Can Titanium be bonded, glued, brazed, soldered or welded to steel? 3

[DasKleineWunder]

Titanium sheets are going to be riveted to a rectangular steel tube frame.

Can Titanium sheets also be bonded, glued, brazed, soldered or welded to steel to add SOME additional strength to the strength from the rivets?

i.e. Titanium is said not to be weldable to steel.
Can it be done to create just some additional strength?
I mean even if the welds are fragile they still provide some extra strength.

 

[DasKleineWunder]

Oops I forgot to mention that it is chrome plated steel.

 

[moltenmetal]

Bonded? Glued? Yes. Brazed? Dunno- maybe- there are brazing experts here who would be able to tell you for sure, what alloy and flux materials are required and braze conditions too, but I doubt a simple torch braze is going to work. Welded? No, because the welds will crack immediately upon solidification adding zero strength, and it wouldn't be an option for your chrome plated material anyway if the chrome plating is there for aesthetic reasons.

 

[kingnero]

Most adhesives will work.
When in doubt, ask a sales rep from 3M (Henkel, LocTite) or something like Bison (MS-polymere) to get their opinion.

Welding, as said, won't work. About Brazing: I have no idea, but titanium is very rapidly fouled (with no gaseous protection at elevated temperatures) so I wouldn't count too much on it.

 

[MintJulep]

Chrome plating is not particularly easy to bond to. Probably difficult to braze also.

Even if you could, the strength would be limited to the bond strength of the plating. And while chrome plating's bond strength to steel can be quite high if done correctly.....

 

[SnTMan]

Roll bond, explosion bond, but not likely to hollow sections.

Regards,

Mike

 

[TVP]

There will be a huge hassle for not much improvement if you intend to bond to polished, Cr plated steel. I would not even bother with this.

 

[XL83NL]

Titanium can be welded to steel, by means of explosionwelding. This process shows to provide good results and is especially suited for plate to plate welding (cladding).

Not sure if explosionwelding is regulated in America but it has had some extensive research and application in europe.

 

[Duwe6]

" if explosionwelding is regulated in America "

Regulated, but available.

 

[EdStainless]

Both surfaces (Ti and Cr) will require some surface prep before using an adhesive.
The 3M boys can tell you all about it.
My guess is that there is a special primer for each of them.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[chicopee]

What type of rivets are we talking about? In reference to moltenmetal's response, I think that the chrome plating is more so for corrosion protection than aesthetic reason. I personally would forget the rivets if they are pop rivets, carefully grind the chromium layer where contact is to be made and try out silver solder.

 

[MikeHalloran]

Uh, how about more rivets?


Mike Halloran
Pembroke Pines, FL, USA

 

[racookpe1978]

Aaaaahhhhhh!

I feel like time I open a thread, I need to ask more questions. Regardless, here goes.

Do you need "just strength" to hold the two pieces /three/four/five/fifty parts together, or do you need to prevent motion and leakage (like a tank or pressure vessel or airplane pressurized cabinet, but one that "can leak a little" during use without causing a failure of the system?)

Thermal stress and movement, or simple static pressure? If any pressure at all? Just assembly and simple stress, or will be accelerated and bounced around like a truck or container or shipping vehicle?

Corrosive liquids present? Exotic gasses or unusual temperature changes likely?

Simple mechanical joint required? Like a car or truck body, but one that is only mechanical, not highly stressed?

Good looks important, or not critical? If so, then add bolts!

How many joints and what shape of joints? Is automated assembly of many thousand important, or will you doing piece-part assembly of only a few items by hand?

Both sides of the joint accessible during assembly and operation, or only one side, or neither side? Can the glued joint be "pushed together" adequately to make up the jopint as the resin/epoxy/superglue sets?

 

[tbuelna]

A well designed and applied adhesive bond between a titanium sheet panel and a rectangular steel tube surface might actually be much stronger than a riveted joint, unless lots of rivets are used. You might want to analyze the joint based on the adhesive bond capability, and consider the rivets as a back-up to the adhesive bond.

 

[tomwalz]

You can braze Titanium.

You need to remove the oxide and then plate to prevent re-oxidation.

We did research on this maybe 15 years ago and published it. Nobody seemed to care much. Our conclusion was that plating titanium for brazing was pretty much solving a problem no one had. We were electroplating with cobalt.

Here is another take on the issue.

Plating Clinic in Product Finishing

For more plating items go to ...

http://www.pfonline,com/plate/clinics.html

ARTHUR S, KUSHNER

Kushner Electroplating School, Sunnyvale, CA
platingclinic@pfonline.com

Electroless Nickel on Titanium Revisited
One of our readers had a suggestion for getting a stronger bond between electroless nickel and the titanium substrate. The suggestion is to add a bake step after the deposition of the electroless nickel. The original question and answer is repeated below with the bake step added.

