New steel I don't recognize

" snipped-for-privacy@krl.org" fired this volley in news: snipped-for-privacy@googlegroups.com:

Don... freshly-cut ends and ground areas do not rust, either! That was in the original post...

L
Reply to
Lloyd E. Sponenburgh
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Good story. My wife, who was raised in central Illinois and who spent summers on her grandparents' farm, said that she was never afraid of the pigs. She was afraid of the chickens. It was their beady little eyes and the aggressive roosters that scared her.

If you saw a comparison with Bonkers, the difference is that clobbering him with a 2x4 wouldn't stop him. He has no sense in that regard. You just have to keep whacking him.

But he makes himself such an easy target that it's not very challenging. It's just a pain in the neck.

Reply to
Ed Huntress

That you invoke comparisons with annoying and biting little animals.

Reply to
Ed Huntress

So if the fresh cut ends do not rust, why did they bother to galvanize it?

Dan

Reply to
dcaster

I'm interested to see what Lloyd's analysts say, but a couple of points: First, galvanizing prevents rust not, primarily, by forming a barrier, but by creating a galvanic cell with the ferrous metal, and the galvanic protection can extend for 1/8" or more into cut areas. You can really see this on marine hardware that's been nicked up. Even exposed to salt water, those bare spots and edges of steel don't rust much.

Second, your point is the one that prompted me to write that (unwelcome) post to Lloyd. They don't galvanize rust-resistant alloys.

I'm betting that it's some plain-carbon alloy -- either a clean piece of mild steel, as Iggy suggested, or, much more likely just based on what simple structural shapes are usually made of, some loosely specified structural alloy (A36, etc.). It could also be Chinese or American re-melt junque -- one of the non-grades of scrap re-melt, like the railroad rails used for bedframe steel, or the dregs used to make coat hangers.

Most structural steel is pretty much crap, to a machinist or a fabricator.

Reply to
Ed Huntress

" snipped-for-privacy@krl.org" fired this volley in news: snipped-for-privacy@googlegroups.com:

Umm.... If I knew that, then I'd not have asked!

I'm going to do another 'wet' experiment, this time with salt in the wound. It could be this stuff was prepared for a marine environment, although I don't recall the use of gavanizing from when I was in the Navy.

Lloyd

Reply to
Lloyd E. Sponenburgh

Work boats often have galvanized fittings. Yachts are stainless and bronze. Small pleasure boats have a lot of aluminum.

The navy goes its own way.

Reply to
Ed Huntress

Well... got out to the shop this a.m. to find something different.

Last night, I sparked out a piece, and it looked for all the world like just ordinary structural steel. A piece of A36 next to it made the same sparks... BUT... for a long time (a couple of seconds of grinding...) no sparks.

So today, I took it back in the shop, mic'd a flange, then ground lightly just until I saw the first sparks, and mic'd it again. There's darned- near 15 mils of zinc on this stuff!

Further, I had treated a cut end last night with potassium nitrate/water slurry. This a.m. there WAS some visible rust on the cut surface. The untreated cutoffs I left out in the dew, now, for two nights are still pristine.

So, even though these flanges are about 3/8" thick, I guess I'll have to go with Ed's surmise that the 'galvanic cell' process is keeping the cut edges from rusting, unless otherwise accelerated to do so.

Huh! I guess I just got a lesson in how good at its job GOOD galvanizing can be!

LLoyd

Reply to
Lloyd E. Sponenburgh

Maybe the soil contained some rust inhibitor that came from the scrap. Were other cut ends rusty?

Reply to
Jim Wilkins

"Jim Wilkins" fired this volley in news:mv8esf$f5i$1 @dont-email.me:

Everything in the yard but this one piece and a piece of 300-series were rusted all to hell. And my cut-ends that were not abused with the nitrate have still not shown a trace of corrosion.

LLoyd

Reply to
Lloyd E. Sponenburgh

I found some references to using an aluminum zinc alloy for coating as well as a reference to a iron zinc alloy for coating. But did not find anything that compared those alloys to plain old galvanizing.

Dan

Reply to
dcaster

Maybe try stripping all the galvanize off a test piece and then see how fast/much that rusts?

Reply to
Leon Fisk

Leon Fisk fired this volley in news:mv8v2m$pn$1 @dont-email.me:

Heh! Not worth the trouble! All I needed was a couple of heavy mount brackets for a pyrotechnic mold, and was surprised by the behavior of this piece.

I think it's solved.

Lloyd

Reply to
Lloyd E. Sponenburgh

My bet is the zinc is acting like an anode and absorbing all of the oxygen that would do the rusting. Just like an anode on your boat to keep it from melting away. It melts away.

Mart> Well... got out to the shop this a.m. to find something different. >

Reply to
Martin Eastburn

To me it sounds like racking for switchgear or high voltage transmission towers. The crossbeams that hold the insulators are generally heavily hot dip galvanized .

Reply to
clare

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