What to do if my mystery steel is eating my HSS

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dabear3428

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I acquired a 3"X3" drop of 1" steel that i assumed was A36, i applied my brand new fly cutter to practice squaring up stock it was ruff cut (oxy acetylene cut) so lots of ruff edges, so i'm thinking great i can get lots of practice on some free material. I took the fly cutter (without shaping the HSS and started on it, this absolutely ate the the HSS. I then sharpened some 1/4" HSS (cheap from HF) put clearances on all sides needed and sharpened it with diamond hone, then the steel ate this HSS also. i then switched to a 3/8 carbide 4 flute end mill (cheap amazon) and after cutting some, broke off the ends of the flutes, i then switched to 12mm HSS 4 flute and this cut the steel but it dulled very quickly.

Is it possible that this is not A36 or am i just using crappy tools/technique?
 
Probably a bit of both- You might want to try some cobalt cutters in your arsenal- and use slow speeds/feeds with cutting fluid
Especially when you don't know what it is- could be a high-carbon steel or an alloy
Sometimes it's good to try filing or hacksawing it first- get a feel for how tough it is
It's good that you sacrificed the HSS first- you can always resharpen it
Bargain steel is not a bargain when it wrecks your expensive cutters- Confucious say
How rigid is your setup? Breaking tips can mean less-than-rigid workholding/machine
 
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Flame cutting even mild steel will result in hardening of the cut edges. The carbon in the fuel gas will diffuse into the molten steel and create a very hard zone. I usually grind off the cut edge before machining. Alternatively the cut piece can be annealed.
 
I had a 3" piece of round from a hydraulic ram that had been flame cuts. Most of it turned like butter, but the area around the flame cut had a noticeably different hue, and threw spark when I hit it with the carbide insert.
A flame cut on the big piece of metal like that means that there is a large heat sink to quench that molten metal quickly. You get the extra carbon from the flame, and then an almost instant quench.
 
markba633csi said:
Probably a bit of both- You might want to try some cobalt cutters in your arsenal- and use slow speeds/feeds with cutting fluid
Especially when you don't know what it is- could be a high-carbon steel or an alloy
Sometimes it's good to try filing or hacksawing it first- get a feel for how tough it is
It's good that you sacrificed the HSS first- you can always resharpen it
Bargain steel is not a bargain when it wrecks your expensive cutters- Confucious say
How rigid is your setup? Breaking tips can mean less-than-rigid workholding/machine
Click to expand...
cobalt? is that different from HSS? if so how?
yea this in on a grizzly g0758 so not the most rigid of setups lol
 
RJSakowski said:
Flame cutting even mild steel will result in hardening of the cut edges. The carbon in the fuel gas will diffuse into the molten steel and create a very hard zone. I usually grind off the cut edge before machining. Alternatively the cut piece can be annealed.
Click to expand...
very likely that this is the problem. thanks, see i learned more than i set out to learn, and the hard way no less lol
 
A fly cutter is probably not the best tool to use on flame cut mystery metal. Knock the really nasty stuff off with a grinder, and then get down to clean metal with a roughing end mill, or some such. Then switch to the fly cutter.
 
Speed?

Fly cutter even at a slow rpm is traveling fast.

A carbide end mill can go faster, but it requires rigid mill and hp to bite.

We just start SLOW, increase if needed, but slow speeds to not generate the heat that destroys things.

Shallow cuts also.

Sent from my SM-G781V using Tapatalk
 
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