Experimental surface treatment using arc welding application for flat products

MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH QUALITY TRAINING CAPSTONE PROJECT ELECTRONICS AND TELECOMMUNICATIONS ENGINEERING TECHNOLOGY EXPERIMENTAL SURFACE TREATMENT USING ARC WELDING – APPLICATION FOR FLAT PRODUCTS LECTURER: PhD PHẠM SƠN MINH STUDENT: NGUYỄN VĂN TẤN TRẦN NGUYỄN ANH TÀI NGUYỄN TUẤN KIỆT SKL010888 Ho Chi Minh City, 2023 MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH QUALITY TRAINING MECHANICAL ENGINEERING TECHNOLOGY GRADUATION THESIS EXPERIMENTAL SURFACE TREATMENT USING ARC WELDING - APPLICATION FOR FLAT PRODUCTS ADVISER: Associate Professor, PhD PHẠM SƠN MINH STUDENTS: NGUYỄN VĂN TẤN 18144050 TRẦN NGUYỄN ANH TÀI 19144333 NGUYỄN TUẤN KIỆT 19144088 Ho Chi Minh City, July 2023 SOCICALIST REPUBLIC OF VIETNAMĐộc Independent - Freedom – Happiness HCM University of Technology and Education FACULTY FOR HIGH QUALITY TRAINING GRADUATION THESIS MISSIONS Semester 2/ Year: 2023 Adviser: Associate Professor, PhD Phạm Sơn Minh Students: Nguyễn Văn Tấn MSSV: 18144050 TEL: 0857252733 Trần Nguyễn Anh Tài MSSV: 19144333 TEL:0968546213 Nguyễn Tuấn Kiệt MSSV: 19144088 TEL: 0948920139 Name of topic: Experimental Surface Treatment Using Arc Welding - Application for Flat Products Initial Data and Documents: - Distance from stungsten to surface - Velocity - Alternating current - Shielding gas Main Content of the Project: Improving surface hardness, microhardness, and microstructure alterations Expected Deliverables - Realistic product model - Analytical report Date assigned to the project: March 15, 2023 The deadline for project submission: July 15, 2023 Presentation language: The report: English  Vietnamese  Protection presentation: English  Vietnamese  HEAD OF DEPARTMENT TRSENIOR MANAGER ADVISER (Sign, write full name) (Sign, write full name) (Sign, write full name) HCM University of Technology and Education SOCIALIST REPUBLIC VIETNAM FALCULTY FOR HIGH QUALITY TRAINING Independent – Freedom – Happiness COMMENTS FORGRADUATION PROJECT (For adviser) Full name of the students: Nguyễn Văn Tấn MSSV: 18144050 Trần Nguyễn Anh Tài MSSV: 19144333 Nguyễn Tuấn Kiệt MSSV: 19144088 Project name : Experimental Surface Treatment Using Arc Welding - Application for Flat Products Major: Mechanical Engineering Technology Adviser: Associate Professor, PhD Phạm Sơn Minh COMMENTS Comments on the student's spirit and working attitude: Evaluation of the execution results of the Graduation Thesis: 2.1 Structure, how to present the graduation thesis: 2.2 Content of the thesis: (Theoretical foundation, practicality, and applicability of the thesis, potential areas for further research) 2.3 Achieved results: 2.4 Existing shortcomings (if any): Rating: No Reviews section Maximum score Points earned Graduation project form and structure 30 Correct format with full form and content of entries 10 Objectives, tasks, overview of the topic 10 The urgency of the subject 10 Contents of Graduation Project 50 Ability to apply knowledge of mathematics, science and engineering, social sciences Ability to perform / analyze / synthesize / evaluate 10 The ability to design and manufacture a system, component, or process that meets a given requirement with realistic constraints 15 Ability to improve and develop 15 Ability to use technical tools, specialized software Evaluate the applicability of the topic 10 Specific products of the Graduation Project 10 Total score 100 Conclusion  Permission to present graduation project  Graduation project present is not allowed Ho Chi Minh City, July 2023 ADVISER (Sign and write your first and last name) THANK YOU NOTE We would like to express our sincere gratitude to the teachers of Ho Chi Minh City University of Technology and Education who have supported and assisted us throughout the process of completing our graduation project on the topic "Experimental Surface Tempering Treatment Using Energy from Arc Welding - Application for Flat Products." First and foremost, we want to express our appreciation to the teachers, providing the necessary knowledge and skills to us, enabling us to accomplish this project This knowledge not only helped us grasp the theory but also supported us in conducting experiments and analyzing data We would also like to extend our appreciation to Associate Professor Pham Son Minh, Mr Tran Minh The Uyen, Mr Nguyen Van Thuc, Mr Truong Thanh Cong, and Mr Nguyen Van Mang for providing us with the essential materials and equipment for conducting the experiments Thanks to them, we can perform experiments accurately and reliably Besides, we would like to sincerely thank the guidance, and dedicated help of the teachers during the implementation of the project The input and contributions from the teachers have greatly helped us enhance the quality of our research Once again, we would like to express our profound gratitude to the teachers of Ho Chi Minh City University of Technology and Education who have assisted us during this graduation project We hope that this project will yield positive results and provide valuable information to the metal production industry regarding the surface treatment process using plasma energy to achieve the optimal hardness and microstructure of C45 steel samples ABSTRACT EXPERIMENTAL SURFACE TREATMENT USING ARC WELDING APPLICATION FOR FLAT PRODUCTS In recent years, the use of plasma energy for surface treatment of metals has become very important option in the manufacturing industry This is because this method allows for significant improvement in the surface properties of metal products, including both durability and hardness Among these properties, surface hardness and microstructure play a crucial role in ensuring the mechanical properties of the products This technique is one of the most advanced methods to enhance the mechanical properties of steel The process of surface treatment using arc welding involves the interaction between light and the metal surface Arc is emitted from a Arc source and melted the metal surface The energy of the arc welding is absorbed by the steel surface, resulting in radiation and thermal emission, raising the surface temperature Subsequently, the metal surface is rapidly cooled through fast cooling methods to create the best crystal structure on the metal surface When the hardness of C45 steel is increased using this method, the impacts on the metal surface are also significantly reduced This is particularly important in increasing the lifespan and durability of metal products However, to achieve optimal efficiency, the surface treatment process using plasma energy needs to be designed and adjusted with specific parameters, including current intensity, machine speed, and distance between the metal surface and the light source Optimizing these parameters is crucial to achieving the best mechanical properties of C45 steel after surface treatment using arc energy TABLE OF CONTENTS GRADUATION THESIS MISSIONS…………………………………………………… COMMENTS FORGRADUATION PROJECT………………………………………………3 CHAPTER 14 INTRODUCTION 14 1.1.Problem Statement 14 1.2.Research Status in Vietnam 14 1.3.Research Status Overseas 15 1.4.Objectives of the topic 15 1.5.Research subjects and scope 15 1.5.1 Research subjects 15 1.5.2 Research scope 15 1.6.Research methods 16 1.6.1 Theoretical research 16 1.6.2 Experimental research 16 1.7.Scientific and practical significance of the topic 16 1.7.1 Scientific significance 16 1.7.2 Practical Significance 17 1.8.Limitations of the Topic 17 1.9.Project structure 17 CHAPTER 18 THEORETICAL BASIS 18 2.1 Overview of TIG Welding 18 2.2 Classification of TIG Welding 18 2.3 Experiment of Surface Fusion Energy Welding - Flat Surface 19 2.3.1 Post-TIG Welding Processing of Products 21 2.3.2 Some Materials Used in TIG Welding 21 2.4 Shielded Gas Tungsten Arc Welding 22 2.4.1 Overview of Shielded Gas Tungsten Arc Welding 22 2.4.2 Characteristics