Research On Forming Uniformity Of Quasi-? Forging Of Aerospace TC18 Titanium Alloy

With the rapid development of the aviation industry,the use of titanium alloy materials and the application of forging processes have played an increasingly important role in aircraft manufacturing.As an important high-strength titanium alloy,TC18 titanium alloy is mainly used for the manufacture of large bearing structures and landing gear parts of aircraft.In current actual production,the deformation of TC18 titanium alloy during quasi-beta forging has a crucial impact on the performance of forgings,but there is no very clear understanding,so this article first simulates the actual working conditions for forging experiments and determines The optimal quasi-? forging deformation.At the same time,in the actual production process,there is a lack of summary of the related common problems in the forming process of TC18 titanium alloy.Therefore,it is of practical significance to summarize the design rules of the pre-forgings and the influence of the relevant process parameters on them.The main contents and conclusions of this article are as follows:(1)Under the conditions of the existing experimental equipment(reduced scale die,heat treatment furnace,hydraulic press,etc.),with the help of finite element simulation,determine the basic experimental plan(blank size,pressing amount,heating time,sampling method,etc.),in After forging,three levels of deformation are obtained: 9% ?18%,25% ? 33%,45% ? 50%(equivalent strain interval 0.1 ? 0.2,0.3 ? 0.4,0.6 ? 0.7),and according to the forged parts after forging Size,determine the relevant mechanical performance test plan.(2)Conduct corresponding mechanical properties test and analyze the influence of quasi-? forging deformation on TC18 forgings: With the gradual increase of deformation,the fracture toughness of TC18 forgings gradually decreases,elongation gradually increases,yield strength,tensile strength,impact toughness Then there is little change.Therefore,the amount of deformation that makes TC18 obtain the best comprehensive mechanical properties is 25% ? 33%(equivalent strain interval 0.3 ?0.4).(3)Analyze the forging technology of an aerospace TC18 titanium alloy forging,and determine its technological plan as free forging billet,pre-forging,final forging;with the help of finite element simulation,the main goal of deformation uniformity is to design and optimize the pre-forging.The proportion of effective pre-forged parts in the three typical cross-sectional areas in the effective equivalent strain interval(0.2 ? 0.5)and the optimal equivalent strain interval(0.3 ? 0.4)are greatly increased;with the help of finite element simulation,the process consistency and stability High performance and high material utilization rate are comprehensive goals.The design and optimization of the pre-forging billet and the final billet size are determined.(4)Taking a U-shaped section of the aforementioned forging as a typical section,the effects of soft cladding process,friction coefficient,die pressing speed and die fillet angle on the uniformity of quasi-? forging deformation of TC18 forgings were analyzed: soft cladding The use of the process will reduce the deformation uniformity of the forging;the friction coefficient and the pressing speed of the die are too large or too small will reduce the deformation uniformity of the forging;as the fillet of the die decreases,the deformation of the forging die area increases sharply.The deformation uniformity of forgings is reduced.(5)According to the structural characteristics of TC18 titanium alloy forgings,the forging structure of this type of material is divided into three areas: sample area,U-shaped,H-shaped and other high-ribbed cross-section,thin web area,high height and thickness Very thick rib area;analyze the three areas where deformation unevenness is most likely to occur,and the corresponding solutions;take deformation uniformity as the main goal,summarize the design rules of TC18 titanium alloy pre-forgings.