Timken's Alloy Steel Europe plant in Leicester is a difficult, harsh environment for lubricants, including high performance forming fluids, crankcase lubricants, and greases. The Timken Company manufactures high quality alloy seamless mechanical steel tubing, which is used extensively in the manufacture of components for powertrain, bearing, and industrial applications.
At the Alloy Steel Europe plant, steel blooms (billets) are first heated in a rotary furnace and passed through a piercing mill to produce rough hollows. The hollows are then rolled over a mandrel through an Assel mill to produce hot finished tubes, which can be then re-rolled in one of 13 cold pilgering mills to produce tubes with a high quality surface finish and very close dimensional tolerances. Tubes in both the hot and cold pilgered condition are then used as machining stock for many industrial applications.
Timken has been a Castrol customer since 1992, when a serious oil misting problem in the pilgering mills caused by another manufacturer's water soluble coolant prompted a change to Castrol Fluidform CP.
Commenting on the background to the change, Timken business unit manager Cliff Mallard says that besides the oil mist problem in the pilgering mills, they were also experiencing excessive wear rates in the rack and pinion gears, guides, dies, and crankshaft bearings, and high disposal costs for the large volume of waste fluid.
"We decided it was time to review the coolants that we were using and our control of those coolants," he says. "We also wanted to find products that were more environmentally friendly."
Castrol was chosen because it suggested development of a fluid that would improve the operation and environment of the pilgering mills and at the same time reduce disposal costs. Castrol was appointed sole lubricant supplier to the site. Subsequent trials in the pilgering mills led to the development of the environmentally friendly Fluidform CP, a high performance, long life, fully synthetic forming fluid that is water soluble and pleasant to use with a low odor and misting. At the same time, Castrol introduced Cresta DCX 220, a compatible oil to lubricate the pilgering mills' crankshafts.
"The design of the cold pilger machine means that the coolant and the crankcase oil can mix," explains Cliff Mallard. "As contamination is unavoidable, Castrol developed the two products to be compatible, and both are 'green' and long life."
Cresta DCX 220 has excellent water separation characteristics; it also includes additives to help remove deposits and wear debris in order to maintain crankcase cleanliness. Powerful rust inhibitors also protect crankcase components from corrosion in humid operating environments such as the pilgering mills.
The major environmental benefit of having compatible fluids is that Fluidform CP rejects the DCX 220, which is then easily separated to give greatly increased fluid life. According to Mallard, the result is that Timken no longer disposes of the oil or coolants. "With the change to Castrol products, we have long-life coolants that we top up on a regular basis, and when we clean out the tanks we can put the same coolant back in."
He adds that the same is done for the DCX 220 oil. Instead of disposing of it, Castrol takes it off-site for reprocessing, brings it back up to Timken's specification, and returns it to the site.
The new lubricants were initially tested on two pilgering mills with dramatic results. One produced savings of 40% with waste fluid reduced from 215,000 to 40,000 liters per annum. The other produced even more impressive figures -- a 71% saving with an annual waste fluid reduction from 150,000 to 10,000 liters. Needless to say, Timken extended the two compatible fluids to its other 11 pilgering mills. Mallard reports that besides producing impressive savings and eliminating the misting problem, the new coolant has also improved product quality from the pilgering mills and provides a better finished and cleaner tube. He says crankshaft life has also improved dramatically since Cresta DCX 220 was added.
While Timken currently operates its own fluid management, Castrol is involved in managing fluid supplies and undertakes a monthly stock depletion review. To help schedule maintenance at the plant, Castrol also conducted a comprehensive lubrication survey using its computerized scheduling system. The system enables the Timken maintenance staff to program service intervals and the types of lubricants used. Castrol also takes care of condition monitoring for the Cresta DCX 220 crankcase oil, sending samples regularly to its laboratory at Hyde for particle analysis.
Commenting for Castrol, lubrication engineer Neil Hewitt says the success of the work on the cold pilgering mills has led to other developments at the site, including trials of chock greases and of water-based corrosion preventatives, an appraisal of lubricants used in the finishing processes in the Assel hot mill, and an assessment of Total Fluid Management for the pilgering mills. He adds that Castrol and Timken regularly review the performance of Fluidform CP and are currently investigating concentration levels to optimize fluid usage and achieve further cost reductions.
Summing up, Mallard says the relationship has worked very well -- solving the initial misting problem, achieving an estimated across-the-board saving of 40% on lubrication and disposal costs at the site, and improving the quality and finish of the product.
