Technology & Engineering
Metal Joining
Metal joining refers to the process of connecting metal parts to form a single, functional unit. This can be achieved through various methods such as welding, brazing, soldering, and mechanical fastening. The choice of joining method depends on factors like the type of metals being joined, the intended application, and the desired strength of the joint.
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10 Key excerpts on "Metal Joining"
eBook - PDF- Messler, Warren Savage(Authors)
- 2013(Publication Date)
- Butterworth-Heinemann(Publisher)
PART 2 Joining of Specific Material Types and Combinations This page intentionally left blank 11 Joining Advanced Metals, Alloys, and Inter metal lies 11.1 INTRODUCTION 11.1.1 Joining Process Options for Metals and Alloys Metals, more than most other materials, are used in structural applications, so joining of metals and their alloys is an extremely important process in fabrication and assem-bly. Much of the popularity of metals is related to their general high strength, ductility, toughness, and fabricability, including castability, formability, and machinability. Other desirable characteristics are electrical and thermal conductivity, resistance to many corrosive environments, and, for many, serviceability at elevated temperatures. The predominant method for joining metals and alloys is welding, which includes the subcategories of brazing and soldering, but essentially all other methods of joining, in-cluding mechanical fastening, adhesive bonding, thermal spraying, weldbonding, weldbrazing, and rivet-bonding are also possible and used. The reason for the popularity of welding, brazing, and soldering is that these processes result in strong joints through the creation of primary metallic bonds. Metals readily form metallic bonds with other metals, as long as intimate contact is achieved be-tween clean faying surfaces. For this reason, joining under the action of heat and/or pres-sure is relatively easy, and the resulting joints are sound. Resulting structural integrity is high, structural efficiency (i.e., strength-for-weight) and joint efficiency (i.e., joint to base material stress level ratios) are generally high, and physical properties such as electrical or thermal conductivity are essentially unaffected by the joint. Continuous welds also pro-vide excellent hermeticity and, done properly, provide superb environmental durability. Also popular as a joining method for metals and their alloys is mechanical fas-tening.
eBook - PDF- J. Beddoes, M. Bibby(Authors)
- 1999(Publication Date)
- Butterworth-Heinemann(Publisher)
Joining processes All of the previous chapters have focused on processes that primarily change the shape of individual components. Joining processes differ in that at least two compo- nents are joined together, thereby allowing more complicated or larger structures to be fabricated. A wide range of joining techniques are used in various manufacturing operations, including myriad different mechanical fasteners, adhesives, welding, braz- ing and soldering. Figure 8.1 classifies some of the major processes associated with each type of joining operation. Several joining operations are more akin to assembly than to metal processing. The major metal processing techniques include welding, brazing and soldering. A characteristic of these techniques is that the interatomic bonding within the base material, or at least on the surface, is altered, potentially changing the properties of the base material. The control of the base material proper- ties during joining requires special attention to process parameters and has important ramifications in terms of serviceability. In light of this situation, and in keeping with the metal processing emphasis of this book, this chapter deals with welding, brazing and soldering. As shown in Fig. 8.1, there are a number of welding processes available for joining. These techniques are applied to structures varying in size from pipelines of several thousand kilometres in length, supertankers and off-shore oil platforms, to intermedi- ate sized structures such as automobiles and railway rolling stock. In addition, many welding techniques are used to produce manufactured assemblies that may not appear to involve welding at all. Welding also has important applications for the repair of structural assemblies. Welding processes are conveniently divided into two classes: fusion welding and solid state welding.