of TIG Welding 23 2.4.3 Advantages and Disadvantages of TIG Welding 24 2.4.4 Welding Materials and Equipment 24 2.4.4.1 Welding Materials 24 2.4.4.2 Welding Equipment 31 2.4.5 Metal Droplet Transfer Modes in TIG Welding 33 2.4.5.1 Line Transfer 33 2.4.5.2 Globular Transfer 34 2.4.5.3 Backstepping Motion 34 2.4.5.4 Synchronous Motion 35 2.4.6 Welding Parameters 35 CHAPTER 39 UNDERSTANDING, RESEARCHING, AND FABRICATING WELDING SAMPLES 39 3.1 Selecting the Welding Material 39 3.2 Selecting the Size of the C45 Steel Sample 40 3.3 Surface Milling of C45 Steel Before Welding 40 3.4 Selecting the Necessary Data for the Taguchi Welding Process 41 3.5 Welding Sample Fabrication Process 44 3.5.1 Preparation of Tools and Equipment 44 3.5.2 Simulation of Welding Paths on CNC Machines 45 3.6 Key Processes to Ensure Beautiful Welds 46 3.7 Welding Samples 48 CHAPTER 51 SAMPLE FABRICATION, MEASUREMENT METHODS, MEASUREMENT DATA, AND EXPERIMENTAL DATA PROCESSING 51 4.1 Experimental sample 51 4.1.1 Dimensions 51 4.1.2 Material 51 4.1.3 Crystal lattice 51 4.2 Double-sided milling and the purpose of double-sided milling operation 52 4.2.1 Flattening and aligning the surface 52 4.2.2 Increasing the adhesion layer 52 4.3 Surface treatment using laser energy 52 4.4 Experimental data 53 4.4.1 Taguchi experimental data 53 CHAPTER 55 EXPERIMENTAL RESULTS 55 5.6 Measurement data of experimental samples by using univariate method Table 5.1: Measurement data of experimental samples by using univariate method Sample Z I V G Surface hardness (mm) (A) (mm/min) (L/min) (HV) 0.5 248 308 1.5 2.5 50 388 363 284 80 75 294 100 125 150 303 10 175 303 405 363 11 100 331 12 120 362 140 388 160 375 180 363 13 1.5 14 15 100 16 294 11 388 14 331 19 17 303 20 20 303 17 18 140 Z: Distance from the tungsten electrode to the metal surface (mm) I: Alternating current (A) V: Velocity (mm/min) G: Shielding gass (L/min) 59 Table 4.3 shows the variation of parameter Z in increments with a step size of 0.5, while keeping the other parameters (A, V, G) constant Then, the surface hardness was measured and sample number was obtained with the highest hardness value of 388, corresponding to the following parameter set: Z: 1.5; A: 50; V: 50; G: Taking the parameter set of sample number 3, the parameter A was varied in increments with an increasing trend while keeping the other parameters (Z, V, G) constant Then, the surface hardness was measured, and sample number was obtained with the highest hardness value of 405, corresponding to the following parameter set: Z: 1.5; A: 80; V: 50; G: Taking the parameter set of sample number 7, the parameter V was varied in increments with an increasing trend while keeping the other parameters (Z, A, G) constant Then, the surface hardness was measured, and sample number 13 was obtained with the highest hardness value of 388, corresponding to the following parameter set: Z: 1.5; A: 80; V: 120; G: Zmax = 2.5 Z Zmin = 0.5 Figure 5.7: Univariate method 60 5.7 Relationship between Distance from the tungsten electrode to the metal surface and hardness Figure 5.8: Relationship between Z and hardness Figure 5.8 depicts the relationship between Z and hardness, where the maximum hardness value is 388 with the parameter set Z: 1.5; A: 50; V: 50; G: Additionally, the minimum hardness value is 248 with the parameter set Z: 0.5; A: 50; V: 80; G: 61 5.8 Relationship between amperage and hardness Figure 5.9: Relationship between amperage and hardness Figure 5.9 Shows the relationship between alternating current and hardness, where the maximum hardness value is 405 with the parameter set Z: 1.5; A: 100; V: 80; G: On the other hand, the minimum hardness values are 303 with the parameter sets Z: 0.5; A: 175; V: 80; G: and Z: 1.5; A: 175; V: 80; G: 62 5.9 Relationship between velocity and hardness Figure 5.10: Relationship between velocity and hardness Figure 5.10 illustrates the relationship between velocity and hardness, where the maximum hardness