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A question about hydraulic oil viscosity - ISO46 vs ISO68
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Reynolds
posted
We have several dozen pumps pumping ISO 46 hydraulic oil and just 8 that are pumping ISO 68 oil. Since we purchase ISO 46 oil in bulk, from time to time we have discussed changing the ISO 68 systems to ISO 46.

The hydraulic cylinders on the machinery using the ISO 68 oil are foreign made and the surface finish is low quality, so there has been some discussion among the engineers that the heavier oil may be more appropriate and less prone to leakage. Those particular cylinders operate at up to 1,000 bar (~14,500 PSI) so I'm skeptical that it would make a difference, but none of us are experts when it comes to the finer details of oil viscosity. There is very little leakage from them despite the poor surface finish.

By comparison, the cylinders which we manufacture ourselves have a very high quality finish and operate at 1,200 bar (through an intensifier) also with very little leakage using ISO 46 oil.

What role does viscosity play with respect to surface finish and or seal material?

What detrimental or beneficial effects might be realized, if any, in changing to the lighter oil?

This message has been edited. Last edited by: Alaric,
 
Posts: 60 | Registered: 25 March 2008Reply With QuoteReport This Post
Pascal
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Alaric,

You are correct that there will be more leakage at a lower viscosity. I would be somewhat concerned that the 68 oil is too thick for your other hydraulic components, specifically your pumps(if you are using piston pumps). I believe you are in Utah?? I'm located in Mobile AL, we use ISO 46 and it is too thick for the pumps' optimum range during the cooler weather. Hope this helps,
Maytag

This message has been edited. Last edited by: maytag,
 
Posts: 186 | Registered: 10 February 2006Reply With QuoteReport This Post
Pascal
Picture of brettl3
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Hi, About 10-12 years back, the plant changed our hydraulic systems over to Super ATF and have had virtually no hydraulic problems or leaks to speak of since the change. The initial concern at the time was leakage due to a lighter viscosity than AW 46,or AW 68..or major wear due to no AW additives. As of the present, no major wear or leakage has been detected. I do know oil will not adhere to a finish of 10 microinches or less, no matter the viscosity....the concern of shear with ATF, we have a regular PM routine that monitors the systems, also with "permanently mounted flow meters", Brett
 
Posts: 187 | Location: Port Angeles,Wa | Registered: 16 July 2009Reply With QuoteReport This Post
Bernoulli
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viscosity does relate with the working temperature.
ISO's VG is measured at 40 Centigrade.
the cooler the temperature condition then the viscosity will increase in number. vice versa.
for me in tropical area ISO VG 68 is recommended.
read the pump's manual for its range of allowed viscosity. check the working temperature range in pump and actuator.
refer to:
http://www.machinerylubricatio...iso-viscosity-grades
pump's spec and the temperature that matters. nothing else.
if else cavitation and non lubricating function occurs.
 
Posts: 9 | Location: Indonesia | Registered: 27 April 2009Reply With QuoteReport This Post
Bernoulli
posted Hide Post
quote:
Originally posted by Alaric:
We have several dozen pumps pumping ISO 46 hydraulic oil and just 8 that are pumping ISO 68 oil. Since we purchase ISO 46 oil in bulk, from time to time we have discussed changing the ISO 68 systems to ISO 46.

The hydraulic cylinders on the machinery using the ISO 68 oil are foreign made and the surface finish is low quality, so there has been some discussion among the engineers that the heavier oil may be more appropriate and less prone to leakage. Those particular cylinders operate at up to 1,000 bar (~14,500 PSI) so I'm skeptical that it would make a difference, but none of us are experts when it comes to the finer details of oil viscosity. There is very little leakage from them despite the poor surface finish.

By comparison, the cylinders which we manufacture ourselves have a very high quality finish and operate at 1,200 bar (through an intensifier) also with very little leakage using ISO 46 oil.

What role does viscosity play with respect to surface finish and or seal material?

What detrimental or beneficial effects might be realized, if any, in changing to the lighter oil?


Dear Alaric,

Thaat's to say you are very familiar with the intensifier manufactures, can you recommend some intensifier manufactures to me? Email:judy@fstcontrols.com
 
Posts: 4 | Registered: 15 August 2011Reply With QuoteReport This Post
Bernoulli
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Which brand of Hydraulic Oil are you using at present?
 
Posts: 5 | Registered: 15 September 2011Reply With QuoteReport This Post
New User
Picture of Lopez Scott
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Till now I was using Premium Hydraulic Tractor Fluid,5 Gal but there some problem with it.It is not allowing the machinery to work fluently.So can any one just suggest is AW32 Hydraulic Oil,1 Gal good for use or not?
 
Posts: 2 | Location: Copper Hill Dr Union, NJ | Registered: 08 September 2011Reply With QuoteReport This Post
Bernoulli
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It's my opinion that you should be very careful altering from hydraulic oil specified viscosity.
 
Posts: 5 | Registered: 15 September 2011Reply With QuoteReport This Post
Bernoulli
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hello Alaric.
it seems that you are familiar with intensifier , can you send some informaton about intensifier design, expeical about the tolerance control and the seal on the high pressure..

my emal: maxinlong55@163.com

thank you..


hi
 
Posts: 3 | Registered: 02 October 2011Reply With QuoteReport This Post
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