METHOD FOR DETERMINATION OF CHANGE OF PROPERTIES OF SEMIFINISHED ITEMS MADE OF HEAT-RESISTING ALUMINIUM ALLOYS AFTER LONG-TIME HEATING Russian patent published in 2001 - IPC

FIELD: examination of physico-mechanical properties, applicable in analysis of stability of properties of heat-resisting aluminum alloys in service. SUBSTANCE: the method provides for sampling of specimens from the semifinished item in the initial artificially aged state, additional heating of them, test of specimens and determination of the change of properties by comparison of them in the initial state and after an additional low-temperature heating. Test specimens are additionally sampled from the semifinished item, heated at several temperatures within 453 to 493 K during 5 to 100 hrs, after that the specimens are subjected to tensile testing at the room temperature with determination of ultimate strength σ_u and yield point σ_0,2,, coefficient of regression b₀,b₁,b₂ of equation of their dependence on parameters, type lgσ = b₀+b₁/T-b₂•lgτ is found for each property by the method of lowest squares, where T-heating temperature K; τ- duration of exposure, hr; using the obtained equations, strength values and are determined at the parameters of the additional low-temperature heating of the initial specimens, then an intermediate heating of the initial specimens is accomplished up to a temperature within 463 to 493 K during 5 to 50 hrs at a temperature and duration of heating within these limits satisfying the above equations at σ equal to or and the additional low-temperature heating of the initial specimens after the intermediate heating is conducted during 10 to 30 hrs, comparing the properties obtained during the tests of the specimens in the initial state and after the additional heating of the initial specimens the change of the properties is determined. EFFECT: enhanced operativeness of estimation of the change of properties of heat-resisting aluminum alloys at service heating, and, as a result, enhanced capacity. 5 tbl, 3 dwg, 3 ex