大锻件锻造拔长砧型

利用有限元软件模拟了V型砧的锻造拔长过程,并对不同夹角的V型砧压下后锻坯塑性变形区内应力、应变的状态进行比较。结果显示,在117°～153°温度范围内,V型角越大,锻坯心部金属获得的变形量越大,但同时锻坯次表层金属的变形程度减小。为此,将V型砧夹角处的V型砧面改为凸型平砧面,提出了梯型砧锻造拔长工艺。结果表明,梯型砧工艺提高了锻坯内部的压应力水平,使锻坯心部和次表层金属同时获得了较大且均匀的变形,有助于扩大锻坯内部孔洞的锻合范围,改善大锻件的内部质量。

Research on shape anvils for drawing in free hot forging

The V-anvil drawing process of large forgings was simulated using FE software,and the stress-strain distributions in the plastically deforming area were compared after different V-anvils drawings.The results show that the increase of V angle in the range of 117° to 153° can enhance the deformation at the center of the billet,but reduce the deformation in subsurface layer.To avoid that problem,a new trapezoid-anvil,which uses convex flat-anvil face instead of the V-anvil face at the transitional zone,is introduced based on the structure improvement of V-anvil.The results indicate that trapezoid-anvil reduction can make the center and subsurface layer of the billet acquire larger and uniform deformation simultaneously,which is helpful to enlarge the scope of void closing and improve the inner quality of large forgings.