Tempering very hard steel

[doubleboost]

Hi
Lads
I have some parallel steel dowel pins
They are that hard if you put one in a vice and hit it with a hammer it will snap
I put a few in the log burner last nite , (also great for drying welding electrodes) this morning they can be filed and machined
Would I just re temper it with water like silver steel (drill Rod)
Or do I need Sperm oil :jaw: :jaw: (10 40)
I am wanting to make a centre punch for a video project
Regards
John

[DaveH]

John,
I assume you are just going to harden and temper the 'pointy bit'.
It is quite a small cross section oil or water I don't think it will make much difference.
What I can say hardened and ground steel dowels are usually made from a Moly alloy steel and are oil quenched.

DaveH

[doubleboost]

Hi
Dave
I have got a few cooking in the wood burner
I will have a bit play in the morning
At least I can soften them
John

[TomG]

John,

They could be either O1 (BS 1423) or Silver Steel (BS 1407). To be safe you should try quenching in oil first. If they don't get hard, then quench them in water. If you quench O1 in water, it will likely crack. Since you are making a punch, it will need to be tempered to 460F after hardening.

Tom