value is 388 (HV) with the parameter set Z: 1.5; A: 100; V: 140; G: Furthermore, the minimum hardness value is 331 (HV) with the parameter set Z: 1.5; A: 100; V: 100; G: 63 5.10 Relationship between shielding gas and hardness Figure 5.11: Relationship between shielding gas and hardness Figure 5.11 Shows the relationship between shielding gas and hardness, where the maximum hardness value is 388 (HV) with the parameter set Z: 1.5; A: 100; V: 140; G: Furthermore, the minimum hardness value is 303 (HV) with the parameter set Z: 1.5; A: 100; V: 100; G: 20 and Z: 1.5; A: 100; V: 100; G: 17 64 5.11.Hardness values, HV0.3 Table 5.2: Microhardness value Depth to the surface, µm Hardness values, HV0.3 Sample 18 Sample 100 364 427 200 355 402 300 350 381 400 357 451 500 382 408 600 330 408 700 352 412 800 359 422 900 365 372 1000 364 372 1100 343 368 1200 321 406 1300 346 379 1400 378 359 1500 376 383 1600 300 394 1700 325 381 1800 328 286 1900 359 295 2000 283 210 2100 288 197 2200 311 201 2300 292 180 2400 310 167 2500 293 167 65 5.12 The distribution of microhardness in the thickness for steels sample 18 THE DISTRIBUTION OF MIRCOHARDNESS IN THE THICKNESS STEELS SAMPLE 18 450 MIRCOHARDNESS (HV) 400 350 364 355 350 357 382 330 378 376 365 364 352 359 343 359 346 325 328 321 300 300 311 283 288 292 310 293 250 200 150 100 50 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 POSITION (µm) Axis Title Figure 5.12: The distribution of microhardness in the thickness for steel sample 18 The distribution of microhardness in the thickness for steel sample 18 shows an uneven trend of increase and decrease The highest microhardness value at position is 378HV at 400 µm, which is 2.7 times higher than the initial hardness of 139HV The lowest microhardness value is 292HV at a position of 2000 µm, which is times higher than the initial hardness of 139HV The distance from 400 µm to 2000 µm represents the center of the heat-affected zone, while the distance from 2000 µm to 2500 µm represents the position outside the heataffected zone Therefore, the microhardness values tend to decrease gradually The most affected position with the highest microhardness value is between 400 µm and 2000 µm 66 5.12.1 The distribution of microhardness in the thickness for steels sample THE DISTRIBUTION OF MIRCOHARDNESS IN THE THICKNESS STEELS SAMPLE 500 MIRCOHARDNESS (HV) 450 400 451 427 402 422 408 408 412 381 406 379 372 372 368 350 359 383 394 381 286 295 300 250 210 210 201 200 180 167 167 150 100 50 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 POSITION (µm) POSITION Figure 5.13: The distribution of microhardness in the thickness for steels sample The distribution of microhardness in the thickness for steels sample shows a consistent decreasing trend The highest microhardness value of sample is 451HV at a position of 400 µm, which is 3.3 times higher than the initial hardness of 139HV The lowest microhardness value is 167HV at a position of 2500 µm, which is 1.2 times higher than the initial hardness of 139HV The distance from 400 µm to 1700 µm represents the center of the heat-affected zone, while the distance from 1700 µm to 2500 µm represents the position outside the heataffected zone Therefore, the microhardness values tend to decrease gradually The most affected position with the highest microhardness value is between 400 µm and 1700 µm 67 5.13 Sample preparation and observation method: a) Rough grinding: After cutting, the sample will be roughed on sandpaper follow parallar size with the sandpaper Using different types of sandpaper from small to large, with higher numbers indicating finer grit sizes such as 180, 240, 320, 400, 600, etc Firstly, we use the rough grinding with 180 sandpaper The sandpaper is placed on the a thick glass plate, and the sample's surface is pressed on the sandpaper, moving it in a straight direction and with 20 times, Finally, the sample is rotated approximately 90 degrees and the grinding process is continued to remove old scratches and create new ones.and then we will use another sandpaper with another size, such as 240, 320, 400 This steps are very important to make sure that the surface of the sample is cleaned b) Polishing: After rough grinding process, our sample is still have fine scratches may be remained on the sample's surface So we need to use polishing machine with a polishing felt attached on top The sample is polished on this machine to remove the remaining scratches Figure 5.14: MP-2B Grinder Polisher During the polishing process, these small scratched will be removed The polishing solution consists of a mixture of Chromium oxide (Cr2O3) After polishing, the sample must be thoroughly rinsed and dried It should be observed under a microscope to check for any remaining scratches If necessary, additional polishing may be required c) Etching: Aftter polising process we come to the nex process that is etching Etching is known the process of selectively corroding the metal surface by using an appropriate chemicals Before etching, the sample's surface must be cleaned from scratches, rust, and impurities 68 d) Microscopic observation: The sample is observed under a microscope Figure 5.15: Microscope Procedure: Step 1: Plug in the power and turn on the light switch Step 2: Select the objective lens and eyepiece, and adjust the interpupillary distance Step 3: Place the sample on the stage where the light shines Step 4: Adjust the coarse focus knob and observe on the computer screen Step 5: Fine-tune the focus knob to observe the microstructure clearly 69 5.14 The microstructure organization of C45 steel after quenching Martensite phase Martensite phase (a) (b) Perlitic phase Ferritic phase (c) (d) Heat zone Center Of Heat Zone Weld penetration (e) (f) Figure 5.16 Grain morphology of the weld penetration and heat zone for (f), Higher magnification images show (d) and (e) perlitic and ferritic phases, (a), (b) and (c) martensitic phase and austenite phase 70 CHAPTER CONCLUSION Through the process of conducting the Graduation Thesis, the group has fulfilled the set requirements and synthesized them in this report following the correct format, both in terms of form and content, including urgency, objectives, tasks, and an overview of the topic In general, the content of the Graduation Thesis has addressed the main issues as follows: • Application of mathematical, scientific, and technical knowledge, as well as social sciences, demonstrated in the Experimental Surface Tempering Treatment Using Energy from Arc Welding - Application for Flat Products • Implementation, analysis, synthesis, and evaluation demonstrated in the application of the Taguchi method and univariate method in the heating process, thereby selecting the optimal set of parameters and constructing graphs showing the relationship between factors and hardness • Design, fabrication of a system, component, or process to meet the specified requirements with practical constraints demonstrated in the modification of the microstructure, improving hardness after quenching • Capability of improvement and development demonstrated in the extension to the processing of other surface types such as convex and concave surfaces • Ability to use technical tools, specialized software demonstrated in the use of Minitab, Excel software to build data and analyze the influence of factors on hardness through the Taguchi and univariate methods Following the completion of this topic, the achieved results can be applied in the post-processing of C45 steel to increase hardness and enhance its mechanical properties Finally, the process of carrying out the topic has achieved specific results as follows: • Establishment of an optimal set of parameters for the quenching process • Improvement in surface hardness and microstructure hardness after quenching • Modification of the microstructure after tempering 71 THE 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