- Yoseph Bar-Cohen(Author)
- 2018(Publication Date)
- CRC Press(Publisher)
12 Metal Joining Techniques Using BrazingYoseph Bar-Cohen , Dusan P. Sekulic , Rui Pan , Sudarsanam Suresh Babu , Anming Hu , Denzel Bridges , Xiaoqi Bao , Mircea Badescu , Hyeong Jae Lee , and Stewart Sherrit12.1 Introduction to Brazing12.1.1 Metal Joining Methods12.1.2 Process of Brazing12.1.3 General Applications of Brazing12.1.4 Design for Brazing12.2 Brazing: Science and Technology Issues12.2.1 System Definition and Phenomenology of the Brazing Process12.2.2 Process Conditions12.2.3 Joint Domain12.2.4 Wetting and Spreading of Molten Metal12.3 Modeling Brazing Materials for Properties and Performance12.3.1 Computational Models for Design for Braze Joint12.3.2 Computational Models for Braze Materials and Processes12.4 Typical heating methods12.4.1 Furnace Heating12.4.2 Induction Heating12.4.3 Resistive Heating12.4.4 Nanobrazing—Heating and Brazing at Lower Melting Temperature12.4.5 Laser Brazing12.5 Application of Brazing12.5.1 High-Temperature Alloys12.5.2 Planetary Application—Breaking the Chain of Contact to Mars and Other Planets12.5.2.1 Materials Properties12.5.2.2 Cylindrical Container Configuration Concept12.5.2.3 Spherical Container Configuration Concept12.5.2.4 Nanobrazing —Heating and Brazing at a Lower Melting Point12.6 Summary/ConclusionsAcknowledgments References12.1 Introduction to Brazing12.1.1 Metal Joining MethodsGenerally, there are three most dominant methods of materials (metal–metal, metal–nonmetal, or nonmetal–nonmetal) joining involving the use of melting as a form of integrating parts. These methods are soldering, brazing, and welding. The distinction among these methods is as follows and the focus of this chapter is on brazing, of either metals or nonmetals (e.g., ceramics). Joining methods that are based on adhesive bonding are described in Chapter 11 , while diffusion bonding is covered in Chapter 13
- Sherif D. El Wakil(Author)
- 2019(Publication Date)
- CRC Press(Publisher)
4 Joining of Metals When two parts of metal are to be attached together, the resulting joint can be made dismountable (using screws and the like), or it can be made permanent by employing riveting, welding, or brazing processes. The design of dismountable joints falls beyond the scope of this text and is covered in machine design. It is, therefore, the aim of this chapter to discuss the design and production of permanent joints when various technologies and methods are applied. Because the same equipment used in welding is also sometimes employed in the cutting of plates, thermal cutting processes will also be discussed in this chapter. 4.1 Riveting The process of riveting involves inserting a ductile metal pin through holes in two or more sheet metals and then forming over (heading) the ends of the metal pin so as to secure the sheet metals firmly together. This process can be performed either cold or hot, and each rivet is usually provided with one preformed head. Figure 4.1 a,b indicates the sequence of operations in riveting, while Figure 4.2 illustrates different shapes of preformed rivet heads. FIGURE 4.1 The sequence of operations in riveting: (a) flat-head rivet and (b) regular rivet. FIGURE 4.2 Different shapes of preformed rivet heads. 4.2 Welding Welding is the joining of two or more pieces of metal by creating atom-to-atom bonds between the adjacent surfaces through the application of heat, pressure, or both. In order for a welding technique to be industrially applicable, it must be reasonable in cost, yield reproducible or consistent weld quality, and, more important, produce joints with properties comparable to those of the base material. Various welding techniques have been developed that are aimed at achieving these three goals. However, no matter what welding method is used, the interface between the original two parts must disappear if a strong joint is to be obtained
eBook - ePub- T F Waters(Author)
- 2017(Publication Date)
- CRC Press(Publisher)
Most products are made by assembling a number of component parts, and many of these constituent items need to be joined together either permanently or in such a way that they can be subsequent taken apart again for maintenance or repair purposes. It is therefore essential that today’s design engineers are aware of the extensive range of joining methods readily available to modern industry and understand the fundamental principles involved in each process. The principal advantages and limitations of each technology should also be appreciated and joints designed accordingly.Tradition dies hard, and it is often all too easy to follow the joining methods used successfully in the past without giving due consideration to the more modern, economically attractive, options now available.5.1 The principal joining processes
