In the preceding dissertations, the pros and cons of using of Mineral Oils and Water-Glycol Solutions for High Pressure Die Cast Machines were tackled, and both were given consideration as viable options.
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HFDU oils, synthetic and fire-resistant, presents itself as possibly the technology that provides the best balance between performance (lubrication), and fire-resistance, albeit at a higher unit cost. Essentially formulated from both organic and inorganic esters, plus additives, HFDU oils are anhydrous, or non-water containing. In general, Fire-Resistant Synthetic Lubricants (HFDU) fluids, especially as compared to mineral oils and water-glycol fluids, exhibit the following properties,
- Higher Viscosity Index – thus, providing a wear-reducing lubricating film despite elevated operating temperatures,
- Excellent Rust and Corrosion Protection for both ferrous and non-ferrous metals – performing at par with mineral oils, and significantly better as with HFC fluids,
- Improved Pump Protection – as signified in pump wear tests, such as with the Vickers Vane V104C test
- Stronger Resistance to Oxidation – field experience has proven oil lifetimes that is 4 to 5 times longer than with competing technologies. This is due to HFDU’s higher resistance to the formation of acids which accelerate oxidation.
- Can operate at pressures up to 400 bar, and at designed pump speeds, unlike with the lower pressure and speed ratings of HFCs
- Fire-resistance – while not as fire-retardant compared to the water-based HFCs, the fire-resistant properties of most commercially available HFDUs are sufficient to pass Factory Mutual’s (FM) ratings on fire-resistance, a testament to HFDUs safety features.
In handling Fire-Resistant Synthetic Lubricants (HFDUs) however, ensuring that there is minimal water contamination is imperative, as the excessive moisture reacts with the HFDU components to form harmful acids. As a rule of thumb, moisture of 2,000 ppm is established as a maximum limit. Solid particulates need to be controlled also to ensure optimum performance, wherein NAS Class 9 is considered as the upper limits.
For more information on HFDUs, one is encouraged to view the white paper of Quaker Chemical’s Ronald Knecht — https://fluidsolutions.com.ph/fire-resistant-hydraulic-fluids-steel-mill-ronald-knecht-quaker-chemical-corp-usa/