Plate Preparation,Microstructure And Mechanical Properties Of High-Performance Grade 1 CP-Titanium

High strength,low density,and excellent corrosion resistance are the main properties that make titanium attractive for a variety of applications.Examples include chemical processing equipment aircraft,aero-engines and biomedical devices.Chemical titanium material is accounted for the major part of our Country commercial pure titanium.Due to none alloy element and low impurities,the low strength property could not meet the customer requirement and development trend of the chemical titanium.Therefore,it is essential to prepare the high-performance Grade 1 CP-titanium plate.In this paper,multi-pass plane strain compression of Gr.1 CP-titanium was carried on the Gleeble-3800 thermal mechanical test machine.Flow stress behavior at elevate temperature,microstructure and dynamic recrystallization were investigated.According to the simulation results,effects of rolling routine and heat-treatment on the microstructure and mechanical properties of Gr.1 titanium plate were studied.The flow stress behavior of this material was researched by Gleeble-3800 thermal simulation test machine.The strain rates were 1 S^-1～20 S^-1,the deformation temperatures were 650℃～800℃ and the maximum true strain was 1.05.The microstructure of commercial pure titanium after high temperature compression deformation was observed by optical electron microscope,SEM and TEM.Critical recrystallization strain decreased with the rise of temperature and decrease of deformation rate when dynamic recrystallization occurs,the linear relation between critical dynamic recrystallization and the peak of strain was thatε_C=0.4676ε_P.By using the thermal mechanical test machine,it conclude that the annealing-state titanium own the finer grain and better performance than the quenching-state’s through comparing the microstructure and mechanical performance of two initial states.Based on the result of simulation,there are two rolling process routine under different initial rolling temperatures.The plate gauge was rolled from 15 mm to 4 mm through seven-pass.The rolling force increased with the rolling temperature decreasing and the each pass reduction increasing.After heat treatment,theδ4 mm titanium plate’s grain level was increased from level 8 to level 10,the mechanical properties reached the standard Grade 2 CP-titanium of ASTM-B265 as well.Microstructure and properties of the Gr.1 titanium plate were investigated on six-high reversing cold rolling mill under different strain deformation.It was conclude that theδ2 mm titanium plate’s grain level was increased from level 10 to level 12,the yield strength was higher than the δ3 mm plate.Finally,mechanical properties of the two gauge plate could meet the standard Grade 2 CP-titanium of ASTM-B265.