SLIP-STICK FRICTIONAL BEHAVIOR OF WHEAT ON GALVANIZED STEEL

Test blades of galvanized steel were pulled through wheat to study the frictional behavior between wheat and the blades. The effects of wear and dust accumulation on wheat grains were studied by pulling three b lades through grain samples which had been conveyed in repeated cycles in mass flow and bucket conveyors. The test blades were pulled at a v elocity of 0.05 mm/min and at overbearing grain pressures of 3.9, 6.6, 9.2, and 11.8 kPa. No statistically significant influences (alpha = 5 %) of grain wear or overbearing pressure were found on the coefficient of friction between wheat and galvanized steel. Slip-stick behavior w as observed in all of the tests of the effects of wear on wheat grains . Slip-stick behavior between wheat and galvanized steel was studied b y pulling sir blades of galvanized steel (three new blades and three p reconditioned blades) through a bed of wheat at varying velocities fro m 0.05 to 50 mm/min and at overbearing pressures of 3.9, 6.6, 9.2, and 11.8 kPa. The velocity at which slip stick behavior ended and smooth behavior began was defined as the critical velocity. Pressure had no s tatistically significant influence on the critical velocity. However, a statistically significant (alpha = 5%) relationship was found betwee n the coefficient of friction and the critical velocity.