Titanium's shower of sparks

[Bill Kahn]

I am now playing with titanium. (Well, it is called 6-4 which I think means 6%Al and 4%V). I have noted two interesting features:

1. On the HF 4x6 bandsaw (with a sensibly good blade) I can cut it. And the "saw dust" (doesn't quite seem to be swarf to me) is different from other metal filings. The filings interlock with each other as they fall to the floor. And they collectively form a loose mat. Move some of it and several inches away it is interlocked and the filings move too. It pulls apart easily, but something surprising and unexpected.
2. On the mill, on 1" wide bar, 1 mil depth of cut, 1" feed per 10 seconds, with a 3" 5-carbide blade facer at 2500 rpm--whoa! A regular Christmas display of bright white sparks fly everywhere. Beautiful but I stopped the feed pretty quickly--flying fire isn't of much interest in the shop. If I brought it down to 800rpm no fire. Feed slowly enough and the finish is ok (not shiney through). The sparks lasted long enough to land on Ti swarf. No ignition there. The color was much whiter than the slight yellow sparks I get with some steels. And not the brilliant blue-white of burning magnesium.

I am not making anything with the Ti. Just exploring the material.

-Bill

 

[markba633csi]

Yes they use titanium powder in pyrotechnics for that same reason, as a safer modern-day substitute for Iron filings (which would tend to rust badly in contact with oxidizers)
Mark

 

[BtoVin83]

One time I was making a bunch of titanium pump sleeves and and quite a pile of chips in the chip pan. Making some very fine finish passes on the bore at a high speed and there would be a flash as the fine chips ignited in the sleeve. I then looked at the chip pan and all I could imagine is the worlds largest flash bulb. Man I started raking the chips out of there pronto.

 

[markba633csi]

LOL flash bulb is right POOF

 

[ACHiPo]

My summer job out of high school was metallurgical sample prep of nickel-based super alloys used for turbine blades. They had a very high Ti concentration, and the 60 grit belt sander would throw a lot of sparks, igniting other residue, sometimes on my arms. I tried not to think if the 5 gallon cans of TCE under the bench.

 

[brino]

I am now playing with titanium..........I am not making anything with the Ti. Just exploring the material.

Interesting, I have never worked Ti and have never seen that...

Thanks for sharing.
-brino

 

[JerryK]

I have machined a few pounds of titanium , but never
had any problem with ignition .
These suspension parts for the Rovers Spirit & Opportunity
finish with a 1mm wall thickness, lots of chips

 

[JerryK]

Needed 6 aft suspension arms , so 12 halves , and were
E-B welded together, also 6 rotating joints all titanium.
Picture showing some assembly at JPL in 2002
Launched in 2003

 

[petertha]

Impressive parts!
What does 'E-B' weld process refer to?

 

[JerryK]

Electron-Beam welding

Thanks for the Kudos