Forging by Kamis

Rail Spikes are not rail tracks. Thats a Tottaly differnt usagage I would say one has trains running on it, lots of friction & compresion, the others are big nails driven into wood..

Rail tracks reputation in kukris is that its less springy & harder if forged the same way {but presumably more brittle?}. It was commonly used up to & including WW2 in kukri.

But old rail track is also often damaged, cracked & broken, thats why it gets dumped in the scrap yards.

This website explains a little about Railtracks.

http://www.msm.cam.ac.uk/phase-trans/parliament.html

Gives info like "The first steel rails used anywhere in the world were laid in Derby station on the Midland Railway in 1857. The metallurgical structure of those rails was essentially the same as that of the rail steel still used today - a pearlitic structure based on a carbon/manganese composition.

Pearlite comprises a mixture of relatively soft ferrite and a hard, brittle iron carbide called cementite, taking the form of roughly parallel plates. It achieves a good resistance to wear because of the hard carbide and some degree of toughness as a result of the ferrite's ability to flow in an elastic/plastic manner.


Microstructure of PEARLITIC rail steel. The interlamellar spacing is about 0.3 micrometres. This is a colour enhanced image in which the cementite is light blue and the ferrite is black."

But sadley not steel industry number/names.

I am sure 15 minutes on Google could find out the exact types though.


Spiral
 
tinmaddog said:
I can't add much to this conversation, but as far as rail steel goes, isn't it a lower carbon steel? I remember seeing some rail spike knives online and one of the smiths making them said that they didn't hold an edge as well bc they were only about .3% carbon (as opposed to 5160, which is .6%, right?). Does anyone know if the actual tracks are closer to a 1060/5160 type steel than the spikes?
Click to expand...

After a google search and 15 minutes of reading, I think rail steel is made from a wide variety of materials. It's a performance specification, rather than going strictly by chemical composition. There is rail steel, and Improved rail steel.

From this webpage http://www.key-to-steel.com/ViewArticle.asp?ID=62

"Medium-carbon steels are similar to low-carbon steels except that the carbon ranges from 0.30 to 0.60% and the manganese from 0.60 to 1.65%. Increasing the carbon content to approximately 0.5% with an accompanying increase in manganese allows medium carbon steels to be used in the quenched and tempered condition. The uses of medium carbon-manganese steels include shafts, axles, gears, crankshafts, couplings and forgings. Steels in the 0.40 to 0.60% C range are also used for rails, railway wheels and rail axles. "

Steve
 
Thanks Steve, as you say lot of different alloys doing the same job then. .4 to.6%. carbon.

I cant see old railway tracks would improve the quality in comparison with old lorry & car springs. Some would appear equivalent some not.

But old tracks would have been taken up for a reason anyway, one presumes.

Spiral
 
Pounding a rail section into a khuk has got to be a job.

>>>>>>

You know, as I gather old leaf springs from the prarrie here, there's a mix of wagon, tractor, truck, car etc.
I don't know what I'm getting.

When people talk about steel improving with age in knives, does that also apply to these springs?



munk
 
Its Funny Munk & on this one I may be mistaken but I think the slight advantages of great age probbably are nullified at red heat & reforging.

I love the Victorian shear steel myself for meat cutting knives & I guess that could be reforged to great effect withot any loss of effciency, but where could one ever find a source for it in kukri sizes?

Spiral
 
The only Yoga I ever practised was climbing mountains and sitting on them, sometimes in very strange positions.


munk
 
I had no idea that steel improved with age. Thats interesting.
 
munk: when you say "sheet steel", what do you mean?

good quality bar stock/etc is going to be expensive. as in very. perhaps dan or somebody could opine what a piece of khukri sized metal ready for stock removal and/or forge to shape would cost. not cheap i'm guessing.

thin sheet steel will need extensive prepping if they intend to fold it, which is going to require flux and blowers and high temps, yes?

anything too thick... like rails... you've seen the videos on how they cut over sized springs? esp wide one, and of course, they come too long, and need to be cut down. heat heat heat and then pound score lines and snap. i'm going to guess that if they introduce a crack at this stage, it's all for naught. especially if you get an internal fault that you don't notice.

frankly, i'm impressed with the blades i have, and their quality given that the source metal came from a dead truck, was heated and beated and came through in a new shiny form. good stuff.

bladite
 
The improvement theory, if I recall, comes from the fact that when you harden steel, you get martensite ( assuming you hit the target temp fast enough), which is a brittle, high stress grain structure within the steel matrix. Great edge holding but brittle. When you temper, the point is to hold the steel at a temp where the matrix is 'loose' enough to allow the martensite to change to a less stressed form (like pearlite,cementite, et al ). This decreases the brittleness of the blade making it tougher. The thing is, it is costly and time consuming to repeatedly cycle blades in a tempering process to convert most the martinsite to other forms...so, what most production processes do is convert enough martensite ( i.e. one or a few tempering cycles) to give a moderate level of toughness but keep costs down and production up...

