Study On Forming Technology Of High Purity Titanium Extreme Strip And Properties Of Single Layer Crystal Titanium Foil

In this paper,based on the domestic production of electronic level low oxygen ultra high purity titanium as raw material,the use of independent research and development of Northeastern University,combination of asymmetric asynchronous rolling forming technology,using the synchronization of two micro four high mill and3 m asynchronous rolling mill,cold rolling at room temperature,respectively,and a middle vacuum annealing process,develop the high purity titanium thin belt rolling experiment research and analysis,the main research work is as follows:1)Using high purity titanium with thickness of 8.6 mm as raw material,after a large number of rolling experiments,the high-precision and high-purity titanium strip with thickness of 25-280 ?m was successfully prepared;2)The mechanical tensile test,microstructure observation and fracture morphology observation of high-purity titanium ultra-thin strips with different thickness were carried out.It was found that two size effect thresholds(140 ?m and35 ?m)appeared in the high-purity titanium ultra-thin strips prepared by this rolling process.It was found that the change of FCC phase band and the increase of specific surface area occurred during the rolling process of high-purity titanium ultra-thin strip,which resulted in the change of FCC phase band and the increase of specific surface area The reason of the phenomenon of twice size effect is presented;3)The variation of tensile strength with thickness of high-purity titanium thin strip was studied.The initial rolling process was optimized.The reasonable preparation process and rolling schedule of high-purity titanium strip were given,which provided reference for the development and actual production of high-purity titanium thin strip;4)Single crystal high purity titanium foils with different thickness were prepared by tube vacuum annealing furnace,and the annealing process of single-layer crystal high-purity titanium foil with different thickness was summarized.The mechanical tensile test and microstructure observation of single-layer crystal high-purity titanium foil were carried out.It was found that the fracture morphology of single-layer crystal high-purity titanium foil was all step like cleavage surface,and its strength and elongation were very thin compared with that of rolled high-purity titanium foil With the increase of grain size,annealing twins will be produced during annealing;5)Combined with the rolling experiment of high purity titanium thin strip,reasonable measures are adopted to solve the problems such as edge wave and medium wave,foreign body indentation,roll scratch and wrinkle crack;6)In the process of rolling,it is found that there is a phenomenon of edge crack healing in the process of thin strip thinning.It is pointed out that the negative roll gap rolling is a favorable factor for the edge crack healing.The edge crack healing phenomenon can improve the qualified rate and utilization rate of products,which provides favorable conditions for the production and manufacture of high-purity titanium ultra-thin strip.