best finishing

[limct]

Can anyone suggest the best plain finishing (meaning no coating/plating or whatsoever) which will demonstrate a rather good resistance to rust (at least no obvious and almost immediate effect caused by the moisture of human finger)

the part is made of free cutting steel.

Thanks a lot.

Best regards,
ct

 

[handleman]

Not sure what you're asking... Steel will rust no matter how smooth/rough you finish it. If you have a plain steel surface with no coating or plating whatsoever it will rust in contact with moisture. A light coating of oil will help impede the rust.

 

[unclesyd]

As posted by handleman plain steel is going to rust in the presence of moisture. Fingerprints are the worst possible thing you can put on a piece of steel. Free cutting steel is about the worst material for fingerprints as the bacteria and acids in skin oils work on the sulphur, normally used in these steel.

About the only why to slow down rust of steel is force an oxide, furnace bluing. Just don’t have a finger print on the metal when you start to blue it.

Any coating oil has to a made for rust prevention.

Could you comeback with the reason for this requirement?

 

[GBor]

limct,

I know companies that purchase the steel intentionally extra-thick and allow it to rust. Iron Oxide is a pretty good rust inhibitor, if I recall my metallurgy correctly (been a few years...unclesyd is a MUCH more reliable source). When the time comes to use the steel for fabrication, they sand blast the surface. Not elegant, but it has worked for decades.

 

[swall]

So is your question, "how to protect (or not protect) steel during storage, prior to machining?"

 

[panduru]

Actually, it should be "how to protect by doing nothing" - which makes eminent economic sense. And when it really works, who is complaining?

I know of many fencing structures "left to rust," so to speak, - and they take care of themselves with the help of the coat of rust formed in the initial days.

Of course, this may not be a permissible option in industry.

As for limct's requirement, a film of oil as suggested by handleman seems the best option, assuming what limct means by "finish" is surface treatment.

 

[tomwalz]

top quality saw plate is shipped wrapped in shrink wrap with a dessicant inside.

Tom

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

 

[NickE]

We ship our parts (1095steel HRc54) in N2 packaging with VCI paper.

I've found that cleaning my hard steel fixtures with simple green and then water/windex and finally a light oil like WD-40 or TKX (CRC) works wonders. (pack in VCI for storage and the VCI paper takes up the excess oil wonderfully)


Nick
I love materials science!

 

[arto]

If you're allowed to goop it up:
Cosmoline - my CMP Springfield from 1944 looked like it came out of the bluing bath yesterday - comes off with elbow grease or easy with boiling water

If you have to keep it clean: Zerust capsules

http://www.ntic.com/capsules.htm

Vci:

http://www.cortecvci.com/Products/products.php

if you go to stainless, be sure to passivate it [ASTM A-967]

lotsa good info:

http://www.cortecvci.com/Publications/Papers/papers.php

 

[Cockroach]

LimCT, you know what I do? Complete the manufacturing as normal, machine your piece to completion. Then liquid nitrate the piece.

This does a few things for you. First and esthetically speaking, the piece will rust a lot less if any after nitration. Second, the increase to surface hardness will offer some wear resistance.

Good luck with it.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[MikeHalloran]

Cor-Ten and related alloys develop an oxide that is self- limiting in common environments. No one who has worked with the stuff would describe it as free cutting.

There does exist one strong alloy that develops a self- limiting oxide and is very free cutting; 2024 aluminum.



Mike Halloran
Pembroke Pines, FL, USA

 

[Pressed]

I have two metal forgings, one is out in my shed and has complete surface rust, flaking a bit. The other was coated with a clear coat spray that I got at Wal-Mart and is as bright and shiny as the day it was forged (six years now) with no rust. Of course it is only a display piece.

Someone sells an anti-corrosion liquid spray, but the performance is less than a year as I remember it.

==========================================
Business Card

http://mech.e.tripod.com

__________________________________________
Cycle Heaven.......

http://www.tailofthedragon.com