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John Deere Metallurgical Breakthrough Eliminates Bushing Turns

June 1, 2005
SC-2, a new alloy coating for dozer undercarriages from John Deere, provides the best combination of hardness, toughness, wear resistance and corrosion resistance properties of any coating on the market. In fact, SC-2 is so durable that an undercarriage featuring SC-2 coated bushings doesn't need bushing turns to hold up over the long term.

SC-2 coated bushings are compatible with existing John Deere undercarriage designs, and will fit many other brands of dozers, as well.

The John Deere SC-2 Extended-Life Undercarriage features coated bushings that are the result of a patented process called GOPALITE developed by John Deere Senior Staff Metallurgist Dr. Gopal Revankar. The process produces a water-based slurry from a heavy alloy-metal powder and several organic additives. The slurry formula suspends the alloy powder and is used to apply the coating to the part surface, producing a coating that's uniform in both thickness and consistency. The ingredients and techniques used greatly reduce the slurry coating's susceptibility to breaking when subjected to high impact.

Intensive laboratory tests prove conclusively that SC-2 coating is 25 percent harder than chrome plating, according to Revankar. SC-2 coated steel held up four times better than parts not protected by SC-2 in a sand abrasion test. A brutal impact test also was performed in which a 220-pound weight was dropped 500 times on an SC-2 coated bushing from a height of 30 inches and the coating remained undamaged. In another lab test, an SC-2 coated bushing was fractured in a hydraulic press and the coating stayed fused to the steel.

The coating also has been tested in the field for the past three years, running on dozers that work year-round with high-impact loads in extremely abrasive soil conditions, including fine sand. Each dozer had one chain with SC-2 coated bushings, and the other chain was equipped with normal production bushings.

Source: John Deere, May 23, 2005