Lesson 1 Introduction to Welding Technology. Contents

Transcription

1 Department of Engineering Design Lesson 1 Introduction to Welding Technology Professor Pedro Vilaça * * Contacts Address: P.O. Box 14200, FI Aalto, Finland Visiting address: Puumiehenkuja 3, Espoo pedro.vilaca@aalto.fi ; Skype: fsweldone February 2015 Contents Summary Definition of welding Introduction and scope of welding technology Historical milestones of welding technology and allied techniques Introduction to fusion welding processes Introduction to brasing/soldering processes Introduction to solid state welding processes with focus on friction based technology and applications Samples of advanced welding solutions Joining mechanisms governing welding technology Fundamental nomenclature Introduction to weldability concept 1 1

2 Learning Outcomes At the end of the seminar the student should be able to 1. To identify the multiphysical character of welding technology 2. To distinguish between fusion, brasing and solid state welding 3. To identify main historical milestones of welding technology 4. To identify main fusion welding processes 5. To identify main solid state welding processes 6. To classify the main joining mechanisms in welding technology 7. To describe the weldability concept 2 Questions for Lesson 1 Please answer 2 of the following 3: a) Give 10 samples of welding processes and for each one identify its nature in terms of i) fusion; ii) solid state or iii) brasing. b) Establish the main joining mechanisms governing fusion, solid state and brasing welding technology. c) Considering the weldability concept which are the main features characterizing a welding application? 3 2

3 What is? (def.) welding - A joining process that produces coalescence of materials by Applying energy: heating them to the welding temperature, with/without the application of pressure or by the application of pressure alone With/without the use of filler metal With/without the use of shielding gas 4 What is? Third-body region Liquid joining interface Mechanical Energy Cold pressure Fusion of a nugget in close die pressured zone Heat Energy Fusion with no pressure 5 3

4 What is? Fluid Mechanics Thermodynamics Physical / Chemical Power Sources Manual Skills Creativity and Art Material Science Innovation Where Science and Business Product Development Production Management Quality Systems Computational Modeling meet Technology Automation and Robotization Electrical Equipment Electronic Control Structural Mechanics 6 Welding Technology The Scope Science Application Welding is not.. Fundamental Science Welding is not Practical Application 7 4

5 Welding Technology The Scope Among other joining technologies Adhesive Technology (e.g.: epoxy; polyurethane...) Technologies for Joining of Materials Mechanical Joints Threaded Riveting Clinching Welding 8 Introduction to Welding Hybrid Concepts Are Becoming Frequent Solutions e.g.: weld bonding adhesive spot welding rivet adhesive Threaded stud nut adhesive Stud weld 9 5

6 Introduction to Welding Related Technology Thermal Spraying Techniques (def.) Coating processes in which melted /heated materials are sprayed onto a surface Plasma spraying (PSP) Arc spraying (ASP) Flame spraying (FLSP) P atm Vacuum Thermal spraying can provide thick coatings [20 m.. to several mm], over a large area at high deposition rate as compared to other coating processes such as: electroplating, physical and chemical vapor deposition 10 Introduction to Welding Related Technology Cutting Techniques Mechanical cutting Thermal cutting Water jet cutting 11 6

7 Introduction to Welding Related Technology NDT Techniques 12 Solid State Welding Classification Fusion Welding Includes partial fusion of Base Material, with /without application of pressure, with/without filler metal added to weld pool Welding Process Classification Note: There are (many) others possible classifications Brazing and Soldering No fusion of base material components which are joined by inserting melted filler metal in the overlap joint configuration Solid State Welding Joining is obtained by solid state joining mechanisms In some processes, superficial melting layer is produced to then be expelled during forging Flash around weld zone is usual 13 7

8 Forging Forging Solid State Welding Prior to all Fusion Welding Techniques 14 Solid State Welding From the Origins into the Most Developed Modern Solutions 15 8

9 Forging Fusion Welding Electric Arc Based Welding Overview of Techniques 16 Fusion Welding Technology Historical Development 1980 Bare electrode SAW 1950 FCAW 1970 Electric Arc Coal electrode 1881 Oxifuel 1903 SMAW 1904 GTAW 1940 Welding Thermal Treat. Brasing EBW 1958 GMAW Electro-slag Electro-gas 1950 Plasma PAW Vacuum P atm 1959 Sinergic CMT Micro Conventional Keyhole Laser 1970 Thermite CO 2 Nd-YAG Excimers Diodes Fiber Disc 17 9

10 Milestones of Electric Arc Welding (1/4) Shielded Metal Arc Welding 18 Milestones of Electric Arc Welding (2/4) Submerged Arc Welding 19 10

11 Milestones of Electric Arc Welding (3/4) Gas Tungsten Arc Welding 20 Milestones of Electric Arc Welding (4/4) Gas Metal Arc Welding 21 11

