Investigation of Deformation Behavior for Commercially Pure Titanium Grade 2 Through Continuous Forming Process

Abstract

In this study, the investigation of deformation behavior for CP-Titanium grade 2 feedstock materials through Continuous Forming process was carried out. The theoretical analysis, numerical simulation and experimental validation, including testing and characterization of the feedstock before and after deformation were carried out. The theoretical analysis was carried out through Upper Bound Method. The numerical simulation was carried out through the three-dimensional finite element tool DEFORM-3D. The experimental plan and design was carried out using Taguchi (2^3) array methods in MINTAB platform by considering extrusion wheel velocity and feedstock temperature as chief extrusion parameters. The experimental analysis and validation of numerical results were carried out by extrusion forming of 12.5 mm CP- Titanium grade 2 feedstock materials using TBJ350 CONFORM machine setup. The optimization process of parameters for optimum value of response variables were carried out through Grey Relational Analysis. The special case study for optimization of effective stress for Titanium grade 5 feedstock materials was also carried out using Response Surface Methodology. The 12.5 mm diameter feedstock rod was extruded to 10 mm, 8 mm and 6 mm rod. It was observed that the power consumption for 6 mm extruded rod through Upper Bound technology, DEFORM-3D and experimentation was 45.48 kW, 47.75 kW and 50.13 kW respectively. Therefore, the numerical results were found to be in full agreement with the theoretical and experimental results, thereby maintaining the error up to 5 %. The numerical results reveals that the effective-stress of feedstock material was high in the biting-deformation region and then gradually decreases towards the flowing direction of the material. It was found that the optimum values of extrusion wheel velocity and feedstock temperature during continuous forming process for target value of 500 MPa were 16 RPM and 398.5 0C. It was observed that as the feedstock temperature increases, the value of effective stresses which occur in other region decreases to some extent. So, the results declared that increasing extrusion wheel velocity and feedstock temperature of material will reduce the shear strength of feedstock material during the continuous forming process. Therefore, the load requirement for deformation can be reduced. Moreover, the wear of extrusion shoe which is one of the most important elements can also be minimized thereby the life of extrusion shoe material can be enhanced. From the hardness test, it was observed that the hardness of the extruded feedstock of 6 mm diameter was 242.8 VHN which was improved by 67.45 % when compared with the raw feedstock material. The increment in the tensile strength was observed after deformation of the feedstock material (83.14% for 6 mm rod, 71.51 % for 8 mm rod and 40.98 % for 10 mm rod). The optical microscopy reveals that the grain refinement was achieved after deformation of the feedstock material. The Grey Relational Analysis reveals that the optimum values of effective stresses and power consumption was found to be at 8 RPM as the wheel velocity and 200 0C as the feedstock temperature. The proposed thesis will be helpful for the metal forming industries working in this area where titanium products strength can be enhanced

In This Study, The Investigation Of Deformation Behavior For Cp-Titanium Grade 2 Feedstock Materials Through Continuous Forming Process Was Carried Out. The Theoretical Analysis ,Numerical Simulation And Experimental Validation, Including Testing And Characterization Of The Feedstock Before And After Deformation Were Carried Out. The Theoretical Analysis Was Carried Out Through Upper Bound Method. The Numerical Simulation Was Carried Out Through The Three-Dimensional Finite Element Tool Deform-3d. The Experimental Plan And Design Was Carried Out Using Taguchi (2^3) Array Methods In Mintab Platform By Considering Extrusion Wheel Velocity And Feedstock Temperature As Chief Extrusion Parameters. The Experimental Analysis And Validation Of Numerical Results Were Carried Out By Extrusion Forming Of 12.5 Mm Cp- Titanium Grade 2 Feedstock Materials Using Tbj350 Conform Machine Setup. The Optimization Process Of Parameters For Optimum Value Of Response Variables Were Carried Out Through Grey Relational Analysis. The Special Case Study For Optimization Of Effective Stress For Titanium Grade 5 Feedstock Materials Was Also Carried Out Using Response Surface Methodology. The 12.5 Mm Diameter Feedstock Rod Was Extruded To 10 Mm, 8 Mm And 6 Mm Rod. It Was Observed That The Power Consumption For 6 Mm Extruded Rod Through Upper Bound Technology, Deform-3d And Experimentation Was 45.48 Kw, 47.75 Kw And 50.13 Kw Respectively. Therefore, The Numerical Results Were Found To Be In Full Agreement With The Theoretical And Experimental Results, Thereby Maintaining The Error Up To 5 %. The Numerical Results Reveals That The Effective-Stress Of Feedstock Material Was High In The Biting-Deformation Region And Then Gradually Decreases Towards The Flowing Direction Of The Material. It Was Found That The Optimum Values Of Extrusion Wheel Velocity And Feedstock Temperature During Continuous Forming Process For Target Value Of 500 Mpa Were 16 Rpm And 398.5 0c. It Was Observed That As The Feedstock Temperature Increases, The Value Of Effective Stresses Which Occur In Other Region Decreases To Some Extent. So, The Results Declared That Increasing Extrusion Wheel Velocity And Feedstock Temperature Of Material Will Reduce The Shear Strength Of Feedstock Material During The Continuous Forming Process. Therefore, The Load Requirement For Deformation Can Be Reduced. Moreover, The Wear Of Extrusion Shoe Which Is One Of The Most Important Elements Can Also Be Minimized Thereby The Life Of Extrusion Shoe Material Can Be Enhanced. From The Hardness Test, It Was Observed That The Hardness Of The Extruded Feedstock Of 6 Mm Diameter Was 242.8 Vhn Which Was Improved By 67.45 % When Compared With The Raw Feedstock Material. The Increment In The Tensile Strength Was Observed After Deformation Of The Feedstock Material (83.14% For 6 Mm Rod, 71.51 % For 8 Mm Rod And 40.98 % For 10 Mm Rod). The Optical Microscopy Reveals That The Grain Refinement Was Achieved After Deformation Of The Feedstock Material. The Grey Relational Analysis Reveals That The Optimum Values Of Effective Stresses And Power Consumption Was Found To Be At 8 Rpm As The Wheel Velocity And 200 0c As The Feedstock Temperature. The Proposed Thesis Will Be Helpful For The Metal Forming Industries Working In This Area Where Titanium Products Strength Can Be Enhanced