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Engineered Surfaces to Extend Service Life and Performance

Adhesive Wear Test ASTM G77

The ASTM G77 test determines the resistance of materials to metal-to-metal sliding wear. Utilizing a block-on-ring testing machine to rank pairs of materials according to their sliding-wear compatibility characteristics, this test replicates “adhesive, metal-to-metal” wear. Results are reported as volume loss in cubic millimeters for both the block and the ring. Materials of higher wear resistance have lower volume loss. Friction coefficents may also be established during this test.

Test Conditions

Tested on 3000 meter slide length. Fixed load and stepped load to COF seizure. Mineral oil lubricant used, 30,000 revolutions, 300 RPM and 300 POUNDS FORCE

Adhesive Wear

Adhesive wear occurs when surface asperities on two materials contact under load, which converts relatively low force into super high pressure. Friction results between two points, creating micro-welds (adhesion) that subsequently fracture and cause undesirable fragments that impart abrasive wear to the two mating surfaces. 

Stationary BlockBlock LossRing LossRotating Ring
BiMetallic (FeCr) 0.1370 0.2200 C1000
BiMetallic (FeCr) 0.1624 0.5158 Moly
BiMetallic (FeCr) 0.1990 1.4000 C4000
BiMetallic (FeCr) 0.4000 3.7000 Stellite
BiMetallic (FeCr) 0.1995 4.7000 Colmony 56
Carbide (WC) 0.0207 0.0641 C1000
Carbide (WC) 0.0249 0.2000 C4000
Carbide (WC) 0.1127 0.2966 CPM-9V
Nitrided Steel 0.045 0.0836 C1000
Nitrided Steel 0.605 1.192 Nitrided Steel

Note: This test was mainly done to compare a misconception that a hard coated feedscrew (Ring) in contact with a softer barrel liner (Block) will cause premature wear to the barrel. This test clearly shows that our tungsten coatings do not wear a barrel faster than any other alloys commonly used for wear resistance and actually can increase the barrel life.