TB9钛合金芯杆冷镦成形模拟及实验研究

Simulation and experiment study on cold heading for TB9 titanium alloy core rod

针对TB9钛合金芯杆冷镦成形存在的问题,利用DEFORM有限元软件模拟分析了TB9钛合金芯杆的镦制成形工艺,讨论了多工位冷镦成形中变形量、摩擦因数对芯杆镦头质量的影响。进而通过实验分析了芯杆镦头剪切带的组织和力学性能。结果表明:芯杆三工位镦制成形中,采用不同镦制变形量获得了芯杆镦头的应变分布,有效控制了因镦头中心部位变形程度高而造成的镦制缺陷。摩擦因数的减小会降低镦头的应变,当变形量为50%时,三工位镦制成形的摩擦因数为0.35的镦头中心部位的等效应变为1.18874,摩擦因数为0.25的镦头中心部位的等效应变为1.12713,摩擦因数为0.15的镦头中心部位的等效应变为1.07401,提高了镦头的均匀变形程度。通过测试分析芯杆镦头样件可知,镦头内部无微孔洞、微裂纹等缺陷产生,镦头内部形成的剪切带区域的微观组织最密且呈纤维状,剪切带区域的平均硬度为354.8 HV,为芯杆镦头硬度最大之处。

For the existing problems in cold heading of TB9 titanium alloy core rod,the cold heading process of TB9 titanium alloy core rod was simulated and analyzed by finite element software DEFORM,and the influences of deformation amount and friction coefficient of multistation cold heading on the quality of heading head of core rod were discussed.Then,the microstructure and mechanical properties of the shear zone for heading head of core rod were analyzed by experiment.The results show that the strain distribution for heading head of core rod is obtained by using different heading deformation amounts in the three-station heading of core rod,which effectively controls the heading defects caused by the high deformation in the center of heading head.The reduction of friction coefficient reduces the strain of heading head,when the deformation amount is 50%,the equivalent strain in the center part of heading head which is formed by three-station heading becomes 1.18874 with the friction coefficient of 0.35,the equivalent strain in the center part of heading head becomes 1.12713 with the friction coefficient of 0.25,and the equivalent strain in the center part of heading head becomes 1.07401 with the friction coefficient of 0.15,which improves the uniform deformation degree of heading head.Through the test and analysis on the heading head samples of core rod,it can be seen that there are no micro-holes,micro-cracks and other defects inside the heading head,and the microstructure in the shear zone formed inside the heading head is the densest and fibrous,and the average hardness in the shear zone is 354.8 HV,which is the hardest part for the heading head of core rod.