The ubiquitous Harbor Freight Fireman's hatchet mod

Ok,i see the photo of the break,you've done a great job photographing it.
No,grain-size that large is not acceptable for a tool such as an axe(at least not Desirable that's for sure).
I realize it's magnified but the individual grains Are visible,by the naked eye,and they oughtn't be.
What it may mean is not that certain.I know nearly nothing of HSS,nor of many other alloys it may be,or you may even be right about it being a casting.

If it was me,and i was up against having to use this alloy for a tool,next step would be to see if it's susceptable to grain-reduction by Normalizing.
That involves heating it 3 times,first to just over-critical,then to just crit.,and third time to just below crit.
After each heat letting it cool in still air till black(lack of any invisible)heat.
Then quench again,and make another break.

Now here's the thing about grain-growth:It is a function of being held for long periods at high heat.So after repeated forging heats et c.,right before HT it gets normalized,and all's cool.
But here's the rub.One very important aspect of quenching is Soak-time(at critical T).Each alloy has it's correct time,say plain-C alloys it's 1-1.5 minutes.But for say O1 it's about 30 minutes...
Exceeding this time causes the grain to enlarge(not soaking it enough does not convert enough of the structure to what you need it to become).
Excessive T also causes grain to grow.

So sometimes after normalizing properloy one can screw it all back up by incorrect T and/or soak-time at quench.
(junk alloys are rough to play with,after a while you'll just want to buy a legit,Known alloy,it saves So much hassle!:)

The photos really do make it look werse then it is. To the naked eye it looks like a mat grayish white surface. The grains are not visible

When breaking this piece it was surprisingly tough. I had to hit it quite hard for it to break

With plain-carbon(10xx series)and other "simpler" alloys the loss of existing HT begins at close to 300F
(look up Oxidation colors,they start at Light Straw and go on from there forget my temps in degrees).But that is only as seen on Shined-up steel,otherwise you may miss it.
Cold enough to hold your bare hand on is safe,too hot to touch is beginning of danger zone.

Yeah, I am quite familiar with plain carbon steels. I was hoping this axe to be at least that but it appears to be a much more complex steel.

With plain carbon steels heating to gray (just passed blue) noticable softening will occur. With this steel it didn't. That is why I'm thinking it may be M2 or some other variety of HSS which doesn't really soften until about 1200* f or so
 
To the naked eye it looks like a mat grayish white surface. The grains are not visible

When breaking this piece it was surprisingly tough. I had to hit it quite hard for it to break

Totally.It is entirely possible(even plausible)that the HT of this object,including the grain-size,is absolutely consistent with it's intended usage.
However,since we're having a general gab about the insides of a chunk of steel(especially since we don't know and will likely never know what exactly this is),here's a good example of what's desirable:
A broken old file of a more/less reputable brand(unless casehardened)will exhibit what would be Ideal in grain-size in(especially)a striking tool.
 
I had to hit it quite hard for it to break

Btw,you Did quench it before breaking?(sorry if you've already said that;my comp barely works and any page-change is an ordeal:)

Because if you've broken it with no quench,in it's original HT,then i'd say that something is amiss,(or may well be...a properly HT'd steel is awfully hard to snap...)
 
I heated it to about an orange color then quenched it in water.

Then I mounted it in my vice and hit it with a hammer. I was thinking it would snap quite easy but it took several trys to break it

Btw,you Did quench it before breaking?(sorry if you've already said that;my comp barely works and any page-change is an ordeal:)

Because if you've broken it with no quench,in it's original HT,then i'd say that something is amiss,(or may well be...a properly HT'd steel is awfully hard to snap...)
 
Right on,well,"orange" is pretty subjective...

If you've achieved max.hardness i doubt it would take much effort to snap;most probably you've not reached critical T,and/or did not soak it long enough.
The best way to judge reaching Austenising T would be to learn to see recalescence;barring that try non-magnetic,and add just a bit to that,as in higher.
Try holding it steady at that for about 1 minute(by the clock),then quench in water;try to make it from heat to quench in under 1-1.5 second.

You May get a different result,or you may not...junk alloys...always a stab in the dark...
 
Not my style at , but it certainly looks like a much more expensive axe than it is and than it looked off the shelf.
 
I'm familiar with recalescence. It is hard to see on a piece as small as I am using. For this I'm just going to have to go off my experience with color. I'll try some at different temps and see if I can get better results
 
"If it works I don't worry too much about what steel it is"...

Right on,of course,sensible attitude.
I'm in the same boat,and very short on time as well,so use what i got as long as it's workable.

But i've respect for Backyard for willing to experiment with it too,it's educational and just fun,if you're willing to invest time and energy...
(like taking this new toy truck all apart,just Gotta find out what's inside!:))
 
2nd test piece hardened at a higher temp. about a bright orange, just shy of yellow. maybe 1700* or so. the grain on this one is definitely visible with the naked eye. it was also a lot easier to break. If the grain size grew I assume I overheated it and therefor it seem like it wouldn't be HSS. back to a mystery steel

uc
 
Frankly,i know Zero about HSS alloys...so couldn't say.
(having looked one up,just for giggles,was reconfirmed that my pea-brain won't go there:https://www.hudsontoolsteel.com/technical-data/steelM2)

Btw,is that metal in any manner stainless-like?

For more general thought fodder...came across this photo on one of Mordor forums:
https://imgur.com/htWsM1e
The guy who posted it is communicating with a character in Pakistan who's product that is.
All cast right in the ground,and some of these are ss.
Apparently sell like hotcakes,all that's in the photo going to someone in RF,definitely for resale.
 
HSS in comparison to most common, ie plan carbon steel, has great hot hardness. Whereas you may temper carbon steels at around 400*, HSS is somewhere around 1000* or so. Also being a highly alloyed steel it requires higher temperature to dissolve the carbides. Data sheet states you may need as high as 2200*

It does seem to have similar heat treat protocols to many stainless

What gets me is this steel if it was HSS shouldn't have any grain growth at such low temperature
 
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Well, you twisted my arm and I bought one the other day, ha ha. What did you cut the beard part out with, a grinder? I don't want to remove the spike personally, but I might reduce weight other ways. Either way, cool project and thanks for sharing.
 
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