12 Variants of GMAW Flux Cored Arc Welding 22 Fusion Welding Laser Welding Overview of Fundaments 23 12

13 Characteristics of a Laser Beam Light Amplificatio n Stimulated Emission Radiation Laser Welding 24 Wavelength of main active laser media Ultraviolet (0.1 m 0.4 m) Visible (0.4 m 0.7 m) Infrared (0.7 m 100 m) 25 13

14 Robotic Style Beam Delivery 26 Continuous Wave Laser Welding Applications 27 14

15 Fusion Welding Electron Beam Welding Overview of Fundaments 28 Generation Acceleration Focusing Guidance Working zone Simplified Representation of a Triode Electron Beam Gun Column 29 15

16 Equipment: Level of Vacuum in Gun and Working Cameras Variants: High-Vacuum: 10-3 to 10-6 Torr Fine-Vacuum: 25 to 10-3 Torr Non-vacuum (1 atm 760 Torr) High-vacuum chamber equipment for EBW 30 Equipment: Influence of Level of Vacuum in EBW quality. Fine-Vacuum High-Vacuum Non-vacuum 31 16

17 Fusion with Pressure Welding Resistance Welding Overview of Variants 32 Fusion Welding Processes Fusion but not only Resistance Welding Variants Spot Welding Projection Welding Seam Welding F I Flash Welding 33 17

18 Fusion Welding Processes Fusion but not only Resistance Welding Variants Spot Welding 34 Brasing and Soldering Interfacial Joining of Solid Base Materials by Third-body Fusion Filler Material 35 18

19 Classification of Welding Brazing and Soldering 36 Brazing and Soldering Fundaments and Application Samples Joining Mechanisms: Interfacial Diffusion (chemical) and/or Embedding (mechanical) Physical Principles: capillary (wetting and spreading) + fluidity + viscosity + vapor pressure + gravity + metallurgical interaction between Base Mat and Filler Mat 37 19

20 Solid State Welding and Processing Technology Solid State Welding Overview of Main Processes 38 Overview of Solid State Processes High-Frequency Welding (1/2) 39 20

21 Overview of Solid State Processes Flash Welding (1/1) 40 Overview of Solid State Processes Stud Welding (1/1) 41 21

22 Overview of Solid State Processes Cold Pressure Welding (1/2) 42 Overview of Solid State Processes Diffusion Welding (2/2) 43 22

23 Overview of Solid State Processes Ultrasonic Welding (1/4) Application to plastics 44 Overview of Solid State Processes Ultrasonic Welding (2/4) Interfaces in Ultrasonic Welding 45 23

24 Overview of Solid State Processes Explosion Welding (1/3) 46 Solid State Welding and Processing Technology Friction Based Technology Third-Body Region 47 24

25 Third-Body Region Based Technology 48 Friction Based Technology Sample of Processes Friction Welding Internacional Patent 2/1956 (A.I.Chudikov) 49 25

26 Overview of Solid State Processes Friction Welding (13/13) Application samples: Automotive industry 50 Friction Based Technology Sample of Processes Friction Linear Welding 51 26

27 Friction Stir Based Technology Friction Surfacing: Applications FS for Built-Up Production of Functionally Graded Materials (FGM) 52 Solid State Welding and Processing Technology Friction Stir Welding Fundaments 53 27

28 Overview of FSW Features Fundaments and Parameters A breakthrough innovation in welding technology patented in Dec 1991 Courtesy of RIFTEC - Germany 54 Friction Stir Welding Process Fundaments Example of Joints SPIF of tailored blanks welded by FSW 55 28

29 Aalto University ESAB LEGIO TM FSW 5UT Z-axis Control: Position + Speed + Force Maximum Forces: F z_max = 100kN (F x_max = F y_max = 40kN) Maximum Welding Travel Speed: V x_max = V y_max = 4m/min Maximum Spindle Power = 30kW ; Maximum Spindle Speed: max = 3000rpm Work Envelope (x ; y ; z) : 2000mm x 400mm x 300mm Special focus on the application to: Al, Cu, HSSteels, SSteels, and Ni based alloys 56 Industrial Application of FSW Aerospace Industry Boeing Co. New FSW for Space Launch System: Vertical Assembly Center (VAC) (NASA s Michoud Assembly Facility New Orleans) 61 m Tall x 8.4 m Diameter cryogenic liquid hydrogen and liquid oxygen that will feed the vehicle s RS-25 engine 57 29

30 Industrial Application of FSW Shipbuilding Industry Steel (source: HILDA project) FSW Aims to avoid This! Courtesy / Source: TWI 58 Industrial Application of FSW Apple imac

