Re: Nitrogen & martensite/austenite

  Taran 18:07 13 Oct 03
Locked

Martensite is an acicular, needle-like crystal with body centered carbides.

In the "as hardened" condition (prior to tempering) the steels in question are very hard, ranging from HRC 61-68. Obviously, at this level of hardness, it should go without saying that they are also extremely brittle. Even the much favoured ATS-34 and 400 series with their retained austenite (as much as 30%) and to a lesser extent Sandvic 12c27 can suffer. This is why it is essential to properly temper the steel, reducing the gross hardness, while generally rendering greater toughness and shock resistance.

Sandvic 12C27 is yet another excellent stainless steel from Sweden where its base metallurgic content is proof of the extremely clean source ore from which it is smelted at point of manufacture (Carbon 0.6%, Manganese 0.35%, Chromium 14.0%, trace Sulphur and Phosphorus).

The Cryogenic Quench is a modern addition to heat treating tool steels. After the normal heat treat process the steel temperature is lowered further using a controlled liquid nitrogen soak. The duration of soak time and the number of tempering steps undertaken can greatly affect the final balance of hardness to wear and shock resistance.

If you need specifics for particular allows feel free to ask since the above is a very general overview of your question.

Regards

Taran

  MAJ 18:11 13 Oct 03

OKAY, Who took Taran's tablets away!!!!!!

  Terrahawk 18:16 13 Oct 03

???????????????????

  Taran 18:19 13 Oct 03

Sorry all.

The above was ceratinly not meant for this particular site.

I advise on metallurgy and heat treating techniques on a technical site for some very specific projects and this was a gentle nudge for someone having difficulties.

Clearly my own difficulty this evening lies in successfully multi-tasking between two forums...

Deepest apologies all.

I'll tick as resolved and try not to drop any more clangers.

Unless of course, someone wants to bounce this data around and take it further ?

;o)

Once more, sorry for any confusion and consider me virtually chastised.

Regards all

Taran

  expertec 18:23 13 Oct 03

;-)

  GANDALF <|:-)> 19:15 13 Oct 03

/me prepares to amaze my friends with my knowledge of Sandvic 12C27. The Cryogenic Quench will halt any dinner party in mid-flow. ;-))

G

  Taran 21:35 13 Oct 03

It's probable that I'll never live this down, isn't it ?

;o)

  GANDALF <|:-)> 21:37 13 Oct 03

:-))

G

  Djohn 23:20 13 Oct 03

Well, it certainly woke me up Taran. Thought I'd wandered into the wrong forum for a moment. :o)

  Gandalph 00:29 14 Oct 03

Not to forget of course that the .0004" coating of Titanium Niteride really gives it a hardness hard to cut through.

  Jester2K II 07:42 14 Oct 03

So is there also a poor bloke trying to reboot his lump of Sandvic 12c27 with a floppy disk in the A Drive??

This thread is now locked and can not be replied to.

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