Influence of drawing practices on Co-Cr-Ni wires using FEA
Khoo, Guan Chiap
Date of Issue2017-05-23
School of Mechanical and Aerospace Engineering
Wire drawing is a metal forming operation which involves pulling a metal rod or wire through the die or a converging channel to reduce the cross-sectional area and to increase the length with the volume of the material being constant. The wire drawing process is used to manufacture very fine wires used in medical applications such as in pacemakers. From the comparison of mechanical properties of materials suitable for medical usage, MP35N, a Co-Ni based super alloy is chosen as the material has the best combination of strength, ductility, resistance to corrosion and fracture . Therefore, there is a need to understand best drawing practice of drawing the MP35N wires. To find the best drawing practice, finite element analysis will be done using Ansys 16.0 and Abaqus FEA software to find out the effective stresses and plastic strains experienced by the wires. The process variables to be compared in this study includes the type of drawing practice, Full Die Drawing (FDD) and Half Die Drawing (HDD), and the die reduction angle, α. The best drawing practice and optimum die reduction angle is determined by having the least stress and strain experienced by the wire. Furthermore, the stress and strain distribution should be uniform throughout the whole section of the wire to ensure homogenous deformation. In the first part of the simulation, the two drawing practices are used to find out the effects on the effective stress and plastic strain and their distribution. In the second part of the simulation, different reduction angles are used to find out the its effects on the stress and strain. To support the simulation results done using Ansys 16.0 and Abaqus FEA software, an experimental micro hardness indentation test is done to correlate the test results with the simulation results. The results of the simulations and experimental results are that using FDD process at a optimum reduction angle of α = 8° will ensure the wires drawn experience more homogeneous deformation.
Final Year Project (FYP)
Nanyang Technological University