metal file for stainless steel

sarabande

sarabande

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I've hurriedly put together a couple of stainless luff groove slides. Very rough stuff, I know, even after I have had a go with a linishing pad and angle grinder..... :(

DSC_00151_zpsw4fe5r1i.jpg


My normal metal files don't make much impression on smoothing out the welds and sharp edges.


Can some kind techy recommend a good make of files for stainless please ?
 
We always used grinders to finish off SS Welds. You can file welded SS but in my experience you need good quality "new" files and they're useless for anything else afterwards.
 
Well I'm not a techy but I don't think you will file it because S/S work hardens once you do that.
You have probably work hardened the S/S already so I'd keep going with the angle grinder and sanding disc. You can polish out fine sanding marks with a "coarse polish" and then use a polish meant for finishing off.

Now having said the above maybe you should read this.
http://forum.weldingtipsandtricks.com/viewtopic.php?f=2&t=5301

Here is a google search on hand filing stainless steel.
https://www.google.com.au/#q=hand+filing+stainless+steel
 
You've also locally hardened it on and around the weld line.
An anneal would take care of that, but not easy to do at home, as mentioned above, probably easier to stick to grinding
 
It would probably help if you anneal it,not sure off the top of my head but you could try heating it to cherry red & then let it cool down slowly that I would say is worth a try.
 
Annealing for stainless is a bit different to other materials, it needs an hour or so at temperature (1000C) followed by a fast cool (water quench will work).
 
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The best files I have ever had come from a ski-shop, used to service skis. They are usually Swiss, not cheap expect to pay £12 or so but worth every penny.
 
prof pat pending said:
You've also locally hardened it on and around the weld line.
Click to expand...

Well I made a similar statement on one of these threads about a year ago and an expert said that S/S does not heat harden and a bit of research showed he was correct.

3.7.2 Heat Treating Stainless Steel | Forging Industry ...
https://www.forging.org/design/372-heat-treating-stainless-steel
Austenitic Stainless Steels — Conventional austenitic stainless steels will work harden with cold working, but cannot be hardened by heat treatment. Annealing ...

Do we work with Austenitic Stainless Steels?

HERE IS A BIT MORE

Jump to Hardening and Work Hardening - 316L stainless steel does not harden in response to heat treatments. It can be hardened by cold
 
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coopec said:
Well I made a similar statement on one of these threads about a year ago and an expert said that S/S does not heat harden and a bit of research showed he was correct.

3.7.2 Heat Treating Stainless Steel | Forging Industry ...
https://www.forging.org/design/372-heat-treating-stainless-steel
Austenitic Stainless Steels — Conventional austenitic stainless steels will work harden with cold working, but cannot be hardened by heat treatment. Annealing ...

Do we work with Austenitic Stainless Steels?

HERE IS A BIT MORE

Jump to Hardening and Work Hardening - 316L stainless steel does not harden in response to heat treatments. It can be hardened by cold
Click to expand...

Welding isn't a heat treatment, it's a change of state :)
The Rockwell hardness value will increase on and around the weld line.
 
If a 300 series austenitic stainless steel is welded using similar filler metal it will not be hardenable by heat treatment. The heat affected zone might have a different grain size but the same hardness.

Work hardening means plastic deformation but filing with a new file does not cause this, although it is arguable that filing with a blunt one might due to local deformation of the cuts. I always grind my stainless welds, simply because it is quicker and easier.
 
vyv_cox said:
Work hardening means plastic deformation
Click to expand...

That has been my understanding so bending will work harden but sawing. filing. grinding and drilling will not. Am I correct on this. I have done quit a lot of polishing with flap wheels and polishing mops. Polishing involves removing material using finer and finer abrasive as I'm sure you know but I have found in drilling and or tapping after does seem to have to cut through a harder surface than the underlying material. Am comment Vyv.
 
Rogershaw said:
That has been my understanding so bending will work harden but sawing. filing. grinding and drilling will not. Am I correct on this. I have done quit a lot of polishing with flap wheels and polishing mops. Polishing involves removing material using finer and finer abrasive as I'm sure you know but I have found in drilling and or tapping after does seem to have to cut through a harder surface than the underlying material. Am comment Vyv.
Click to expand...

Cutting stainless will harden the material if the material removal rate isn't high enough.
Using a blunt tool you can't remove the material at a high enough rate, using a sharp tool incorrectly will achieve the same result.
 
prof pat pending said:
Cutting stainless will harden the material if the material removal rate isn't high enough.
Using a blunt tool you can't remove the material at a high enough rate, using a sharp tool incorrectly will achieve the same result.
Click to expand...

Well yes using a blunt tool will cause rubbing and not cutting. What you are effectively doing is burnishing the material which causes plastic deformation.

When you are welding stainless you can also get chromium migration from the weld site and it need a lot of heat treatment to rectify that.
 
prof pat pending said:
Sorry, but that is incorrect
Click to expand...

By what mechanism? Unless some ferritic alloy is introduced, not normally possible as the filler rod should be either the same composition or higher, e.g. 308 may be used to weld 304, it will all be austenitic and there fore not hardenable by heat treatment. Carbides can be formed in the HAZ in stainless steels of 0.1% carbon but this does not increase hardness, but does lead to sensitisation, a form of preferential corrosion.

Hardness can increase in martensitic stainless steels, 400 series, but not 300.
 
I must admit that I've never researched it, but I'm sure that such research is available.

I'm only going on hands on experience.
The first part of my career was spent in cryogenics machining 300 series materials on a daily basis, including welded assemblies.
 
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