The main joining processes used in manufacturing are welding, brazing, soldering, adhesive bonding and mechanical fastenings.hr/>Exercise Before reading further, list as many different joint applications as you can think of (from mending a broken cup to welding together the hull of a ship), stating which joining process you think each employed. Carefully save your list until you have worked through this chapter, as Question 5.1 is based upon its use.5.2 Welding processes
When one wishes to join together two or more parts permanently with a joint having strength at least equal to that of the material(s) from which the constituent parts are made, some form of welding is normally required. While a large number of welding methods are available, the majority of applications are well catered for by a relatively small group of processes.There are many general textbooks available (Niebel 1989, DeGarmo 1989, Gourd 1986) that include descriptions of the more specialized welding techniques, but the processes listed in Table 5.1
- Michael F. Ashby, Robert W. Messler, Rajiv Asthana, Edward P. Furlani, R. E. Smallman, A.H.W. Ngan, R. J Crawford, Nigel Mills(Authors)
- 2009(Publication Date)
- Butterworth-Heinemann(Publisher)
(Courtesy of Analog Devices, Inc., Cambridge, MA, with permission.) 508 C H A P T E R 1 2 . 1 Joining materials 12.1.6 Joining options 12.1.6.1 Fundamental forces involved in joining Joining is made possible by the following three d and only three d fundamental forces: (1) mechanical forces, (2) chemical forces, and (3) physical forces, which have their origin in electromagnetic forces. Not coincidentally, these three fundamental forces are, in turn, responsible for the three fundamental methods or processes by which materials and structures can be joined: (1) me-chanical joining, (2) adhesive bonding, and (3) welding. Mechanical forces arise from interlocking and resulting interference between parts, without any need for chemical or physical (electromagnetic) interaction. As shown in Figure 12.1-16 , such interlocking and in-terference can (and to some extent always does) arise at the microscopic level with surface asperities 6 giving rise to friction or, at macroscopic levels, using macroscopic features of the parts being joined. Chemical forces arise from chemical reactions between materials. Such re-actions can take place entirely in the solid state of the materials involved or can take place (often much more rapidly, uniformly, and completely) between a liquid and a solid phase of the materials involved, relying on wetting of the solid by the liquid. Finally, the naturally occurring attraction between atoms, oppositely charged ions, and molecules leads to bond formation and joining due to physical forces in what is generally referred to as welding. Brazing and soldering are special subclassifications of welding, that find their origin and effectiveness in the combined effects of chemical and mechanical forces (albeit with the strength of the ultimate joints, in both sub-classifications, arising from the physical forces of atomic bonding).
eBook - PDFJoining of Materials and Structures
From Pragmatic Process to Enabling Technology
- Robert W. Messler(Author)
- 2004(Publication Date)
- Butterworth-Heinemann(Publisher)
The future of information tech-nology will be enabled by microelectronics and nanoelectronics, optoelectronics, Figure 1.15 Joining has already become a more integrated part of the synthesis of materials, devices, and systems in microelectronics, where microjoining is used to hermet-ically seal critical electronic packages. (Courtesy of International Business Corporation, Poughkeepsie, NY, with permission.) 1.5 How Joining Is Changing or Must Change? 21 photonics, and molecular electronics (called ‘‘moletronics’’), and joining will enable these to act as a technology, not simply as a process. Likewise, much of the tremendous promise of biotechnology (e.g., gene splicing, tissue engineering, and the like) will also depend on joining as a technology more than as a pragmatic process. 1.6 JOINING OPTIONS 1.6.1 Fundamental Forces Involved in Joining Joining is made possible by the following three—and only three—fundamental forces: (1) mechanical forces, (2) chemical forces, and (3) physical forces, which have their origin in electromagnetic forces. Not coincidentally, these three fundamental forces are, in turn, responsible for the three fundamental methods or processes by which materials and structures can be joined: (1) mechanical joining, (2) adhesive bonding, and (3) welding. Mechanical forces arise from interlocking and resulting interference between parts, without any need for chemical or physical (electromagnetic) interaction. As shown in Figure 1.16, such interlocking and interference can (and to some extent always does) arise at the microscopic level with surface asperities 6 giving rise to friction or, at macroscopic levels, using macroscopic features of the parts being joined. Chem-ical forces arise from chemical reactions between materials.
