K 360

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K 360

Messaggioda Aldebaran » 03/05/2010, 22:05

It 's a good steel.

Forging is possible, but has several problems.

1.Before foremost that of decarbonization, which will be more extensive and profound than what happens in academic low alloy steels. This is because the K360 It contains a good amount of chromium (8.75%).

2.Secondariamente the difficulty of forging, due to the content of primary carbides present all'ustenizzazione (at a temperature of forging short).

3.Inoltre quenching and tempering should be done with a very good oven, using tricks to avoid decarburization (controlled atmosphere or candy).

Forging may still have beneficial effects on K360, such as grain refining and fiber direction del'acciaio, but ESR technology allows for a fine grain apart, evenly distributed carbides and fine.

Here is' an interesting article

http://www.stav.biz/press/metalli-sett-Ott-07.pdf

If you like, if you do not have the K360, you could use his "poor relation", the Sleipner (which by the way an artisan Scandinavian forge successful, even if the problems are pretty much the same as K360).

Or there 's also the Krupp 2990, very similar in composition to K360 (but not manufactured with technology ESR) *.

Starting from the definition of Ac1 and Ac3 **, forging just below the austenitic temperatures Ac1 and Ac3, respectively 1040 ° and 1080 ° C. to avoid processing, the segregation is not a problem, mainly occurring during the casting during the transformation from liquid to solid ...

Ac3 but 'for the K360 do not think there (is the splitting of Ac1), because it is a steel ipereutettoide. I know the place is Acm, ie the temperature at which all carbide enter into solution in the iron range (Acm practically indicates the saturation index dell'austenite). In any case if there were too Acm would be well below 1040 ° C, given the hardening temperature of the K360.

Regarding the decarburization, the steels with high chromium undergo decarburization deeper than low alloy steels such as AISI O1, O2, 5260, 52100, etc..

But when you go to forge a blade, then you have to remove much more than a few tenths, at least from the surface of the bevels. So for that I do not think there are problems, if you know the first estimate decarburization.

The K360 is a self-hardening to beyond 1040 ° C structure, with cooling in still air, it becomes quite hard. Probably even in still air is hardening. Doing an experiment with D2 (1.2739), analyzing two specimens hardened and tempered with the same parameters, one off in a forced air and in still air, and the result 'was 58 HRC for both.

Indeed this may be a problem, especially if you can not heat evenly throughout the knife (because the small size of the forge, for example).

However already shaping around 900-950 ° C believe that the problems would decrease, since the hardenability at that temperature, would be "limited."

These problems (high hardenability, decarburization deep) are common to many steels, including the Sleipner, but are forged successfully (to produce knives). So I think with a little 'experience and congnizione cause, they can be overcome.


* In the ESR steel is higher than the transverse resilience (closest to the values of longitudinal resilienz).
With technology you can distrinuire ESR in a homogenous carbides (always avoid or limit that segreghino second preferred orientation), as well dimiuire their size. [S
] ** [I] = Ac1 temperature at which, during heating, the formation of austenite starts
Ac3 = temperature at which, during reheating, ending the transformation of austenite into ferrite
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Aldebaran
 
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