The wear tests were carried out on a self-made simulating ensilage-cutting machine. The relative cutting between the fixed and moving cutters was kept at 20.66 m s whilst the cutting period varied from 5 to 360 min. The cutter specimens A, B. C(made from AISI 1090) and D(made from AISI 1045) were used to cut a mixture of water, grass and sand. The dry grass was firstly soaked in water and then mixed with sand which contained 85% silicon dioxide(SiO2) particles of size ranging from 70 to 100 sieves, and with a HV hardness of 1100. The ratio ofthe grass, sand and water was 2.0:1.0:1.5 by weight. The mixture was then fed per- pendicularly to the cutter blades for pre-set periods. The surface condition of the damaged cutter blades was exam-ined by a scanning electron microscope, whilst the wear rate, i.e., the decrease in the dimensions of the knife cross section, was measured by a travelling microscope. When the stationary and moving cutting blades were assembled, a pressurizer was used to maintain a pre-defined gap between them.