Gränsfors axe steel specification? Heat treating required.

[Calontan]

Hi, A friend of mine (really, it wasn't me!) left his Gränsfors axe in a bonfire and didn't discover his mistake until he was raking over the ashes and found the head! He has asked me to heat treat it for him and I wondered if anyone has done this before (the heat treating, not the burning)?

Anyone got any advice or know the steel spec they use?

Thanks,

Richard

[kossminn]

Have no idea about steel composition (usually it only says "swedish steel") but I would try one of those solutions:
1. land an email to GB and explain the situation, maybe they will help or
2. try heat treating it like normal spring/tool steel, heating it a little above nonmagnetic, then quench in warm oil. Maybe you won't get the same result as a factory hardened GB, but you still have a usable axe.
Hope it helps

[lost hope]

Have you tested the hardness with a file to see if the temper has been ruined ?

[Calontan]

Thanks for the info! I should have gone to the GB website first. They have descriptions of the various processes they put the axes through and this is an extract:

"After the forging and the first step of sharpening the edge, the lower part of the axe head, the blade, is tempered by warming it to 820°C followed by a quick cooling in cold running water. Then the axe head is annealed: kept for 60 minutes in an oven that is 195°C. This relieves the stress in the steel, built up by the forging and tempering processes and gives the bit the desired hardness and toughness. The hardness of the bit is measured, 57 Rockwell C, and enery single head is tested by a smith who, with a big hammer, strikes on the edge’s corners. If the blade does not break the head is good."

Sounds simple enough!

Thanks again,

Richard

[Chris Grant]

Gransfors steel does not have a grade number, it is a proprietary steel made for them.
It is a plain carbon steel very close to 1055 or EN9, for sure 0.55% Carbon.
I have this info straight from Gransfors.

As you mentioned, according to their own axe book, they harden the steel at 820, water quench and temper at 190 for 1 hour.

BTW... Depending on the heat/size of the fire, it might have got too hot, if it was up to orange heat, you might have to normalise the steel to repair the grain....if...

Good luck


CG

Thanks for the info! I should have gone to the GB website first. They have descriptions of the various processes they put the axes through and this is an extract:

"After the forging and the first step of sharpening the edge, the lower part of the axe head, the blade, is tempered by warming it to 820°C followed by a quick cooling in cold running water. Then the axe head is annealed: kept for 60 minutes in an oven that is 195°C. This relieves the stress in the steel, built up by the forging and tempering processes and gives the bit the desired hardness and toughness. The hardness of the bit is measured, 57 Rockwell C, and enery single head is tested by a smith who, with a big hammer, strikes on the edge’s corners. If the blade does not break the head is good."

Sounds simple enough!

Thanks again,

Richard

[ScotchDave]

I would anneal the head before any heat treating, just to be sure that you aren't going to induce more internal stresses than you need to.

Dave

[ScotchDave]

Ooops, double post.

Dave

[Everything Mac]

Offt. I bet he was a happy chappy.

There is a youtube video from the GB guys making an axe. They seem to dip it in oil if I recall.

Though that may have been a different steel.


Best of luck with the HT.

Let us know how it goes.

Andy

[nvg]

Why not send it back to GB...?! They'll be able to fix

[Calontan]

Thanks for all the information.

I 'annealed' it first by putting it into my forge when I'd finished for the day & covering with coke. It cools very slowly so should be OK.

The next day I heated it up to orange-red along the blade edge and quenched in water. It seemed plenty hard enough along the blade and took an edge well.

He has it back now so I'll wait to hear how durable it is.

Thanks again,

Richard

[polemat]

G.B are really helpful, I visited them a few years back on the way back from the nordcap, they showed me around proudly, even though not really open for tours at the time and happily re-furbed my axe and gave me a new sheath. Maybe they felt sorry for how stupid I looked when I showed them the axe..... After a bottle of port I stowed the axe safely in to a log....without taking the sheath off! What an idiot.....and after knowing this they still let me chuck about a huge double headed throwing axe at a target. Brilliant fun!

[roestalker270]

Hi, A friend of mine (really, it wasn't me!) left his Gränsfors axe in a bonfire and didn't discover his mistake until he was raking over the ashes and found the head! He has asked me to heat treat it for him and I wondered if anyone has done this before (the heat treating, not the burning)?

Anyone got any advice or know the steel spec they use?

Thanks,

Richard

This may or may not be useful....

http://youtu.be/dbCpDsxUHVc