Water Quenching

[kb0fhp]

great info and chart thanks !!

 

 

where did the chart come from ??

 

D. Scott MacKenzie, PhD

Heat Treating (Aluminum and Steel)

Quenching (Water, Polymer, Oil, Salt and Mar-Tempering)

 

 

is this a book ??? i didnt see it on amazon ??

 

 

I am trying to remember - I think it is in one of my books on quenching of aluminum - or heat treating of steel. It may be in both - I am shameless to use in multiple sources.

[kb0fhp]

Scott,

 

Have you ever seen similar data on water quenches with ultrasonic aggitation... or any other medium with ultrasonic aggitation?

 

Mike

 

 

Ultrasonic quenching in water has been used - it was first cited by the Russians a long time ago in some post WWII literature. I had to strain to translate it. It has also been tried for aluminum with good results. Trouble is that you use a lot of energy to get the ultrasonic energy into the part. It is easier just to use an impeller.

[kb0fhp]

i have read the salt helps prevent a vapor barrier from forming

 

 

Yes - salt acts as a nucleation site for bubble formation and makes the vapor phase less stable. Try a bit of surfactant in it (aka super quench) to make it faster.

[kb0fhp]

I'd love to hear Scott's take on this. Brine is faster, all else equal. I have read that it's also less harsh, and I don't think the two claims are necessarily inconsistent. The explanation I've read is that the vapor jacket phase of the quench tends to cause really uneven cooling, creating internal stresses. The salts in the brine disrupt the vapor jacket phase and eliminate those stresses. Or something like that.

 

Scott?

 

Brine is faster - the relative ranking can be done using Grossman H-Values:

 

http://www.quenchtek.com/pdf_files/technic...y%20Factors.pdf

 

It can be made faster with surfactants, etc.

[Mike Krall]

Brine is faster - the relative ranking can be done using Grossman H-Values:

 

http://www.quenchtek.com/pdf_files/technic...y%20Factors.pdf

 

It can be made faster with surfactants, etc.

 

Scott,

 

Where would moving a blade in the quench and using an impeller in the quench fall on the severity factor chart?

 

Mike

[matt venier]

I've been looking at this thread for a while and I have a question. By that chart it looks like a shallow hardening steel (W2 or 1095) Quenched in soft warm water might not harden, am I looking at this correctly?

 

Matt

[kb0fhp]

I've been looking at this thread for a while and I have a question. By that chart it looks like a shallow hardening steel (W2 or 1095) Quenched in soft warm water might not harden, am I looking at this correctly?

 

Matt

 

 

Yep - I would probably say that - especially in the absence of agitation.

[kb0fhp]

Scott,

 

Where would moving a blade in the quench and using an impeller in the quench fall on the severity factor chart?

 

Mike

 

 

Standard metallurgist answer - it depends. It depends on how rapidly you move the part or agitate the oil. Beyond the SA answer, I would relaistically expect most oils to fall in the .2 - .35 range. You can estimate the relative hardness from the correlations of H factor to equivalent round from the old Grossman charts (from Practical Guide for Metallurgists, by Timken - a wonderful text):

Edited May 4, 2009 by kb0fhp