www.ijerst.com/view.php?iid=237