Axe steel choices, why are most low carbon?

[veeteetee]

The Finnish axe you are referring to is Högfors 10.

It was made by Högfors foundry using Kymenite ADI (Austempered Ductile Iron), a patented material developed in the early 1970s. The radical axe design came from the company advertisement department assisted by designer Jaakko Ahopalo. The developmental models were known as 10, 20 and 30. Model 10 was the final model and was produced in the early 1980s, but only in limited numbers as there were problems in use with fractured polls.

The axes are extremely rare but luckily I have these two:

If I´m correct there was also a smaller version Högfors 11.

Additional info: just two weeks ago I was able to buy this, an unfinished in-the-rough axe head casting by Rosenlew Pori Foundry, quite similar to the Högfors 10 model. The seller told me that these were given as gifts to customers and that he has one fully finished and hafted version. How this came to happen is a mystery. Please note the additional ridge of material at at the cutting edge, presumably to make sure there´s enough good material for final finishing. As for its scarcity, I´ve never seen one before

 

[Ernest DuBois]

Hey, Ernest. Good to hear from you.

I agree, and if I thought anybody wanted to forge out a duplicate of a tool I had, it’d be well worthwhile. But I read Luca to be compiling a database of manufactured axes, which none of mine are in the “as manufactured” state anymore.

Truly, he should be anticipating the inevitable public demand for “a hatchet just like the one Parker uses”, but I don’t think he grasps the significance of that. Yet.

Also, there’s not just one. Last week I used two different drywall hatchets, a Vaughan mini-shingler, and a lath hatchet similar to yours (for some kindling). So folks will have to pick their poison (unless they want to collect the whole set).

S’okay, when the clamor arises, I’ll generously share the arcane secrets I’ve hidden for so long. Maybe I’ll post them in Spanish, to weed out the insufficiently motivated (or too buried under a pile of chips) Americans. And Luca can have first dibs on translating my scrivenings into German and/or Italian. They’ll be fractional though, not metric.

Thank you to Jake for the insights. Much appreciated.

Parker

Well C since your posting went up just as I was about to hit the post reply button so what I've posted could not have been responding to that posting of yours about your methods and practices,so hopefully there is no missunderstandings.

No, mine was a response to an apparent attempt at mystifying the simple matter description.

 

[catspa]

No misunderstanding bud, it’s all good. Some information is useful, other is not. I just think adding info on my bastard axes to Luca’s database would muddy the waters more than clarify.

VTT, that’s very cool. I’ve never seen one like that before either. Be great to see the finished one, too.

Parker

 

[Square_peg]

It's not really the steel that's important. Rather, it's the heat treatment and design that are more important for axes, hatchets, and 'hawks.
I have a couple of 2Hawks tomahawks. These are 6150 cast ingots with everything that doesn't look like a 'hawk ground away. 6150 is
basically 5160 with a bit of vanadium, and a bit less carbon. It's plenty tough, and still holds a very good edge.

Why do you suppose the U.S.Forest Service has for many decades specified axes with at least 72 points of carbon?

3.2.1.1 S teel composition. The tool head of each type of ax shall be forged from fully killed plain carbon AISI/ SAE steel containing 0.72 to 0.93 percent carbon, 0.30 to 0.90 percent manganese, not more than 0.040 percent phosphorus, and not more than 0.050 percent sulfur. Steel composition of the head shall be determined as specified in 4.5.1.1.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.fs.fed.us/t-d/programs/fire/documents/5100_9D.pdf&ved=2ahUKEwiai8OIofb2AhXiITQIHUGlAtwQFnoECAUQBg&usg=AOvVaw1jqeIndJMD31vsGQWPtfhQ

 

[justjed]

Why do you suppose the U.S.Forest Service has for many decades specified axes with at least 72 points of carbon?

Because It's a government specification, and someone's job was to compile data and write specifications based on needs and perceived 'best available' at the time. That spec is from 1999, so, hardly decades. And it only covers 3 axes of Forest Service issue. And because better design and materials means less time out of service.

The OP's question was WHY so many axes are in low- or medium-carbon steel alloys. The answer is cost. An axe head is a large chunk of steel compared to a knife, generally speaking, very little of which does any actual work, being simply added mass. Also, lower carbon alloys are generally easier, and therefore cheaper, to heat-treat. And a lot of users will never know the difference.

Otzi, the Ice Man of the Alps, had a copper axe with him when he died. It was state-of-the-art, for the time. ANY of the steels used in properly designed and heat-treated axes today will be FAR superior.

