×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Electron Beam Weld SS to Ta

Electron Beam Weld SS to Ta

Electron Beam Weld SS to Ta

(OP)
I did post in Welding , but here might be better
Im trying to get 316 SS to take or braze or glue to Ta it seems to work in most cases

is there a matl I can use as a filler to enhance the bond


I have used tantalum in the moly to moly bond

and found that was good

RE: Electron Beam Weld SS to Ta

Fusion welding will not work for this dissimilar material combination. Either diffusion bonding or friction welding are options.

RE: Electron Beam Weld SS to Ta

(OP)
Yes , vastly different melting temps

These work in Ultra high vacuum and 1000C

What Im doing is joining SS to tantalum pretty well , It must be a braze

In 20% of parts I get cracking and the SS, just a does not join to the Ta ,

I dont know why

Its not a metallurgy problem , just a how lucky I get trying to seal SS to Ta, not too cool and not too hot

RE: Electron Beam Weld SS to Ta

Quote (NX687)

These work in Ultra high vacuum and 1000C

So what you're saying is you need a brazed joint that can survive at temps above 1000degF? What is the brazing material you are using?

The reason you are getting cracks in your parts is likely due to a 2.5X CTE mismatch between the 316 cres and Ta. One thing you might consider doing to remedy the problem is optimizing the local section thicknesses of the mating parts at the joint so that the strains and stresses in both parts are more balanced both after brazing and during service.

Since you know the dimensions of the mating parts and the material properties of these parts and the brazing material, you should be able to calculate the relative strain in each part resulting from the joint cooling from the brazing temp to room temp. If your calculations show there is high enough stress produced in the 316 cres part from the CTE mismatch to cause failure, then you have a design problem. If not, then you likely have a metallurgical problem causing the cracking.

Good luck.

RE: Electron Beam Weld SS to Ta

(OP)
Tbuelna

Thanks
by CTE do you mean matl expansion difference

You know that SS is joined to Aluminium oxide for high vacuum and up to 250 Centigrade temperature application,
That type of strain relief method would work

In that case a braze matl is used , I wish to join the Ta to SS Directly for a 1000 Centigrade application , no braze matl is allowed

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources