VIETNAM NATIONAL UNIVERSITY HO CHI MINH CITY HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY TRA NGOC TIEN DAT INVESTIGATION ON THE EFFECT OF PIN PROFILE ON TENSILE STRENGTH OF FRICTION STIR WELDING Major Subject: Engineering Mechanics Codes: 8520101 MASTER THESIS HO CHI MINH CITY, January 2023 THIS RESEARCH IS COMPLETED AT HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY – VNU HCM Instructor: Ass. PhD Vu Cong Hoa PhD. Duong Dinh Hao Examiner 1: PhD. Mai Duc Dai Examiner 2: PhD.
Nguyen Tuong Long Master’s thesis is defended at HCMC University of Technology, VNU HCM on January 11, 2023. The Board of Master’s thesis defense council includes: 1. PhD Ngo Kieu Nhi 2. Pham Bao Toan 3.
Counter-Argument member 1: PhD. Mai Duc Dai 4. Counter-Argument member 2: PhD. Pham Tan Hung 5.
Council Member: PhD. Nguyen Tuong Long Verification of the chairman of the master’s thesis defense council and the Dean of the Faculty of Applied Science after the thesis is correct (if any). DEAN OF FACULTY OF CHAIRMAN OF THE COUNCIL APPLIED SCIENCE (Full name and signature) (Full name and signature) i VIETNAM NATIONAL UNIVERSITY HCMC SOCIALIST REPULIC OF VIETNAM VNUHCM UNIVERSITY OF TECHNOLOGY Independent – Liberty – Happiness MASTER’S THESIS ASSIGNMENTS Full name: Tra Ngoc Tien Dat Leaner ID: 2070067 Date of birth: 10/10/1997 Place of birth: Quang Ngai Major: Engineering mechanics Major ID: 8520101 I. TITLE: INVESTIGATION ON THE EFFECT OF PIN PROFILE ON TENSILE STRENGTH OF FRICTION STIR WELDING/ KHẢO SÁT ẢNH HƯỞNG BIÊN DẠNG CHỐT HÀN ĐẾN ĐỘ BỀN KÉO MỐI HÀN MA SÁT KHUẤY II.
ASSIGMENTs: - Research about the principle of friction stir welding process. - Design and fabricate friction stir welding tools with different pin profile. - Initialize the simulation model for friction stir welding process in Abaqus software. - Conduct the friction stir welding experiment with aluminum alloy AA6061- T6.
- Evaluate and analyze the effect of pin profiles on the tensile strength of the welds and other mechanical properties. ASSIGMENT DELIVERY DATE: September 05, 2022 IV. ASSIGMENT COMPLETING DATE: December 18, 2022 V. PhD VU CONG HOA PhD DUONG DINH HAO Ho Chi Minh City, January 11, 2023 INSTRUCTOR 1 INSTRUCTOR 2 (Full name and signature) (Full name and signature) Ass.
PhD Vu Cong Hoa PhD. Duong Dinh Hao ii HEAD OF DEPARTMENT DEAN OF FACULTY (Full name and signature) (Full name and signature) Ass. PhD Vu Cong Hoa. PhD Truong Tich Thien iii LỜI CẢM ƠN Lời đầu tiên, tôi xin chân thành cảm ơn đến hai người thầy đã hướng dẫn tôi trong luận văn này là PGS TS Vũ Công Hoà và TS Dương Đình Hảo.
Cảm ơn hai thầy đã cho tôi những định hướng, phương pháp nghiên cứu, cũng như sự hỗ trợ hết sức nhiệt tình trong suốt thời gian thực hiện đề tài. Tôi cũng xin gửi lời cảm ơn đến: - Bộ môn Cơ kỹ thuật, khoa Khoa học ứng dụng, trường Đại học Bách Khoa TP. HCM đã cung cấp những kiến thức và kinh nghiệm trong thời gian 2 năm tôi theo học tại đây. TS Trần Hưng Trà và phòng thí nghiệm Hàn ma sát khuấy, trường Đại học Nha Trang, đã hỗ trợ trong việc thực hiện thí nghiệm hàn, cũng như việc đánh giá chất lượng mối hàn.
- Những đồng nghiệp, bạn bè ở Khoa Cơ khí, cũng như trường Đại học Bách Khoa, đã hỗ trợ trong việc thiết kế, chế tạo các chốt hàn. Cuối cùng, xin gửi lời cảm ơn đén gia đình, người thân, đã luôn đồng hành, hỗ trợ tôi trong suốt thời gian qua. Người thực hiện Trà Ngọc Tiến Đạt iv ABSTRACT Friction stir welding is now widely applied in material joining applications, in many fields such as aerospace, marine, railway. In this method, tool pin profile has great impact on the quality of the weld.
This study will present the investigation on the effect of different pin profiles on the quality of FSW joint, particularly in tensile strength. The numerical model is developed with Coupled Eulerian Lagrangian technique in Abaqus software. The heat generation is validated by experimental work. The evaluation of mechanical properties of the weld, including tensile strength, bending strength and hardness was performed.
The macrostructure and microstructure analysis were also conducted. As a result, FSW joint had been successful made in which investigated tools with joint efficiency around 78%. However, the effect of different tool pin profiles on the tensile strength is not clearly observed. The numerical model is good for prediction the temperature distribution in FSW process with a quite accuracy compared with experimental results.
v TÓM TẮT LUẬN VĂN THẠC SĨ Hàn ma sát khuấy ngày càng được áp dụng rộng rãi trong ứng dụng hàn hay kết nối vật liệu với nhau, ứng dụng trong các ngành hàng không, vũ trụ, tàu thuỷ, … Trong phương pháp hàn ma sát, biên dạng chốt hàn đóng vai trò quan trọng trong việc tạo ra một mối hàn đạt chất lượng. Luận văn này sẽ trình bày khảo sát ảnh hưởng của các biên dạng chốt hàn khác nhau lên chất lượng của mối hàn ma sát, cụ thể là độ bền kéo. Mô hình mô phỏng số cũng được xây dựng bằng phần mềm Abaqus, sử dụng kỹ thuật mô hình hoá Coupled Eulerian Lagrangian. Sự sinh nhiệt trong quá trình hàn, sẽ được kiểm tra bằng kết quả thí nghiệm.
Cơ tính mối hàn, gồm độ bền kéo, độ bền uốn và độ cứng mối hàn được đánh giá. Việc khảo sát cấu trúc thô đại và cấu trúc tế vi của mối hàn cũng đã được thực hiện. Với các biên dạng đầu hàn dùng trong khảo sát này, các mối hàn ma sát khuấy đã được tạo ra với chất lượng đạt yêu cầu, với hiệu suất hàn khoảng 78%. Tuy nhiên, ảnh hưởng của các biên dạng chốt hàn khác nhau chưa được thấy rõ.
Mô hình mô phỏng đã cho ra sự phân bố nhiệt độ trong quá trình hàn ma sát khuấy với độ tin cậy cao. vi GUARANTEE I hereby declare that the master’s thesis, “Investigation on The Effect of Pin Profile on Tensile Strength of Friction Stir Welding” is my independent scientific study. The numerical and experimental data in this thesis was conducted based on my effort, with strong support from Assoc. Vu Cong Hoa and Dr.
Duong Dinh Hao. All references have been clearly cited. The research data in the topic is honest and absolutely not copy or use the results of other research topics. If there is a copy found, I will fully assume all responsibility.
Author Tra Ngoc Tien Dat vii CONTENT CONTENT. vii List of Figures .x List of Tables. Work Plan and Objectives:. Organization of the Thesis.
Fundamentals of Friction Stir Welding. Heat Generation in Friction Stir Welding. Friction Stir Welding Tool. Coupled Eulerian Lagrangian Formulation.
Lagrangian and Eulerian Analysis [13]. Using Coupled Eulerian – Lagrangian Formulation in FSW. Evaluation of FSW Weld Properties. FSW Quality-related Parameters.
Tool Pin Profile Design. Contact Interaction and Boundary Conditions. Mass Scaling Technique. Fabrication of FSWed butt-joint.
Tensile and bending test. RESULT AND DISCUSSION. Numerical Model Validation. Inspection of the butt-joints.
Tensile Strength Testing Result. Bend Testing Result. CONCLUSION AND FUTURE WORK. Summary the Results.
