Reaction of Titanium and Steel

Just curious, but how does titanium react with steel?
I sell screws used with watch cases and the screws may also be used
with titanium cases.
These are dive watches (all types of water).
Someone posted the following on a watch site.
"Ti and SS have different oxidation reaction. In normal wearing, water
gets in and that's in addition to the regular air oxidation.
Result is kind of "welding" effect between the 2 metals"
True or false?
Thanks in advance
DON
Reply to
DON
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Pure Titanium is completely inert, but screws are often an alloy.
It is feasible to get a reaction of between stainless steel and titanium if in salt water or sweat.
I can't imagine it happening fast or even very strong, but on a tinu tiny screw it could be too much. The solution would be to use a tiny tiny drop of anti-seize to prevent the threads from welding.
I would recommend that on titanium and stainless steel anyway since both posess extremely thin oxide layers that easily gaul and cold weld to themselves.
Reply to
Ernie Leimkuhler
Hi, Ernie.
IIRC, at the Ole Lazy B, it is strictly forbidden to use tooling of any stainless steel or cadmium in contact with the work when machining titanium...
I always assumed this was due to the possibility of chemical or galvanic reaction in the presence of cutting fluids.
Any ideas as to exactly why this would be ???
Reply to
PrecisionMachinisT
Titanium and stainless are both way down on the electrchemical series and so should not be a big problem when used with each other. Not to say no problem, but I would not expect any.
Titanium has a real problem with chlorine, Freon, and other halogen compounds. It will absorb them and then if it is subjected to elevated temps , the titanium is greatly weakened. Since Titanium is often used because of its strength at elevated temps, I think the reason is that Boeing does not want any contact of the titanium with the cutting fluids used with stainless. You also should not clean Titanium with Trich or Freon for the same reason.
Dan
"PrecisionMachinisT" wrote in message
Reply to
Dan Caster
As I recall from an article in Air & Space, all the SR-71 mechanics had "special" tools that did not contain any cadmium because the trace amounts left on the Ti would cause it to become brittle and fail. Ti becomes fairly reactive at elevated temperatures and its affinity for carbides and other harder cutter materials causes it to absorb them and become even harder and degrade the cutting cutting edge so that marginal benefits are gained. This leads to HSS being one of the preferred cutter materials for Ti.
Reply to
nic
" This
That is not true. HSS will cut titanium slowwwllllly. Some of the new coated carbide inserts will run almost ten times the surface feet per minute of HSS does and leave a better finsish. It doesn't like any chlorinated solvents or coolants that are chlorinated, they cause surface cracks which lead to failure.
Charlie
Reply to
Charlie

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