BEINITE SPHEROIDAL- GRAPHITE IRON AND METHOD FOR ITS PREPARATION

摘要

The beinite iron is used in the production of details working in conditions of alternating and high impact loads and intensive wearing - crankshafts for diesel and petrol engines, elements for chain machines, and cogwheels. It has a high static and dynamic steadiness against rifts, combined with a high tensile strength and creeping limit and hardness. The beinite iron contains in percent: carbon from 2.8 to 3.6, silicon from 2.8 to 3.2, manganese from 0.1 to 0.5, magnesium from 0.03 to 0.006 and the rest is iron, when needed it contains nickel from 0.5 to 2.0, copper from 0.5 to 1.0 and molybdenum from 0.1 to 0.3. The method for preparing beinite spheroidal-graphite consists of heating up to temperature of austenite formation from AC1,2 + 20 degrees C to AC1,2 + 100 degrees C and retaining at that temperature for 10 to 180 minutes, which ensures dissolvement of carbon and austenite in a quantity of 0.65-0.80 percent. After that the iron is hardened isothermally at a temperature of 260-400 degrees C from 5 to 180 minutes.