 

[Sid Post]

"The Norms of european Countries about Axes recommend, and still do today, a C content of 0,6-0,7% for a good cutting edge retention.

However, the present investigations have shown that high demands must also be made on the toughness. Furthermore, it must be ensured that the toughness is maintained during the cold season, when the felling work is carried out at low temperatures. Higher carbon contents are not advisable, since with proper hardening and thin shaping of the blades, the desired hardness and cutting ability can be achieved at 0.50 C%. As early as 1953, Lüben (Dipl. Enginner) emphazised a carbon quenching and tempering plate melted in the Siemens Martin furnace with a carbon content of 0.45-0.53%."

Source: Die Konstruktionsgrundlagen der Axt, Gottfried Reissinger (1959)

So if you got a thick blade, unlike the 3-5 mm ORIGINAL Iltis or Müller Axes of today, you use no more than ~0,5% of C for the needed Toughness. As is the Case in Müller axes.

As we know Ochsenkopf in their Iltis today, uses 0,6%C, unlike ~1960.
They dont need the Toughness since their (stupid) thick Axes dont break either way and the People that use them dont sharpen them thin (i use 14° on my Müller Biber, Putzhacke and Tiroler Asthacke. My Prandi Dayton can not handle that Angle without bending. So i do not recommend it anymore. If someone interests this, i added this information?)

If you want a Iltis than get an original one from ~1960 (idk when they became bad and fat) or a Müller Biber.


My Müller Biber is 7,9 mm thick, in a distance 80 mm from edge. (Axe 180 mm long)
My Putzhacke 7,8 mm. (Overall blade is thicker quicker, but 20 mm longer so its the samd thickness at this measuring point)
My Tiroler Asthacke 7,5 mm. (Axe is 195 mm long)
(+-0,5 mm, since the thickness changes if you measure closer to heel or toe and how you reference "distance from edge" perpendicular from edge or Nape, bla bla bla)

The original Iltis (the non plus ultra) is 4,9 mm.
The Ochsenkopf Iltis today (I asked Ox by Email).....11 mm...

sad...

sorry for rambling

My understanding of the Ochsenkopf axes is that use C50 steel which I think if 0.5% carbon.

Of the axes available today, which is closest to the original Iltis. Your reference to 11mm explains part of the performance I see when using this axe. That, and a relatively soft heat treat.

I like the overall profile but, wish it was harder and a bit thinner for better penetration in hardwoods.

 

[FortyTwoBlades]

Regarding specifications for Forest Service axes it's largely because of the way the awarding of government contracts work. Someone decides on the specifications for the particular item, which is then put out to bid with various manufacturers, who try to put out as low of a price point as they can while being held to the standards outlined in those specs. The specifications given are not always because they are strictly necessary, but because whoever put together the specifications had to set targets *somewhere*. Granted, they will usually be where they are because they are the specifications the person(s) or committee responsible for putting together the specs thinks those are good or reasonable targets to be hitting, but that doesn't necessarily mean that they're always right, just that that's where they set it.

 

[Allan DeGroot]

The requirement of an axe more than hardness is not to shed pieces of itself and THAT more than carbon, requires Manganese Hammers require similar toughness

 

[Ernest DuBois]

The requirement of an axe more than hardness is not to shed pieces of itself and THAT more than carbon, requires Manganese Hammers require similar toughness

With a compound construction both are achievable at the same time without compromise, which is the beauty of it of course.

 

[FortyTwoBlades]

There's no need for welded construction for that to be achieved without compromise. Whole steel/monolithic construction manages it just fine.

 

[jake pogg]

The requirement of an axe more than hardness is not to shed pieces of itself and THAT more than carbon, requires Manganese Hammers require similar toughness

One must be careful when interpreting the How and Why of the use of specific alloying elements.

Manganese and "toughness" (resistance to deformation) have no relationship as far as i'm aware. Mn is a common alloying element in most steel alloys as it helps to promote through-hardening principle,also,in larger amounts it's characteristic in AR-grades of steel(Abrasion Resistant).

"Toughness" of any completed steel object is an effect of the heat-treatment vs the alloy composition,which translates into the Potential for any physical traits only.

 

[Ernest DuBois]

One must be careful when interpreting the How and Why of the use of specific alloying elements.

Manganese and "toughness" (resistance to deformation) have no relationship as far as i'm aware. Mn is a common alloying element in most steel alloys as it helps to promote through-hardening principle,also,in larger amounts it's characteristic in AR-grades of steel(Abrasion Resistant).

"Toughness" of any completed steel object is an effect of the heat-treatment vs the alloy composition,which translates into the Potential for any physical traits only.

