GH4169 alloy is a high-strength Ni Cr Fe base superalloy with Nb, which is mainly used to manufacture high-temperature parts of aeroengine, such as turbine disc, blade, gearbox, etc. The main strengthening phases of the alloy are body centered tetragonal γ "phase and face centered cubic γ 'phase, which have high strength and plasticity, good fatigue resistance and corrosion resistance under 650 ℃, so it is the most widely used high temperature alloy in aerospace field.
The manufacturing process of GH4169 alloy cold roll blade is from the beginning of the billet through many cold rolling deformation, softening heat treatment, intermediate heat treatment and final heat treatment, until the blade with satisfactory microstructure and performance is obtained, which is a complete process chain. The researchers studied the effect of heat treatment softening system on the microstructure and properties of GH4169 alloy, and provided the basis for the establishment of heat treatment system of GH4169 alloy cold roll blades.
In the experiment, GH4169 alloy sheet was cold rolled in 2.5mm thick solid solution state, and the bar was hot rolled in Φ 20mm solid solution state. GH4169 alloy plate is cold rolled according to 10%, 20%, 30%, 40%, 50%, 60% and 70% deformation degree respectively. After cold rolling, 970, 980 and 995 ℃ are selected for softening treatment in box type electric furnace. After cold rolling, GH4169 alloy bars were softened at 970 and 995 ℃, plates were softened at 1000 ℃ and blades were softened at 970 ℃ after cold rolling. The intermediate treatment system is 900 ℃, air cooling, solution aging treatment system is 1010 ℃, air cooling + 720 ℃× 8h to 620 ℃× 8h, air cooling. After the test, the metallographic structure and mechanical properties of the alloy were tested by metallographic microscope and tensile testing machine.
The test results show that:
(1) After cold rolling, the hardness of GH4169 cold rolled blade can be reduced obviously by adopting 970-995 ℃ softening treatment, which is beneficial to the second cold rolling.
(2) The softening treatment at 995 ℃ can obtain better softening effect, and has no effect on the structure and properties of the alloy.
(3) After cold rolling of GH4169 alloy, softening treatment has little effect on the mechanical properties, while intermediate treatment and final solution aging heat treatment are important processes to determine the mechanical properties.
(4) The intermediate treatment and solution aging system selected for cold rolling blades will play an effective role in improving the metallographic structure and mechanical properties.
On 2018-08-08 11:45:46
