Heat Treatment of L6

Dan, it's not a matter of "different grades" of L6, it's that all steels have a range for each of the elements present .Complicating this is that some of the tool steels have optional elements. L6 is one of those with V and Mo as optional. A mill may melt the steel to the high side or low side for any of the elements. This can mean significant differences in properties with L6 from different mills. So it's best to stick to one supplier and learn to handle that particular steel.
 
I far as I know, all of the big band saw blades I've used were 15N20.
I ordered some L6 a few years ago and it was a totaly different anamial.

Don Hanson :D
 
Crucible (champalloy)

Typical Chemistry
Carbon 0.75%
Manganese 0.70%
Silicon 0.25%
Chromium 0.80%
Nickel 1.50%
Molybdenum 0.30%

Carpenter (RDS)

Carbon .70%
Manganese .35%
Silicon .25%
Chromium 1.0%
Nickel 1.75%


always a monkey wrench thrown in some where. :(
I do know they can go up or down on % but
it's interesting that they'd add stuff like Molybdenum and still call it L6?

this stuff is not a problem getting the venders info so I need make sure
it all is coming the same..I tried a test piece from another batch and that one
acts more like the champalloy :( so the problem is to keep track of which ones are which through there use..

one more thing of you will, Kevin and/or Mete.??
is it safe to just determine if it's
one or the other just by heating to critical and letting it cool on it's own? say in vermiculite
to see if has Molybdenum or not? if it softens then is it safe to say
it don't have Molybdenum? or do others make it also, adding a different % of goods and other Chemistry to it? to screw up the works?

thanks guys I got some home work to do, to make sure
 
I wonder how many mills make L6 ? If there are two then you could probably set up a test to separate them otherwise there would be too many variables.
 
you'er bumming me out Mete :( ;)
I think I'm going to find some fact sheets On this stuff from the guys that make it..that's the sure way...Thanks
 
Here in New Zealand bandsaw blades are easy to come by. I cut them with a plasma cutter at the local High School where I work. I anneal them by heating to non-magnetic and put them into kitty litter from the local supermarket, usually about thre blades at a time and allow to cool. To harden I heat to non-magnetic and edge quench in a mix of paraffin wax and oil that is just liquid. I usually end up with a blade where, if it is bent 90 degrees the edge will crack but the blade won't break. Tempering is in a we toaster oven at 120degrees C for an hour. Often I end up with a quite clear temper line on the blades.
 
Cooling in kitty litter ? that's the real cat's meouw !! Wait till Kevin hear's about this, he can put it in his book.
 
huh, Why am I starting a book on uses for kitty litter? If I were to ever write something it would be more suitable for bird cages than litter boxes. ;) I did, however, thoroughly enjoy the book that was out some years back called "101 uses for a dead cat" ;)

I recently have a student who wanted to do a hamon on a blade and we had no clay, but he did have a bag of kitty litter. I gave him some pieces of fire brick, a couple of scoops of litter and another whole brick and let him grind it into a powder on a concrete floor. Mixed it all up with some binder and applied it to the blade. He was pretty pleased with the nice rolling hamon he got ;) (and I thought it was fitting :footinmou ;) )
 
For some time I was only aware of Crucible and Carpenter, but then a third steel appeared that was being sold as L6 that does not air harden. The chemistry given is that of Crucible, but it does not behave like it at all. I have worked with Champalloy for well over a decade now and it has consistantly has the same properties and performance. I tested some of the other stuff and it needs to be quenched to harden it. What I am saying is, unless you can track it back the the exact manufacturer, your guess is as good as mine.

Once again this reafirms the same old mantra that mete and I are always chanting "know your steel, buy good steel, ohhhhmmm..." Time is money, and scrap steel is just too darned expensive for me to afford.
 
Oh yes, I forgot to mention that while the moly will have profound affects on the heat treating, when it comes to easy hardening I would have a look at the Mn content of the Champalloy, in combination with the chrome. The Moly will help this for sure, but it will mostly suppress Ms a bit and really give it a resistance to softening form heat. That is why you can push this stuff up to a 500F., or more, temper and still have it in knife hardness ranges.
 
I thought it was your book titled 'Metallurgical Myths I have Known"
 
Kevin
I realize steel ranges go + or - but when they add so much like these two, called L6
is that normal? say with other steel?
I haven't seen a lot of it.
but a steel being called L6
is that just a generalization of the chem. make up of this one term of steel ?
and how much would/could they add and still call it L6?
it's like you say, know the steel
AND the batches.

or test the batches and follow that heat threat accordantly for that batch.

a complicated journey to a simple target.
What bothers me is, when we take it for granted what we are getting, be it a painted end or it supplied with H/T instruction
printed on the package, it should be all that same but..
we can't know for sure Really what we are getting,, at least most makers..
the only steel I get with H/T instruction marked on the package is the O1..and that's not per batch it's per piece.
which is better than not getting anything..
I know you know all this I'm just throwing it in for the unknowing to make H/T more enjoyable for them. :confused: :)
 
From "Tool Steels" by Roberts ;L6= .65-.80 C, .40-.75 Mn, .10-.40 Si, .75-1.20 Cr, 1.25-2.20 Ni, .15 V(optional), .20-.40Mo(optional).....This is a typical range of elements in tool steels. Variations within the ranges may have a pronounced effect on properties.The mill may have practices that aim at the high or low side of any element to produce certain characteristics such as hardenability etc and do that very accurately.If available you might be able to track down the specific chemistry of the specific heat of steel but for the typical knife maker setting up your own tests for things like hardenability would be a better idea.
 
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