The mold-free rolling technology has the characteristic advantage in the double performance turbine disk forming for engine, and it is widely used in the processing and forming of large complex disk parts such as superalloy, titanium alloy, light alloy and steel.
The National Institute of Mechanical Science research began to track the technology in 2003, and related staff did a lot of basic research work, in 2006 developed a small rolling test equipment prototype, but at room temperature only to form a diameter of no more than 280 mm lead plate. In 2009, the team carried out a NUMERICAL control transformation of the original equipment and added a heating system, so as to realize the NUMERICAL control roller forming of the alloy plate, and achieved some technological design results on how to control the distribution of the micro structure.
In order to avoid interference with the roller head, the induction coil can only be placed on both ends of the disc, thus forming the non-uniform temperature field in the low temperature area of the disc center and the high temperature area of the disc edge. For the forming of titanium alloy to form the bipolar area (fine crystal heart alpha + beta phase, plate edge beta phase coarse grain), and double the performance index of turbine disk, the designers give up early isothermal molding of formulation of rolling technology, to put forward the non-uniform temperature field + double performance of forming process characteristic, and through the analysis of the anatomy of TC4 test samples, the distribution of the different organizational results have been achieved.
But when trying to roll the superalloy material, the equipment showed insufficient capacity. In addition, the method of repeated RCC above the allowable forging temperature lacks research value, so it is impossible to carry out in-depth research on the mechanism and process of superalloy RCC. Therefore, at present, the technology and equipment of die - free rolling are still in the stage of basic research.
Along with our country 400 MN, 800 MN die forging press, 360 MN vertical extrusion machine, 200 MN isothermal forging machines and other large equipment served in succession, the titanium alloy and superalloy integral forging forming capacity bottlenecks have been solved, such as the diameter of 2 m weighed 6 2014 t of superalloy turbine disk in China's second heavy machinery group co., LTD. 800 MN die forging press, successful development.