eBook - PDF- Y N Zhou(Author)
- 2008(Publication Date)
- Woodhead Publishing(Publisher)
Part I Basics of microjoining This page intentionally left blank 3 1.1 Introduction Solid-state bonding processes are those which accomplish bonding without the requirement of resolidification of liquid metal. Typically, these processes take advantage of applied strain and/or heat for facilitate joining. Joining is largely the result of intimate intermetallic contact in the absence of local protective films. Solid-state bonding processes are the oldest of joining processes, with the official AWS definition of forge welding requiring an anvil and a hammer. 1 Solid-state bonding processes have proliferated particularly over the last several decades as new power systems have developed. General classifications of these processes include pressure processes (cold and hot pressure welding, etc.), resistance processes (butt, projection and seam welding, etc.), surface displacement processes (friction and ultrasonic welding, etc.), arc-heated processes (percussive welding, etc.), and diffusion bonding processes. Solid-state bonding has been developed and in some cases adopted for microjoining. For example, ultrasonic wire bonding (including thermosonic wire bonding), a variant of ultrasonic microwelding, is still the dominant technique for chip-level interconnection (Fig. 1.1). Cold pressure welding, and resistance seam and projection welding have been used to seal electronic packages (Fig. 1.2). In this chapter, mechanisms of bonding are described for those processes using both mechanically applied straining and heating. Detailed examinations of bonding mechanisms of the other processes are available in the references. These include the cold-pressure welding processes, 2–8 and the diffusion bonding processes. 9–12 (also see Chapter 9) and wire bonding (Chapter 8). These processes can be thought of as having two generally separable stages. These include a heating stage, and an upsetting stage.
eBook - PDF- Mikell P. Groover(Author)
- 2012(Publication Date)
- Wiley(Publisher)
The joint consists of braze (filler) metal; no base metal is fused in the joint. (Credit: Fundamentals of Modern Manufacturing, 4 th Edition by Mikell P. Groover, 2010. Reprinted with permission of John Wiley & Sons, Inc.) Section 24.1/Brazing 559 into the joint as in a conventional fusion-welding process. The principal application of braze welding is repair work. 24.2 SOLDERING Soldering is similar to brazing and can be defined as a joining process in which a filler metal with melting point (liquidus) not exceeding 450 C (840 F) is melted and distrib- uted by capillary action between the faying surfaces of the metal parts being joined. As in brazing, no melting of the base metals occurs, but the filler metal wets and combines with the base metal to form a metallurgical bond. Details of soldering are similar to those of brazing, and many of the heating methods are the same. Surfaces to be soldered must be precleaned so they are free of oxides, oils, and so on. An appropriate flux must be applied to the faying surfaces, and the surfaces are heated. Filler metal, called solder, is added to the joint, which distributes itself between the closely fitting parts. In some applications, the solder is precoated onto one or both of the surfaces—a process called tinning, irrespective of whether the solder contains any tin. Typical clearances in soldering range from 0.075 mm to 0.125 mm (0.003 in to 0.005 in), except when the surfaces are tinned, in which case a clearance of about 0.025 mm (0.001 in) is used. After solidification, the flux residue must be removed. As an industrial process, soldering is most closely associated with electronics assembly. It is also used for mechanical joints, but not for joints subjected to elevated stresses or temperatures.
- Rob Thompson(Author)
- 2021(Publication Date)
- Thames and Hudson Ltd(Publisher)
Ceramics can be joined together and to metals. Many ceramics can be joined, but brazing is generally reserved for engineering materials due to the sophistication of the process. A similar process to brazing, known as diffusion bonding, is suitable for joining ceramic, glass and composite materials. This process joins materials in a vacuum chamber, using a small amount of Featured Manufacturer Alessi www.alessi.com pressure and very thin film of filler coated onto the joint interface. When the temperature is raised a very small amount of pressure is applied, which causes the molecules in the joint to mix and form a strong bond. Dissimilar materials, such as metals and ceramics, can be joined in this way. COSTS There are no tooling costs. But jigs may be necessary to support the assembly. However, joints can be designed to locate and therefore do not need to be jigged. Cycle time is rapid and ranges from 1–10 minutes for most torch applications. The cycle time for furnace techniques may be longer, but is offset because multiple products can be joined simultaneously. Labour costs are generally low. ENVIRONMENTAL IMPACTS Soldering and brazing operate at lower temperatures than are welding. There are very few rejects because faulty parts can be dismantled and reassembled. 3 4 5 6 316 THERMAL Thermoplastic studs are heated and formed into permanent joints. This process is suitable for joining dissimilar materials such as plastic to metal. There are 2 main techniques: hot air and ultrasonic staking.
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