Now, martensite will spontaneously but slowly convert on its own. So theoretically, an older blade will have a lower level of unchanged martensite and hence would be tougher. I think if you reforge or heat a blade to red heat and requench, you would undo any time imparted benefit...of course, you could then give it a better heat treat than it had to begin with and you'd problably end up with a better blade reardless.
 
Indian/ Nepali price for barstock bears no resemblance to US prices Bladlite.

Very different economy. It would cost more than junk yard steel, but several other kukri houses buy it in ,buy the lorryload on occasion.

In various grades ranging from the lower grade ones for the tourist shop sales , then high carbon British & Nepali army grade, on to what seemed to me to be a very high grade spring steel stock..

Each succesive grade obviously cost more. But in actual dollars not much out there, on each individual kukri price..

Spiral
 
spiraltwista said:
Indian/ Nepali price for barstock bears no resemblance to US prices Bladlite.

Very different economy. It would cost more than junk yard steel, but several other kukri houses buy it in ,buy the lorryload on occasion.

In various grades ranging from the lower grade ones for the tourist shop sales , then high carbon British & Nepali army grade, on to what seemed to me to be a very high grade spring steel stock..

Each succesive grade obviously cost more. But in actual dollars not much out there, on each individual kukri price..

Spiral
Click to expand...

interesting then... the kind of stock i think about when i say "bar stock", tends to be of the absolutely pristine guaranteed chemistry dimensional tolerance best of stuff i guess. i know there are vastyly many grades.

i'd guess even there's reconditioned grades, where someone aquires and recycles the stuff themselves, grinds off the rust, etc and sells it as not quite junkyard but cheaper than high grade stuff.

so. perhaps something for HI to consider as a secondary source... perhaps a "higher grade" khukri level for sale. premium. mmm...

bladite
 
I guess when I say, "sheet' I dont' mean ten gauge, and when someonelse says 'bar' I doubt they mean a two by four. Yes, another quality khuk company does use what I and they have referred to as 'sheet steel"; this is not the same thing as cheap material. I've heard it referred to as decent quality stuff.

munk
 
Well the Indian steell companys now own the British steel industry as well & supply springs to many car makers arounnd the world direct from India, so I guess they can supply any spec & tolerance wanted.

10 years time the Indian prices will have gone through the roof I think, but its still cheap at momment.

I know & can appraise blades but I dont know enough about the chemistry of steel types.

As you say I am sure thier can be grades amongst the scrap sources to ranging from "falling apart" to "looks as good as new" :D

Spiral
 
I think you can buy any type of steel required from India,any grade, in any size or shape you want.

Spiral
 
munk said:
For instance; If I took a leaf spring, and gradually by heating and pounding turned it into a rod, a crack would still be there?

munk
Click to expand...

Yes. And if you tried to immediately hammer it into a round rod, without forging it 6 or 8 sided while forming it and reducing it in size, you would propogate the crack and create more.
 
There have been questions of a simple charcoal forge getting hot enough to weld. They do, and easily. Charcoal is the fuel that was used by all metal working cultures until 200 years ago, and it is still used throughout the 3rd world. Pine charcoal is the fuel that the Japanese smiths used for smelting their iron and forging their blades. Charcoal burning forges and foundries were so prominent that they were responsible for a large portion of deforestation in the eastern usa, before the homesteaders even got a chance to cut down a tree.
 
Here's a question for the ages:

I have khukuries from several sources: HI, a few Toras, one Windlass, a few antiques, a few from Sgt. Khadka. As I've said in the past I've noted considerable difference in how they etch, both in the process itself and how they look afterwards; the speed of the etch, color of the resultant oxides, and even the smell of the process (and the steel itself) are quite different between the manufacturers and sometimes within a single manufacturer. I would go so far as to say that I could tell a 2004-2005 vintage HI* from the others -- and might be able to tell a Khadka from a Tora -- based upon smell alone, never mind the other cues. Bear in mind that the smell that I'm referring to is after the degreasing process but before the actual etching, although the etching itself increases the odor quite a bit.

Is this a function of the alloy used, the heat treatment protocol, or both? Or something else?

And another question...is it normal to be wondering about how steel smells? ;)

*My last few HI's from this year smell differently.
 
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