heat treatment oil

[kenre]

Hello,

Im currently machining some model racing engine crankshafts out of 9310 (en36A)

I wont need to carburise or nitride the first few but will want to heat treat to increase the properties.

I have the heat treat specs for this alloy, but am after info on the best 'oil' to quench. Im hoping a gas fired oven is also acceptable for heating as i have one already. ( used for Investment casting).

Ken

 

[redpicker]

You really have to consider section size in addtion to the alloy to choose the proper quenching oil. 9310 is very hardenable, however, so just about any quenching oil should be fine (if they are small enough, a good forced air cool may suffice). Water quenching would also be an alternative if you could control things (timed quench) enough to bring them out at around 500 deg F and air cool from there. Of course, regardless of quenching method, you would have to temper to improve the toughness to a useable level.

My big concern is scaling of the surface. You don't have to worry about decarburization much with the 9310, but in an open atmosphere, you will scale up. Plan of finish machining after heat treatment.

rp

 

[dbooker630]

If you can work with a surface hardness of 35-40 HRC then I agree there is no need to carburize. Otherwise I would carburize at 1700F and diffuse at 1550F before quenching. I use Park AAA quench oil in my operations at a temp of 150-175F and it works well for either carburizing or neutral hardening.

 

[swall]

The use of 9310 is inappropriate unless you carburize it. Austenitizing the uncarburized material in an uncontrolled atmosphere and oil quenching alone will not lead to a satisfactory outcome. You would be better off using 4140 and allowing for stock removal after hardening.

 

[kenre]

Thanks for the replies. Surface hardness isnt critical in this application. Toughness more so. I want to avoid carburising to reduce any brittleness, as some sections are thin. This is a problem with the part i am reproducing.

Quenching oil is a special oil with a sole purpose then? No common engine/trans fluids are appropriate? Air cooling could be possible as the parts are approx 65mm long, 6mm dia for 25mm, 12mm dia for 35 and 25m Dia remaining. Bored to 8mm Dia for 35mm. Parts wil be finished ground for final sizing as fit is critical.

 

[swall]

The starting stock of quench oils and engine oils is the same--a mineral oil of appropriate viscosity. They differ only in the additive packages used to arrive at a product appropriate to the end use.

 

[kenre]

OK, Where can i source some quench oil? All searching so far has come up Zero. Would i be better off looking for some chicken teeth?

 

[CoryPad]

http://www.houghtonintl.com/content/view/179/935/

http://www.intensivequench.com/

http://www.heatbath.com/Products-link-page.htm

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[kenre]

Cory, Great links! Thanks.

Only prob is im in Australia, any links for downunder?
Cheers Ken

 

[TVP]

kenre,

Houghton is headquartered in the US, but it is an international company. They have several offices in Oz. Use the following link for more information:

http://www.houghto.com.au