| 摘要 |
FIELD: iron alloys. SUBSTANCE: method of strengthening iron-based alloys containing free and bound carbon, which are suitable in manufacture of structural units and elements, to which elevated strength and plasticity requirements are imposed, consists in smelting alloy, affecting it with pressure and/or manufacturing product followed by transferring free carbon in amount between 0.1 and 100% into iron-bound state by heating it to 723-1100 C and holding it for 0.1 to 100 h at this temperature. Strengthened are separate zones on the surface and in the bulk of alloy and/or product material, which serve as reinforcing elements, by imparting to them heterogeneous structure with different balances of strength and plastic properties using transferring free carbon into bound state on a part of material constituting from 1 to 99% of the weight and/or of the surface by the aid of locally heating material in corresponding zones and subsequent aging. To strengthen surface of alloy material and preserving properties inside material, free carbon is transferred onto bound state in surface layers to the depth representing 0.01-0.90 their thickness. In order to create zones with elevated plastic properties on the surface of material and simultaneously to impart strength properties to layers of material disposed under outside surface and inside material, before the beginning of transfer of free carbon into bound state, 0.1 to 100% of the free carbon is preliminarily removed from surface zones to the depth representing 0.01 to 90% of the thickness of material by heating in oxidative and/or neutral atmosphere at temperature below carbidization temperature followed by aging for 0.1 to 25 h, after which heating temperature is raised to values equal to or higher than carbidization temperature and this temperature is maintained for 0.1 to 100 h. In order to reinforce core of the alloy, transfer of free carbon into bound state is performed by heating internal parts of material followed by aging at this temperature. Weldability of alloy is improved by removing 0.1 to 100% of free carbon on outside surfaces destined for welding to a depth of 0.5 to 500 mm on heating in oxidative and/or neutral atmosphere. Ordering in arrangement of reinforcement zones in material is achieved by performing heating and aging on portions of the surface in the form of points, circles, longitudinal and/or transversal straight of curve lines, spiral lines, and other geometric lines and surfaces, summary area of reinforced parts being maintained within a range of 1 to 99% of the total surface of material. EFFECT: improved strength characteristics of metallic matrix. 7 cl |
