| 摘要 |
The invention concerns a process for improving the characteristics in respect of fatigue strength and toughness of worked Al alloys in the treated state, by means of a thermo-mechanical treatment which is carried out on the cast and possibly homogenized product. It comprises the following steps: (a) casting an initial product along an axis XX' by a known method (b) optional homogenization (c) upsetting in the hot state, preferably by means of a press, along the axis XX', with an upsetting ratio (initial length/final length along axis XX')>1.4 (d) drawing in the hot state in the direction of the axis XX', with a rate of working (initial cross section/final cross section, considered perpendicularly to the axis XX')>1.5 (e) compression in the hot state along an axis perpendicular to the axis XX', with a rate of reduction (initial cross section-final cross section/initial cross section)>15% (f) rolling, hot extrusion or forging, under the usual conditions, and the usual operations for quenching and tempering with possible relief of stresses by cold working (states T6, T651 or T652 for example). For equivalent mechanical characteristics, it makes it possible to increase by up to 50% approximately the characteristics in respect of fatigue strength or toughness in the treated state.
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