So get to the core of the issue, that these alloys, carbon content excepted, lead to a corsening (relative) of the structure and lmitation to getting readily at the keenest of edges.

This is not to say a stainless, with chromium or whatever, isn't at all sharpenable, but only with high-tech.

 

[jake pogg]

So get to the core of the issue, that these alloys, carbon content excepted, lead to a corsening (relative) of the structure and lmitation to getting readily at the keenest of edges.

Yes and No,Ernest,not sure just how direct the connection may be:

Many things can be meant by "structure". For example the size of grains formed in the last Phase change the alloy underwent.
Grain-size Can indeed be affected by alloy composition,but the last and most decisive factor is the final heat-treatment.
Grain structure does have a bearing on the edge mechanical Stability,in a macro-sense,but not necessarily on the edge-retention in the micro-view(the manner in which the carbides may break away leaving the edge flatter and duller).

Another sense in which a term "coarsening" can be understood is the size of the actual Carbides (that are often compared to pebbles in concrete,i.e. those are the hard particles embedded in soft Ferrite that do the actual work).

Carbide size Is indeed related to the alloying elements,for example the carbides of Chrome are quite a bit larger than those of Carbon,and less angular. Under the microscope they resemble large rounded boulders,it's not surprising that many craftsmen used to low-alloy Carbon steel feel the cutting action as "slippery",with little or no "bite" to it.It takes more energy to initially embed such edge into the material.

Probably when speaking as a woodworker (also a butcher), the plain-C steel cannot really be excelled for it's combination of factors,vs the detriments that are also inherent to it.

But for different other applications where extra-long edge retention,corrosion resistance,or resistance to high operating temps then the high-tech high-alloy steel comes into it's own...(also for those folks just trying to keep pushing the boundaries of edge-holding ability for whatever (often impractical) reason).

 

[Ernest DuBois]

It's all what I meant basically, ( and i always assume we're going on and on about edges in relation to wood only. )

In my workshop, since i'm a pretty frugal guy, i've two sets of planer blades. One carbon for the finest work, but the edge lasts a relatively short time. One hss, never truely sharp but reasonable for a long time.

 

[jake pogg]

Ernest,here's an article with some neat micro-photographs showing what the edge of your hss blade looks like,and how it interacts with an abrasive.
(Your hss may have carbides of different elements than the carbides of tungsten and molybdenum shown here but the idea is similar).

Carbides in K390

I’ve titled this article “carbides in K390” with the idea that it will be part of a series that aims to help understand the role of carbides in knife performance and sharpening. T…

scienceofsharp.com

In contrast to that the plain-C steel is strengthened not by these relatively large carbides but by the single atom of carbon (only about 0.01 um dia.),encased by the structure of iron molecule the bonds of which are under a Very great tension. That tension,and the many dislocations of the crystalline matrix caused by those entrapped atoms of C is the Martensite phase,and translates itself into what we call hardness.

Together the above effects combine to form a softer (vs Carbides) material yet one that is more homogeneous and uniform,making it easier to form that fine long sharp edge.

(Hope i'm not being too obscure and confusing,frankly i'm struggling at the very edge of my own understanding of these basics of strengthening of steel alloys).

 

[Ernest DuBois]

Thank you very much for that Jake . I mean those pictures make it very plain to see the consequences of the recipe chosen for the given steel mixture and that there's no getting around the physics.

 

[FortyTwoBlades]

Ernest,here's an article with some neat micro-photographs showing what the edge of your hss blade looks like,and how it interacts with an abrasive.
(Your hss may have carbides of different elements than the carbides of tungsten and molybdenum shown here but the idea is similar).

Carbides in K390

I’ve titled this article “carbides in K390” with the idea that it will be part of a series that aims to help understand the role of carbides in knife performance and sharpening. T…

scienceofsharp.com

In contrast to that the plain-C steel is strengthened not by these relatively large carbides but by the single atom of carbon (only about 0.01 um dia.),encased by the structure of iron molecule the bonds of which are under a Very great tension. That tension,and the many dislocations of the crystalline matrix caused by those entrapped atoms of C is the Martensite phase,and translates itself into what we call hardness.

Together the above effects combine to form a softer (vs Carbides) material yet one that is more homogeneous and uniform,making it easier to form that fine long sharp edge.

(Hope i'm not being too obscure and confusing,frankly i'm struggling at the very edge of my own understanding of these basics of strengthening of steel alloys).

