Quench Oil Replacement

[forging82]

Hi,
I am new at my job and in charge of the quench oil. We got it tested this spring and it looks like it is at the end of its life. We have 2500 gallons total. The last time all of the oil was replaced was in 2006 and it was reconditioned in 2009. I am looking for advice on what to do. Can this oil be reconditioned again? How often should the oil be tested and when should oil be replaced or reconditioned? The oil is used maybe 4 times every 2-3 months. I have the test results and can upload them if they will help.
Thanks.

 

[redpicker]

You would probably get the best advice by discussing your concerns directly with a quench oil supplier. In my experience, most of the major suppliers are very good at letting you know what your best options are and how to get the best life out of your oil.

rp

 

[dbooker630]

When you say the end of its life there can be several reasons for this: low quench speed, water content, contaminants, high viscosity. Yes, please upload and we can take a closer look. One or more of these are usually the case.

If the speed is low the oil supplier may have an accelerator chemical that you can add. Sometimes a centrifuge can be used to clean up the oil. Viscosity if too high can cause testing problems. When my oil got to the point where it could not be tested due to viscosity I would get rid of it.

The AIAG CQI-9 Heat Treat System Assessment (Process Table A) guidelines call out quarterly testing at a minimum for water content, suspended solids, viscosity, cooling curve, total acid, and flash point.

 

[swall]

Forging82--I just went through this myself. My company had purchased another hot coil spring producer and they never changed their quench oil--they would just replenished what was lost through oxidation and drag out. After about 6 months of our ownership, the newly purchased company had an outbreak of quench cracking--the oil had speeded up to the point where the time in vapor phase had shortened considerably. Our oil supplier was a well known oil company but support to the quench oil product line was non existent. We ended up going with one of the established quench oil suppliers. There was little change in quench oil price and a monthly oil testing program was part of the deal.

 

[forging82]

Thanks for all of your responses. The only person I have to discuss the oil with is our Wallover sales rep. I know it's her job to sell us more oil so I was hoping to get feedback from someone without a financial interest. I uploaded what our last sets of test results were. The last time anything was added to the oil was in 2009.

 

[swall]

In looking at Wallover's report, I note that quench speed is reported in seconds per ASTM D3520. This is the GM magnetic ball test, which only gives you the time it takes for the ball to cool to 671F, the Curie point. This is a very limited view of how the oil is performing. The ASTM D3520 spec has been superceeded by ASTM D6200, which gives you a full time temperature chart. Wallover has the capability to report the quench behavior per ASTM D6200, as I have some of their cooling curves. I suggest you ask Wallover to update their methodology for the testing performed on your oil. Does Wallover provide you with active recommendations based on the oil test results? That should be part of any testing program.

 

[TVP]

I would agree that the oil is at the end of its life: hasn't been replaced since 2009 and the trend is increasing neutralization number (more acidic = more breakdown) and reduced quench speed. The viscosity is already above the specification limit. I do not believe your vendor is trying to screw you over.

 

[dbooker630]

I compared your viscosity readings to some of my recent reports. Your quench speed of 15-16 seconds is slightly slower than the typical 'fast' oil that is 8-12 seconds. The viscosity readings are similar to my oils which range from 83-110 SUS, but most fall within the spec your supplier has on their report. Considering that your oil is clean and free of water, I would use quench speed as the governing factor. You don't use the oil often so dragout is not an issue as it is at my shop. If you are not have issues with quench cracking or core hardness I would keep this oil as is.

The only problem I see is if you are subject to ISO or CQI-9 audits and what is contained in your control plan about reacting to results such as this. My supplier does not put specs on their report, they only make comments such as "add xxx if metallurgical properties cannot be obtained" if a parameter is outside of their range. As long as you can document through metallurgical test that your product meets specs, and that there are no internal or customer specs telling you how to handle your oil, I would leave it alone.

 

[forging82]

Thanks again for the input. I will look into how they test the quench speed from now on. I haven't really gotten a clear answer from them on what we should do. We have already been having some issues with hardness on some of the quenched parts. My dilemma is do we recondition some of the oil to get better properties now and then are stuck doing that every year or do we just start fresh and then come up with some plan for testing and replacement/refinement. We are ISO 9001:2008 certified but I don't recall seeing anything about the quench oil in our procedures. I will have to talk with management about whether or not we want to create a procedure for the quench oil testing because that could confine us in the future. As of right now none of the customer specs specify anything regarding oil life, just temperature.

 

[dbooker630]

I believe you should have some kind of protocol for testing and management of quench oil. If I was an auditor and I saw this report from this past April I would have asked what are you doing about it. Since you are having hardness issues (hard or soft?) you have justification to go to your management to replace the oil, which is the easiest fix. Wallover may also supply (sell) individual oil components that you can add to your oil since you do not use it often. I would also pull a more recent sample since it has been 7 months since the past test. You may even want to have another supplier test the oil. But definitely contact Wallover and see how they improve their service to you as swall recommends.