Re: Synthetic oil information needed

[Toby Erkson <Toby_Erkson@ccm2.hf.intel.com>]

---------------------------- Forwarded with Changes ---------------------------
From: rlhowell@ix.netcom.com at SMTPGATE
Date: 1/15/97 4:24PM
To: Toby Erkson at HFCCM5
Subject: Re: Synthetic oil information needed
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FYI.
______________________________ Forward Header __________________________________
Subject: Re: Synthetic oil information needed
Author:  rlhowell@ix.netcom.com at SMTPGATE
Date:    1/15/97 4:24 PM


>Mr. Howell,
>Here is the response from a member in our group.  Can you comment on this,
>is his concern valid?
>
>Thank you,
>     Toby Erkson
>     air_cooled_nut@pobox.com
>
>______________________________ Forward Header
>__________________________________
>Subject: Re: Synthetic oil information needed
>Author:  type-3-errors@umich.edu at SMTPGATE
>Date:    1/14/97 7:19 PM
>
...
>This is interesting, but I can't help wondering whether it really is
>responsive to our question.  The problem is that the thermal transfer
>mechanism is completely different at the elevated temperatures mentioned
>here; at high temps the rate of cooling is greatly retarded by the layer of
>vaporized material that forms at the boundary, therefore this test is more a
>measure of volatility than of heat removal.
>
>This test really sounds like one that would be used for determining the best
>material for quenching in a hardening operation, in fact the temperatures
>are just about perfect for that.  In such an application the metallurgist
>will be looking for the material that will produce the desired cooling in
>the desired time, depending on the alloy being considered.
>
>In our case, we are really more interested in data in the neighborhood of
>200F, say 100-300F.
...

Dear Toby:

The objection to using the Quenchometer Test would be valid using lower
viscosity oils such as a 5W30. Those oils have much greater volatility and
can develop a vapor barrier retarding heat transfer. The higher viscosity
grades such as a 20W50 have much lower volatility and do not seem to
develop the insulating vapor barrier.

We have performed other tests which corroborates the Quenchometer data in a
more pertinent temperature range. A 100 gram block of aluminum was heated
to 175 deg C (347 deg F) and immersed in 900 grams test oil at 90 deg C
(194 deg F). The temperature of the aluminum block was plotted versus time.
At 30 seconds the temperature difference of the block was 24.2 deg C for
Red Line 20W50 versus 22 deg C for Petroleum 20W50 A and 21 deg C for
Petroleum 20W50 B. This amounts to a 10% improvement compared to A and a
15% improvement compared to B. This test is conducted in a more relevant
temperature range, but since it is not an industry accepted test, it cannot
be independently confirmed. That is why I chose to use Quenchometer data,
even though it would provide erroneous data with lower viscosity oils.