31 Other Advanced Welding Techniques A-Tig Welding Micro-Plasma Welding Hot-Wire Welding and Coating Narrow Gap Welding (w/ TIG hot wire; MIG; SAW) Advanced SAW: ICE Variant Advanced GMAW: Synergic Control + CMT + 3D Printing Hybrid Laser Welding with GMAW Friction Stir Based Innovations: FSChannelling + FSpot Welding Friction Welding (conventional axisymmetric) Friction Based Techniques: FHydro Pillar + FRiveting Friction Surfacing 60 Advanced TIG Technique A-TIG 61 31

32 Advanced PAW Technique Micro-Plasma (0.1 to 15 A) 62 Advanced GMAW Technique Robotized Welding + 3D Printing 63 32

33 Advanced Welding Technique Hybrid Laser Welding w/ GMAW 64 Epitaxial Solidification by Nucleation and grain growth Oriented (e.g. epitaxial) grain growth Segregation of elements into last zone solidifying (middle of fusion zone), that may promote nucleation effect Space between dendrites Cooling rate (e.g. welding parameters) Shape factor (penetration/width) Joining Mechanism in Fusion Welding 65 33

34 Shape and Sub-Zones in Fusion Welding keyhole Weld versus Conduction Weld E.g.: Plasma Welding; Electron Beam Welding; Laser Welding E.g.: SMAW; SAW; TIG; MIG Fusion Zone Heat Affected Zone 66 Formulation of Dilution Rate Autogeneous No filler material Homogeneous Filler metal similar to base material Heterogeneous Filler metal dissimilar to base material Dilution (Def.) Contribution of Base Material into weld metal (e.g. Base Materials + Filler Metal): TD=0% - Brasing and soldering TD=100% - Autogeneous 67 34

35 Joining Mechanisms Activated During Solid State Welding Aproximation to Interatomic Distances of Equilibrium Atomic bonding at joining materials interfaces Diffusion Bonding over an interferential layer which can reach up to continuous metallic conditions Clinching Mechanical interference 68 Nomenclature Standards Supporting Vocabulary (EN ISO 17659) EN ISO 17659:2002 Welding - Multilingual terms for welded joints with illustrations This International Standard describes by pictorial representation most of the more common terms, in English, French and German, for types of joints, joint preparation and welds. This International Standard can be used on its own or in conjunction with other similar standards. E.g.: AWS A3.0: Standard Welding Terms and Definitions - Including Terms for Adhesive Bonding, Brazing, Soldering, Thermal Cutting, and Thermal Spraying 69 35

36 Nomenclature Parts of a Fusion Weld 70 Nomenclature Parts of a Fusion Weld 71 36

37 Nomenclature Sizes in Welds 72 Nomenclature Sizes in Fillet Welds 73 37

38 Nomenclature Joints Types 74 Nomenclature Flanged Joints 75 38

39 Nomenclature Spliced Butt Joints 76 Nomenclature Joint Root 77 39

40 Nomenclature Groove Face; Root Edge; Root Face 78 Nomenclature Bevel: Depth, Angle, Face and Radius; Root Opening 79 40

41 Nomenclature Edge Shape 80 Nomenclature Single Groove Welds 81 41

42 Nomenclature Welds Joints with Backing alternative solutions 82 Nomenclature Double Groove Welds 83 42

43 Nomenclature Welds in Flanged Joints 84 Nomenclature Seam Welds and Spot Welds 85 43

44 Application Determines Welding Process Limits Application Nomenclature Other types of Welds 86 Weldability Concept Towards the Correct Welding Technological Solution Fulfillment of product properties and client demands Certain Level Certain Application (e.g. mechanical and corrosion properties) Solution: Welding Process Certain Precautions Quality level demanded by application Materials (composition + thermal treat.) Geometric features (thickness, global dimensions, accessibility, mobility, ) Place (indoor/outdoor) Series to produce (productivity) Welding specification procedures Welders approval + Security Assure Metallic Continuity 87 44

45 Weldability Concept Joint Design to Avoid Incomplete Penetration Incomplete Penetration does not Assure Metallic Continuity 88 Weldability Concept Complete Penetration 89 45

46 Weldability Concept Towards the Correct Welding Technological Solution Design of joints and their influence on the overall quality of the welded structure Type of joints Type of edge shape for each component Tolerances Design of joints criterion, depends on: Welding process Material Thickness of components Joint accessibility Assure Metallic Continuity e.g.: Stress Flow in complete penetration butt joint 90 References Literature supporting the achievement of the learning outcomes 1. J. F. Lancaster (1986) The Physics of Welding, 2 nd ed., Pergamon Press. 2. Robert W. Messler (2004) Principles of Welding Processes Physics, Chemistry, and Metallurgy, Jr. Wiley-VCH ed. Chapter 1: Introduction to the Process of Welding (pages 1 16) Chapter 5: Energy for Welding Closing Thoughts Other references ASM Metals Handbook Vol. 6 Welding Brazing and Soldering ASM International. AWS Welding Handbook Vol. 1 to 4 9th ed. American Welding Society