A study of sintered iron-base antifriction materials

Abstract

1. Sintered iron-base materials have better wear-resistant properties than bronze and can operate under higher loads; on the other hand their running-in characteristics are inferior, owing probably to their relatively lower plasticity. 2. The load-carrying capacity of flood-lubricated sintered iron-base bearings at sliding speeds of 2.5–3 m/sec is not lower than that of bronze bearings; it becomes higher at slow speeds. 3. Oil-impregnated sintered iron-base materials can function at slow speeds and small loads without additional lubrication; this gives sintered materials a considerable advantage over compact bearings. 4. Of the materials studied those exhibiting a structure consisting of pearlite with a small proportion of ferrite and cementite have the best antifriction properties. 5. A 3% copper addition reduces the load-carrying capacity of these materials, but increases their wear resistance. 6. Increasing the graphite content (in the original mixture) over 2% causes a slight deterioration in antifriction properties of sintered materials, owing obviously to the resulting increase in the proportion of cementite formed during sintering. 7. Addition of sulfur causes a slight reduction in load-carrying capacity of sintered iron-graphite bearings operating under conditions of flood lubrication and increases it in the case of oil-impregnated materials used without any additional lubrication. 8. Of all the compositions studied the material ZhG-2 with a pearlite structure has the best antifriction properties.