hardening of 1045 steel

[petedie]

Hello,

What effects would air, water or oil quenching have on 1045 steel if a section (1/2 wide x 2 high x 3/16 thick) is heated with a oxyfuel to red hot condition? Would I regain or keep the microstructure/hardness?

I have a clicker cutting die (44 HRc body, 52 HRc cutting edge) where I need sharp corners and without heating the blade will crack. But if I heat it, I loose microstructure and hardness. Any other suggestions how to regain hardness would be greatly appreciated...

This thread is addition to my earlier postion - induction hardening..

Thanks for your input.
Pete

 

[Yallapragada1022]

As per ASM Heat Treater's Guide, 2nd edition, page 184:

A quenched hardness of at least 55 HRC can be achieved if properly austenitized and quenched. The quenchants can be water / oil /polymer.

You will have martensitic structure after quenching. The structure will not be martensitic if you just let the part cool in air an you will also loose the hardness.

Hope this helps.

Rao Yallapragada

 

[Goahead]

Heating in an open flame is not recommended.
Heating in a furnace will guarantee homogeneous temperature and sufficient time for the carbon to go in solution.
Provisions should be taken to avoid decarburization, otherwise surface hardness will suffer.
Tempering should follow.

http://www.welding-advisers.com/

 

[TVP]

Grade 1045 is not really a suitable tool material unless you are cutting something that is extremely soft. It sounds like you need an appropriate tool steel that has high hardness and good toughness at the hardness level. Depending on the temperature of the material being cut, there are any number of alloy tool steels that will outperform induction hardened 1045.

 

[petedie]

We are cutting leather/fabric so 1045 is very good to us, but the problem is bending it to a tight/sharp corner. To do that we need to heat it which softens the material but destroys the microstructure.

So the next step is to atleast partial reintroduce the hardness back - go from 30 HRc to 44 HRc. Furnace heating is not an option as it will turn the die to a pretzel.

pete

 

[TVP]

Why not use EDM or some other form of precision machining to obtain the desired geometry? Then all that would be needed is to remove the surface "white layer" and hand polish to the desired surface roughness.

 

[Steve898]

To your original question--the air quenching may not be sufficient to get a hardening effect, unless you use clean compressed air, which might work, thin section have been hardened this way. Be careful.

Oil quenching--I have had good experience oil quenching 1045, even though 1045 is classified as water hardening steel. I used to heat a section of a part that was 1/4" thick with a torch, and once it was hot enough, tapped the part with a bar in my left hand, sliding the part down a chute to the quench oil bucket. The part was hot for about 1-2 seconds, so there was very little decarb. Parts were always over 50 HRC. It would take me about an hour to set up and run over 100 pcs, we charged about $250.00 for each setup. I got about $10.00 of that. Again, be careful.

Water quenching--It will get hard, and there is a risk of cracking. Just don't get it as hot as for oil quenching.

I advise tempering after any of these quenches in the oven at 300F for an hour or more to reduce brittleness.

I hope this helps.