Q. How can we deposit electroless nickel on titanium parts?

A. The key to getting a good adhesive layer of electroless nickel on titanium is proper
preparation of the titanium substrate. In the book, Electroless Nickel Plating, Wolfgang
Riedel, ASM International,

http://www.asm-intl.org,

the following procedure is suggested:
1. Vapor degrease
2. Blast using 220 mesh alumina at 4 bar
3. Rinse thoroughly
4. Etch using 400 g/L HN03 + 5 g/ L HF for 5 minutes
5. Rinse thoroughly
6. Activate using a Wood's nickel strike
7. Rinse thoroughly
8. Electroless nickel plate
9. Bake at 750°F for 30-60 minutes
(added step)

The important thing to remember is that titanium forms a rather tenacious oxide on the
surface almost instantaneously when exposed to the atmosphere. Hence, the steps in the
above procedure must be performed rapidly


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[blakmax]

The etch process above will give you good initial strength but if you want the bond to be durable (last a long time) I suggest that you look at using a process which provides resistance to hydration. Adhesive bonds to any metal are susceptible to formation of hydrated oxides and moisture absorbed from the atmosphere by the adhesive (being a polar molecule water is readily absorbed)will hydrate the oxide layer leading to dissociation of the chemical bonds at the interface, leading to disbonding. In my experience etching alone will not provide resistance to hydration.

I suggest you look at using a silane coupling agent because these form strong covalent bonds at the interface which are resistant to hydration, and provided you select a silane which is compatible with your adhesive the bond will be durable. We have had excellent performance of bonds to steel and titanium using a solvent degrease, grit blast and then application of DOW Z6040 1% silane in distilled water, allowed to stand for one hour before application. Dry at 220F for an hour then bond (or apply a primer such as BR127). Or you could buy a kit called AC130 (goggle it) which contains a few more adhesion promoting agents and works well. and is compatible with epoxy adhesives. As Thomas Walz says, speed is the essence. As soon as you grit blast blow the dust off and apply the coupling agent. Don't wait.

The same process will probably work on the steel as well.

If you want some tips on joint design and processes, try

http://www.tc.faa.gov/its/worldpac/techrpt/artn0657.pdf

Blakmax
Adhesion Associates Pty. Ltd.

 

[tomwalz]

Dear blakmax:

Thank you.

Tom Walz

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[EdStainless]

Here is one more surface prep tool.

http://www.plasmatreat.com/

I have seen system that in-line plasma cleans and then apply primers, either siloxanes or similar.
This addresses the speed question.
There are tailored chemical bonding promoters for various metals and plastics. Using them is critical to reliable and durable adhesion.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[blakmax]

It is important to understand that whatever process you use it is not just CLEANING. A clean surface is a necessary but not sufficient condition for adhesion. Adhesive bonding is a chemical process that involves reactions at the interface as well as reactions to cure the bulk adhesive material. The surface must not only be clean, it must be chemically active to enable those reactions to occur, hence the need for rapid processing, because any delay may lead to the formation of undesirable hydrated oxides. Thus the excellent comments from Thomas Walz.

However while a clean and chemically active surface may produce short term strength, for long term durability a third condition must be met. You need to develop a surface which is resistant to hydration, otherwise as I stated further back in this discussion hydration will lead to disbonding.

One of the most badly understood aspects of adhesive bonding is the use of strength or even fatigue testing to validate surface preparation processes. If you understand that hydration drives almost all longer term bond failures, and that hydration is time dependent, then static or fatigue test results will depend greatly on the time since processing, rather than the loads applied. Some time back I ran regular courses on adhesive bonding and had candidates prepare two sets of specimens; one they tested the next day and the other lot they set aside out in the environment for the next class to test. The results were staggering. The short-term tests for processes which did not address hydration performed only marginally lower than for specimens prepared using processes which are known to produce durable bonds. Yet the samples prepared by the earlier class showed a clear difference, and in some cases companion specimens which produced good results in the previous calls actually failed in the hands of the candidates before they could be tested.

Of even greater concern, most designers rely on damage tolerance to manage defects which occur in service. In almost every case the tolerable defect size is established by either tests involving an artificial defect such as a Teflon insert or by FEA where element nodes are disconnected. Such approaches are totally invalid because they assume that the adhesive surrounding the defect is pristine. This only occurs immediately after manufacture. If a defect suddenly appears in service it is almost always interfacial failure due to hydration (in metals). In such cases the assumption that the adhesive surrounding the defect is pristine is invalid because for hydration if a disbond occurs then the adjacent interface is also going through hydration and as such the strength is substantially reduced. Just google my website for papers which explain this.

The only defence against interfacial failure is prevention by use of a process which resists hydration. You can not manage it by design or damage tolerance.

The science of adhesive bond failure forensics is an area where knowledge is sadly lacking, even at the air crash investigation level. I have run a number of courses in this field.

Blakmax
Adhesion Associates Pty. Ltd.