Ceramics to steel 1

[FC2008]

Hi,
I need to insert a ceramic (Alumina, Zirconia) inside of a steel housing. The piece is cylindrical.

I have done some reading about brazing, and this is an option, but I am wondering if there are other ways of accomplishing this?

Thank you.

 

[unclesyd]

You need to comeback with a little more information about what you are trying to accomplish.

What sizes are you talking about?

what specific materials are you using?

What temperature will the part see?
With CS I'm assuming under 750F.

Depending on this information there may be several approaches to bonding/attaching the ceramic to the steel. There are numerous adhesives both organic and inorganic that could possibly fill your needs.

 

[tomwalz]

Brazing works
pressure fit - possible but tricky

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[arunmrao]

How about forming a thread on the ceramic insert. If the size is large you can consider similar techniques as used in pin insulators.

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

 

[FC2008]

I apologize for my poor explanation.

The temperature will be in the range of -40 - 180degC.

The material of the steel housing could either be Duplex or Inconel, maybe 625...

Let's say that the Zirconia or Alumina part is cylindrical shape with diameter of about 40mm, and that the steel housing is 60mm in diameter.
Just think of the housing as a piece of tube with the Zirconia cylindre inserted.

How would you go about brazing this part? Insert Zirconia cylindre into tube and just braze the thing?
I have never done brazing.

Thank you.

 

[moltenmetal]

What are you brazing to what in this case? No braze that I know of will adhere to these refractory materials...

The trick with ceramics is to keep them continuously in compression. Consider heating the outer sheath metal and shrinking it onto the ceramic core.

 

[arto]

could you glue it in with this stuff?

http://www.cotronics.com/vo/cotr/ca_1.htm

{like high temp ceramic loctite)

 

[tomwalz]

It can be brazed.

Brazing will have the added advantage of providing cushioning between the steel and the ceramic as the part shrinks in the cold.

We do this regularly see:

http://www.carbideprocessors.com/brazing_services.htm

There are braze alloys that work but they require exotic metals and special atmospheres.

Tom


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[arunmrao]

Just a thought,we do not know the quantities to be brazed. If the quantity is small,it will not interest a commercial brazing shop.Hence, one can try the threaded insert concept,though the brazing option in my opinion is a good choice technically.

Chocolates,men,coffee: are somethings liked better rich!!
(noticed in a coffee shop)

 

[unclesyd]

Aside the large gap i don't think that you will have any problem going the way suggested by tomwalz or arto. The only problem might be the low temperature.
If this is a one off I definately would look to someone well versed in the art if you indeed need it to be brazed.

Why the high Nickle Alloys?

What type of load is going to be placed on the ceramic part.

 

[TVP45]

You might also look at flamespraying a metal coating onto the ceramic. I have done that in the past; it's a little tricky but gives a nice surface. Ceramic on metal is straightforward, but metal on ceramic can crack unless you find a shop with experience. There's still the question of brazing, but a decent process control should take care of that.

 

[tomwalz]

Our minimum quantity is one.

Tom

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[FC2008]

First of all, thank you all for great replies.
I should have mentioned that this system will be exposed to rather high pressures, up to 15ksi. But I do not see this as the biggest issue, since the brazing will not have to carry any load.

What are you brazing to what in this case? No braze that I know of will adhere to these refractory materials...

The trick with ceramics is to keep them continuously in compression. Consider heating the outer sheath metal and shrinking it onto the ceramic core.

I might be able to use Duplex instead of Inconel. The reason for these materials is that there might be a lot of H2S present. And in addition they love these materials in the oil business..

About ceramics being continuously under compression, would you mind explaining why this is so?

could you glue it in with this stuff?

http://www.cotronics.com/vo/cotr/ca_1.htm

{like high temp ceramic loctite)

I will definitely look into it. Thanks.

We do this regularly see:

http://www.carbideprocessors.com/brazing_services.htm

Thank you for the link, very informative site. Impressive.

You might also look at flamespraying a metal coating onto the ceramic.

Is this done to get a better brazing, or is there some other reason?

Again, thank you very much for your time.

 

[moltenmetal]

tomwalz: what you guys do is COOL! A star for the cool factor alone! I knew you could braze tungsten carbide but that's simply because you're brazing to the metallic binder, but my hat's off to a guy who can braze to alumina!

 

[tomwalz]

Motlenmetal,

Thank you for the kind words. Pretty good way to start the day.

I think you can also braze to the tungsten. We don’t see any difference in bond strength between lower binder materials and high binder materials. However our only real test is that they all work so the testing is not at all exhaustive in this area. Also a properly prepared piece of tungsten carbide has a tremendous surface area which aids in the physical joining and may compensate for weaker intermetallic joining.

We actually braze to the titanium in selected Aluminas using standard Bag braze alloys using a water based metallizing (plating) process. For straight Alumina we use special alloys and vacuum.

Tom


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.