METHOD OF THERMO-MECHANICAL TREATMENT OF TITANIUM ALLOYS Russian patent published in 2009 - IPC C22F1/18 

FIELD: metallurgy.

SUBSTANCE: invention refers to non-ferrous metallurgy and can be implemented in airospace and rocket engineering for production of engine pilons and load-bearing units of nose domes of rockets operated under high temperatures. The object of the invention is to increase ultimate strength at higher temperatures (σ_us ³⁰⁰) and strength rupture (σ_50h ³⁰⁰, σ_100h ³⁰⁰) and to decrease dispersion of mechanic properties across, lengthwise and by height of titanium alloys. Treatment of titanium alloys is carried out in ten stages with heating to temperature above and below the temperature of polymorphic transformation and with deformation. In the first three stages deformation is performed in four steps changing direction at 90° alternating shortening and drawing at each step. Deformation is executed in one step alternating direction of deformation at 90° from two to seven times in stages from the fourth to the tenth. Upon the tenth stage there is performed ageing at temperature (T_us-320÷T_us-520)°C and holding during from 2 to 10 hours. Quenching is made before ageing at temperature (T_us-120÷T_us-230)°C succeeded with cooling in water or in air.

EFFECT: invention increases strength at 15-20%, decreases dispersion of mechanical properties 3-4 times, reduces weight of parts at 15-20% and enhances operational reliability of units.

3 cl, 1 tbl, 3 ex