Biodegradable fluids can be a "steel"
Two manufacturers that integrated new fluid technology into their operations prove that high-performance specialty fluids are affordable at last.
If changing to biodegradable or fire-resistant fluids was easy, everyone would have done it by now. But numerous issues have come into play at one time or another: lower performance, poor lubrication, higher costs, greater wear, seal compatibility problems, and long-term stability concerns. It's enough to make one think that the proverbial deck is stacked against these newer fluids.
When Houghton International formulated the industry's first fire-resistant vegetable oil hydraulic fluid, Cosmolubric B-230, many problems seemed to have been solved. This technology made it affordable for manufacturers to make the switch to a biodegradable, oil-based, fire-resistant fluid without compromising performance.
The key to truly testing a new fluid, however, is continuous, daily use in heavy-duty applications. Following are the experiences of Cleveland-based AK-ISG Steel Coating Company and Dallas-based Chaparral Steel, as they changed to Cosmolubric B-230.
AK-ISG focuses on safety
AK-ISG Steel Coating Company is capable of producing 480,000 tons of automotive-quality flat-rolled electro-galvanized steel per year. The mill uses three major hydraulic systems in their production process. Two use water-dilutable hydraulic fluid, but its Nireco Edge mask, used to roll the steel, has a 1,000-gal hydraulic system, which requires straight oil. The pumps, valves, and cylinders on this system need to be continually lubricated, and water-based fluids just can't do the job.
After a devastating fire in 2001 (caused by a spark that ignited hydraulic fluid), AK-ISG became determined to find a fluid that met its performance requirements, yet was also fire resistant. They would take no chance of another fire erupting. After consulting with their fluid supplier for the past fifteen years, Valley Forge, Pa.-based Houghton International, AK-ISG decided to switch to the company's newly-launched Cosmolubric B-230.
B-230 is a blend of natural esters, rather than a synthetic oil. It is made from a canola oil base with a blend of additives that make it fire resistant. Management was convinced of the product's effectiveness after seeing a controlled experiment in which B-230 was sprayed directly into a flame - with no sustained flare-up.
Although the product costs more than conventional hydraulic oil, it provides the same performance characteristics as the previous fluid, making it an easy swap. Fluid viscosity is also a close match.
"Although it is not an extreme temperature application, the Nireco system is sensitive to fluctuations in temperature and the oil quality," says Chris Pace, maintenance engineer at AK-ISG. "Changes in viscosity can change the performance of the servovalves, so we had to have a product with physical characteristics as close to mineral oil as possible."
The hydraulic fluid is also stable, and since the introduction of B-230 in 2001, operators at AK-ISG have not had to change the fluid. The mill uses approximately 1,000 gal per year, which is kept in a tote to top off the reservoir as needed.
Pace explains, "We're very pleased with Cosmolubric B-230. There has been no evidence of oxidation and Houghton's quarterly oil samplings have shown that our total acid numbers (TAN) have remained stable. Houghton also conducts flash point tests periodically to ensure that the fluid has not been contaminated and maintains a high flash point."
Higher pressures usually mean the hydraulic systems have a tendency to operate hotter. The hotter the operating temperature, the more tendency there is for the fluid to degrade. When products degrade, the acidity level increases. Water (condensation) also reacts with ester type products, causing them to have an acceleration in degradation.
As the nation's tenth largest steel mill, Chaparral Steel is a technologically advanced facility that recycles steel into bar and structural products. Their products include specialty bar grades ideal for use in the construction, automotive, railroad, defense, mobile home, and energy industries.
Chaparral's melt shop uses four different hydraulic systems to move red-hot steel out of a furnace and onto a cooling bed, and then into a rolling mill for processing. Each system has a 600-gal reservoir that is just topped off on an as-needed basis.
"In the past, we've had problems with the condensation increasing the fluid's acidity. We tried a lot of different hydraulic fluids, and they all had problems."
Things improved when B-230 was recommended as a cost-effective, highly stable fluid, to combat acid problems while maintaining fire-resistance properties. After switching over the fluid in 2001, Chapparal conducted ongoing testing and analysis. Houghton sampled the fluid on a quarterly basis, as well, testing for acid and other physical characteristics. The fluid has never oxidized, and the TAN numbers have remained low.
"Cosmolubric B-230 has been in the system now for two years, and we haven't had any acid issues. It costs less than other synthetic fluids, and performs as well or better to the fluid that was originally recommended by the manufacturer for use with the system. I love the product, and recommend it to our other mills every chance I get," said Davis.
Tony Noblit is product manager, Fluid Power & Lubricants Dept. of Houghton International Inc., Valley Forge, Pa. Visit Houghton online at www.houghtonintl.com.
The quest for the perfect fluid
The pressure is on. Today's products and materials need to be biodegradable and environmentally friendly, pushing manufacturers to find alternatives to traditional products. This pressure includes hydraulic fluids - hauling gallons and gallons of mineral oil-based fluids as hazardous waste is just not acceptable or cost-efficient anymore.
But until recently, manufactures haven't had much choice. Synthetic alternatives to mineral oil, such as polyglycols and polyol esters, had been priced out of reach for most manufacturers. And those with high pressure and other extreme applications requiring a fire-resistant hydraulic fluid have had to bite the bullet, paying up to six times more for synthetic hydraulic oils than they had for petroleum-based products.
To answer this need, Houghton began a quest to formulate an effective hydraulic fluid based on vegetable oil. Because vegetable oil is a naturally occurring ester, it is inherently biodegradable. It also exhibits good lubricity, on par with synthetic polyol ester fluids. And vegetable oil is a relatively inexpensive base stock. So what's the problem?
The problem is that these vegetable oils have traditionally exhibited low oxidative stability - a critical shortcoming, which prevented their widespread use. However, Houghton continued its research and testing, working with additive packages and using selected base stocks.
The result is Cosmolubric B-230, a Canola oil-based fluid that uses additive technology to successfully perform like polyol esters. It also contains viscosity index modifiers, rust and oxidation inhibitors, extreme pressure additives, copper passivators, and defoamers. These additives have greatly improved the oxidation stability of vegetable oils, so that they can equal the desired characteristics of synthetic polyol esters.
In benchmark tests comparing Cosmolubric B-230 to premium synthetic polylol ester fluids, Cosmolubric was found to provide overall comparable performance in lubrication, pump life, and oxidative stability.
Houghton released Cosmolubric B-230 in 2001. The fluid is approved by FM Global as a "less hazardous fluid." It also passed the ASTM D-665A corrosion test. Among its physical properties are viscosity index of 214, ASTM flash point of 495° F, and ASTM fire point of 610° F - all of these properties at a par with the leading synthetic polyol esters.