K390 is not high speed steel, but rather a high vanadium cold-work tool steel. High speed steels are alloyed in such a way as to improve their "red hardness" or their hardness when hot from use in machines operating at high speed/friction. The mechanisms at play with high speed steel in Ernest's case will depend on the specific grade, but generally will not be like what is shown in that linked article, as the roughly 1% vanadium found in most high speed steels is for refining grain structure and improving its high-heat hardness, not for carbide formation.

 

[Artyh]

5160 is an excellent steel for large blades, like swords or axes. It has a carbon content that is similar to that of 1060. I wouldn’t buy an axe made of 1095, but I just got one in 1060. For very light work, I suppose that you might get away with a carbon content like you see in 1095 or O1, if hardness were RC 55 or 56 or so. However, I would see this as light hatchet territory, rather than axe work. I have a large Kabar machete in 1095 that has been useful to remove saplings in the backyard. I doubt that it was hardened beyond 52-54 or so. It worked fine and didn’t chip when it hit the ground. I am far from an expert here, but high carbon content is not always best. It depends on what you want the tool to do for you.

 

[garry3]

Well,Sir, i'm afraid there's not an easy way to tell. Probably the least destructive would be to polish a spot,etch it with Nitric,and put it under a metallographic microscope. (what it translates to is a friend in a lab somewhere).

However,the good news is that the casting of steel in general is often misunderstood-a cast-steel object does Not equal a poor,inferior quality product,not in any general sense.

ALL steel has been cast at some point,the question is how well the process was controlled as far as what went into the mix,and how it was cycled thermally or mechanically in the subsequent stages.

The main difference for us,the non-metallurgists,is the Cost. Casting is significantly more expensive,from what i understand as much as 8x more than Forging.

To begin with,you'd be Very unlikely to run into a cast-steel axe-head.
Historically the idea was appealing to manufacturers,and apparently many,including W.C.Kelly had/(have?) patents registered attesting to that effect (anecdotal evidence for me at this point,alas i never got off my duff to research that closely).

In practice though,for reasons of economics or other,we don't really hear of any mass-produced cast axes until shortly before WWII,when Keech in Australia patent their famous "Keechsteel" products. (These are excellent axes,produced for several decades (not sure until when),and very sought after to this day).

After WWII the idea came up less and less. I'm aware only of a Finnish manufacturer Hogsfors who tried,and failed,to produce axes by casting in the 1970-ies. Otherwise all was quiet on the casting front.

Today to my knowledge only Ivan Tasev,in Bulgaria,is still experimenting with the process. He's an excellent metallurgist,and has gotten a hold of some dinosaur soviet equipment to play with,and is actually producing axe-heads that are cast.
He sells his tools on ebay under the handle "mapsyst",and also has a site,you may try http://axessive.com/
(He's a nice guy,very approachable,possibly you can pick his brain in regards to details).

Other than that again the odds of running into a cast axe-head are rather long,it was never a practical Or a cheap way to produce axes,and again-the result would in no wise be of an inferior quality,not for reason of it being cast in any case.

Cast heads were the cheap alternative in their day. I think every hardware store chain sold them. Their was also some cast iron axes offered and being sold as such.
I think some of the racing axes are cast and isn't Jauregi starting with a cast head?


41-6

 

[jake pogg]

Cast heads were the cheap alternative in their day. I think every hardware store chain sold them. Their was also some cast iron axes offered and being sold as such.

It's a tricky,loaded term,"cast"...So are many others,as used in advertisement of yore...Just look at that (cool) catalog page alone,at how the word "forged" is used: "Forged"-"Forged steel"-"Forged from a good quality steel"-"Forged from a special analysis steel"-"Hand forged"-there's a topic nearby currently where the emotionally-charged side of "hand-forged" comes out -but what does any of it Mean,exactly ?!

Does some/all of that come from Commerce,or does it go further back,to that eternal habit all metalworkers had for Mystifying?

You're right,it appears that "cast" has,of old,this less-than connotation.... However,with the advent of Huntsman,the "crucible steel process,many of the best tools displayed "cast steel" proudly,front and center.

I've tried my best to make head or tail of it all,honestly. White and grey cast iron,ledeburite and malleable,lamellar stucture or...(the other one!...All just ended up a hodge-podge in me poor brain.

CAN one make a cast iron axe-head? I can see the eye holding up,but what about the edge? My Vulcan anvil is cast iron,with a steel face cast Into the body,an innovative,proprietary American process that was the state of the art in it's day,so maybe something similar?

And cast Steel head-how exactly would that differ from forged? Why "finest cast steel" is the best,and says so on the most expensive plane-irons then available,but a cast head be somehow inferior?

I'm at a loss,frankly.