Recommendation for Future Work .54 APPENDIX A - Al6061_T6 Material Certification.56 APPENDIX B – FSW Tool Drawing .57 x List of Figures Figure 2-1 A schematic drawing of friction stir welding in a butt joint configuration .6 Figure 2-2 Typical conventional FSW transverse section in 25.4-mm thick 2195 aluminum-lithium plate.8 Figure 2-3 Schematic of FSW process.8 Figure 2-4 Image courtesy of Stirweld company.10 Figure 2-5 Shoulder geometries [10] .11 Figure 2-6 FSW Pin Profiles .12 Figure 2-7 DOE FSW Process schematic .16 Figure 2-8 Specimen dimension for tensile testing.17 Figure 2-9 3-point flexure test [19] .17 Figure 3-1 Investigated tool pin profiles .18 Figure 3-2 Tool and workpiece assembly with void and material assigned regions.19 Figure 3-3 Eulerian Mesh (Workpiece) .21 Figure 3-4 Velocity boundary conditions on the workpiece .23 Figure 4-1 Aluminum plates before welding.26 Figure 4-2 Fabricated FSW Tools.27 Figure 4-3 Mazak V500 machine .28 Figure 4-4 Overview of fabricating FSWed butt-joint.28 Figure 4-5 Image of FSW process.29 Figure 4-6 Temperature measurement equipment: (a) Datalogger; (b) Thermocouple type K .29 Figure 4-7 Microstructure analysis equipment.30 Figure 4-8 Hardness measurement in Nha Trang University .30 Figure 4-9 Cutting layout for testing specimens.31 Figure 4-10 Tensile strength testing specimens.31 Figure 4-11 Specimens for bend testing.32 Figure 4-12 Tensile testing process .32 xi Figure 4-13 Bending testing process .32 Figure 5-1 Temperature recording position.33 Figure 5-2 Heat generation - Tool 1.33 Figure 5-3 Heat generation - Tool 2.34 Figure 5-4 Heat generation - Tool 3.34 Figure 5-5 Heat generation - Tool 4.35 Figure 5-6 Modeling of the temperature distribution at 31s (a) Tool 1, (b) Tool 2, (c) Tool 3, (d) Tool 4 .36 Figure 5-7 Modeling of the temperature distribution at 31s (a) Tool 1, (b) Tool 2, (c) Tool 3, (d) Tool 4 .36 Figure 5-8 Modeling of the temperature distribution at 60s (a) Tool 1, (b) Tool 2, (c) Tool 3, (d) Tool 4 .37 Figure 5-9 Temperature distribution along the cross-section at the end of plunging phase (step time: 31s) .37 Figure 5-10 Experimental result and FEM result comparison.38 Figure 5-11 A finished FSW joint .40 Figure 5-12 Face of the welds .41 Figure 5-13 Root of the welds.41 Figure 5-14 Macrostructure of cross-section of the welds .42 Figure 5-15 Representative microstructures of cross-section of specimen produced by Tool 3. (a) Cross-section macrostructure; (b) Microstructure of Base metal zone; (c) Microstructure of Stir zone; (d) Microstructure of Thermal-mechanically affected zone; (e) Microstructure of Heat affected zone.42 Figure 5-16 Comparison in microstructure at SZ and HAZ produced by various tools.43 Figure 5-17 Hardness distribution measured along center weld at various tools.44 Figure 5-18 Stress-strain curve of specimens produced by various tools.45 Figure 5-19 Fracture position of tested specimens (welded by Tool 1) .45 Figure 5-20 Fracture position of tested specimens (welded by Tool 2) .46 Figure 5-21 Fracture position of tested specimens (welded by Tool 3) .46 xii Figure 5-22 Fracture position of tested specimens (welded by Tool 4) .46 Figure 5-23 Tensile strength property comparison and joint efficiency of the welds.47 Figure 5-24 After bending specimens - Face bend .48 Figure 5-25 After bending specimens – Root bend .48 Figure 5-26 Force – Displacement Bending Curve of Tool 1 .49 Figure 5-27 Force – Displacement Bending Curve of Tool 2 .49 Figure 5-28 Force – Displacement Bending Curve of Tool 3 .50 Figure 5-29 Force – Displacement Bending Curve of Tool 4 .50 Figure 5-30 Bending properties of FSW joints with 4 pin profiles.51 xiii List of Tables Table 1 Dynamic/static volume of tool pin profiles.18 Table 2 Constants used in the Johnson Cook material model [21] .20 Table 3 Variation of the physical properties of AA6061-T6 with temperature [20] 20 Table 4 H13 steel properties [22] .21 Table 5 Chemical composition of AA6061-T6 (mass percentage) .26 Table 6 Mechanical properties of AA6061-T6 .26 Table 7 Mazak V550 specifications .27 Table 8 Numerical and experimental result of temperature .38 Table 9 Tensile strength test results (in MPa).47 Table 10 Bend testing results (in MPa) .51 xiv Glossary of Term FSW – Friction Stir Welding CEL – Coupled Eulerian – Lagrangian AA – Alloy Aluminum HAZ – Heat-affected zone TMAZ – Thermal-mechanically affected zone BM – Base metal SZ – Stirring zone MZ – Mix zone EVF – Eulerian Volume Fraction L – Length W – Width T – Thickness 1 CHAPTER 1. Background Metals joining processes can be divided into four basis categories: fusion welding; brazing and soldering; adhesive bonding; and solid-state bonding.
