TC6 alloy is a kind of two-phase thermal and strong titanium alloy of martensitic ti-al-mo-cr-fe-si system with good comprehensive performance. Its nominal component is ti-6al-2.5 mo-1.5 cr-0.5 fe-0.3 Si, and its temperature is between 960 ℃ and 1000℃.This alloy not only has the advantages of high specific strength and good corrosion resistance of ordinary titanium alloy, but also has good comprehensive mechanical properties at room temperature and high temperature, the service temperature can be up to 450℃, it is often used in the manufacture of aircraft engine blades, turbine discs and other important parts, but also can be used in the manufacture of aircraft frames, joints and other parts.Domestic of TC6 titanium alloy forgings, castings, optimizing the processing technology and properties of tube rod has done a lot of work, and less on the study of TC6 alloy plate, cold rolling process of the board of scientific research personnel of TC6 control, determine the basic process parameters of TC6 plate cold rolling, cold rolling process performance of TC6 plate is studied.
The experimental TC6 titanium alloy ingot was obtained by three times melting by vacuum self-consumption electric arc furnace, and its transition temperature was 975 ~ 985℃. The specific results were divided into (wt.%) : Al6.2, Mo2.5, Cr1.4, Fe0.41, Si0.29, O0.10, Zr < 0.01, C < 0.01, N < 0.01, Ti allowance.TC6 ingot was used in the experiment to open billet in the secondary phase area and forge billet in the secondary phase area.The slab was rolled hot above the transition temperature and rolled to 3.5mm in the two-phase zone at the temperature of + 2. After intermediate annealing and pickling, the cold-rolling process hardening experiment was carried out.When the processing rate increases by 5%, cut a piece of 200mm long experimental material from the head of the plate and continue rolling the rest of the plate, rolling and sampling repeatedly until the plate appears edge crack or surface crack.Then, 200mm experimental materials with different machining deformation were tested to test the thickness, width, edge crack, structure and mechanical properties of the experimental plate.
The experimental microstructure was observed on the Axiovert 200 MAT optical microscope, and the mechanical properties were tested on the Instron5885 tensile tester.The test results are as follows:
(1) from the hardening curve of cold rolling, it can be found that the tensile strength and yield strength increase with the increase of the processing rate, while the elongation rate decreases gradually. This is mainly due to the increase of the processing rate of cold rolling, the dislocation density and the working hardening.When the processing rate reaches about 27%, the curves of tensile strength and yield strength tend to level, indicating that the deformation stage is difficult.
(2) the maximum cold-rolling rate of TC6 titanium alloy plate can reach 30.3%, and the elongation rate of the material drops to 5.8%. The surface of the plate begins to appear folds and floating protrudes, and cracks appear in the edge.When the processing rate of cold rolling reaches 30.3%, the width is 20mm