The Behemoth has arrived

[SteveD]

I'll give that a go, Daab, before I start chest beating at them. You really DO know everything

[Orfy]

Most stainless isn't completely rust proof

Depending on the grade.

Plus if they have use a lower grade steel for the welding rods then that maybe the problem. I should imagine at the cost involved quality is not going to be the main design criteria.

On the plus side I have read that after machining SS can loose some of it's quality that resists rust but heating it can help develop it again. I can't remember why it happens but I'm sure I've read it.

[Andy]

Wonder if Vossy has had rust issues ?


Talking of which - where is the man

[SteveD]

Did he have a pot from the same source?

[tubby_shaw]

Most stainless isn't completely rust proof

On the plus side I have read that after machining SS can loose some of it's quality that resists rust but heating it can help develop it again. I can't remember why it happens but I'm sure I've read it.

It's due to the fact that like aluminium, stainless steel relies upon a very thin layer of oxide formed on the surface of the material to prevent further oxidising (rusting). So, break that surface film of oxide by machining or as DaaB said by penetration from carbon steel during grinding and the protection is reduced Heating it up speeds up the oxidising process giving back the protective oxidised layer
DaaB you are absolutely correct the term is to passivate
Yes I am a mad metallurgist

[tubby_shaw]

In a very basic way yes the % Chromium alloyed into the steel has a direct relationship to the corrosion resistance. Adding other alloying elements, Nickel being the most popular can increase the "strength" of the oxide film but as you are aware from your machining experience also affect the mechanical properties .
The passivated term comes from the oxide layer being highly stable and unreactive or "passive"
No more now, I am likely to bore people to death

[prodigal2]

No more now, I am likely to bore people to death

Don't worry about it, carry on its great to learn about how stuff works

[tubby_shaw]

while you have your metalurgists hat on...why do stainless steel nuts and bolts have a tendancy to 'fire up' or gaul (sp)...and why does Devtap work so well

You'll have to explain a bit more about what you mean by "fire up" or gaul I have never come across those terms before
Devtap I am a from a cast metals background my normal contact with machinists goes like this mainly " and i'm fu%$*ng telling you that the metals fine! Try buying some new cutters you tw&t "

[TheBigEasy]

Daab,
I hope this explains things.

[tubby_shaw]

Sorry it's me, gaul, gall (not a critisism on you ) I read that and thought French?
As Jon's link explains it's due to the shearing forces exerted on the oxide film that causes it to bind.

[Andy]

ZZZZZzzzzz......

[crow_flies]

think you need to repost here....

[prodigal2]

[SteveD]

[SteveD]

I am likely to bore people to death

No, I am more likley to bore people to death....and so is my wife!