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Resistance Welding
Electric resistance welding (ERW) is a welding process where metal parts in contact are permanently joined by heating them with an electric current, melting the metal at the joint. Electric resistance welding is widely used, for example, in manufacture of steel pipe and in assembly of bodies for automobiles. The electric current can be supplied to electrodes that also apply clamping pressure, or may be induced by an external magnetic field. The electric resistance welding process can be further classified by the geometry of the weld and the method of applying pressure to the joint: spot welding, seam welding, flash welding, projection welding, for example. Some factors influencing heat or welding temperatures are the proportions of the workpieces, the metal coating or the lack of coating, the electrode materials, electrode geometry, electrode pressing force, electrical current and length of welding time. Small pools of molten metal are formed at the point of most electrical resista ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welding
Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as brazing and soldering, which do not melt the base metal (parent metal). In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that, based on weld configuration (butt, full penetration, fillet, etc.), can be stronger than the base material. Pressure may also be used in conjunction with heat or by itself to produce a weld. Welding also requires a form of shield to protect the filler metals or melted metals from being contaminated or oxidized. Many different energy sources can be used for welding, including a gas flame (chemical), an electric arc (electrical), a laser, an electron beam, friction, and ultrasound. While often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shot Welding
{{refimprove, date=November 2022 Shot welding is a type of spot welding used to join two pieces of metal together. This is accomplished by clamping the two pieces together and then passing a large electric current through them for a short period of time. Shot welding was invented by Earl J. Ragsdale, a mechanical engineer at the Budd Company, in 1932 to weld stainless steel. This welding method was used to construct the '' Pioneer Zephyr''. Method The E. G. Budd Company of Philadelphia recognized the important metallurgical characteristics of 18/8 stainless steel (known today as SAE 304 austenitic stainless steel) and developed a spot welding process to take advantage of the oxidized layer on the surface of stainless steel. Heat treating the 18-8 stainless steel leaves the metal with non-magnetic and ductile properties. Repeatedly reheating the metal to 1000–1100°C impairs the mechanical and chemical properties of the metal. The metal becomes susceptible to corrosion due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Welding Processes
This is a list of welding processes, separated into their respective categories. The associated ''N reference numbers'' (second column) are specified in ISO 4063 (in the European Union published as ''EN ISO 4063''). Numbers in parentheses are obsolete and were removed from the current (1998) version of ISO 4063. The AWS reference codes of the American Welding Society are commonly used in North America."Welding Inspection Handbook", 3rd edition, American Welding Society, , Miami, FL, pp. 10-11 (2000) Arc welding Oxyfuel gas welding Resistance welding Solid-state welding Other types of welding Notes and references *Cary, Howard B. and Scott C. Helzer (2005). Modern Welding Technology. Upper Saddle River, New Jersey: Pearson Education. . *Lincoln Electric (1994). The Procedure Handbook of Arc Welding. Cleveland: Lincoln Electric. . See also * Welding * List of welding codes This page lists published welding codes, procedures, and specifications. American Society of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stud Welding
Stud welding is a technique similar to flash welding where a fastener or specially formed nut is welded onto another metal part, typically a base metal or substrate. The fastener can take different forms, but typically fall under threaded, unthreaded, or tapped. The bolts may be automatically fed into the stud welder. Weld nuts generally have a flange with small nubs that melt to form the weld. ''Weld studs'' are used in stud welding systems. Manufacturers create weld studs for the two main forms of stud welding: capacitor discharge stud welding and drawn arc stud welding Drawn arc stud welding Drawn arc stud welding joins a stud and another piece of metal together by heating both parts with an arc. The stud is usually joined to a flat plate by using the stud as one of the electrodes. The polarity used in stud welding depends on the type of metal being used. Welding aluminium, for example, would usually require direct-current electrode positive (DCEP). Welding steel would re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Arc
An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The current through a normally nonconductive medium such as air produces a plasma; the plasma may produce visible light. An arc discharge is characterized by a lower voltage than a glow discharge and relies on thermionic emission of electrons from the electrodes supporting the arc. An archaic term is voltaic arc, as used in the phrase "voltaic arc lamp". Techniques for arc suppression can be used to reduce the duration or likelihood of arc formation. In the late 19th century, electric arc lighting was in wide use for public lighting. Some low-pressure electric arcs are used in many applications. For example, fluorescent tubes, mercury, sodium, and metal-halide lamps are used for lighting; xenon arc lamps have been used for movie projectors. Electric arcs can be utilized for manufacturing processes, such as electric arc welding, and electric arc fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resistance And Conductance
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (), while electrical conductance is measured in siemens (S) (formerly called the 'mho' and then represented by ). The resistance of an object depends in large part on the material it is made of. Objects made of electrical insulators like rubber tend to have very high resistance and low conductance, while objects made of electrical conductors like metals tend to have very low resistance and high conductance. This relationship is quantified by resistivity or conductivity. The nature of a material is not the only factor in resistance and conductance, however; it also depends on the size and shape of an object because these properties are extensive rather than int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Current
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of an electric charge, which can be either positive or negative, produces an electric field. The movement of electric charges is an electric current and produces a magnetic field. When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by Coulomb's law. If the charge moves, the electric field would be doing work on the electric charge. Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Material Properties
A materials property is an intensive property of a material, i.e., a physical property that does not depend on the amount of the material. These quantitative properties may be used as a metric by which the benefits of one material versus another can be compared, thereby aiding in materials selection. A property may be a constant or may be a function of one or more independent variables, such as temperature. Materials properties often vary to some degree according to the direction in the material in which they are measured, a condition referred to as anisotropy. Materials properties that relate to different physical phenomena often behave linearly (or approximately so) in a given operating range. Modeling them as linear functions can significantly simplify the differential constitutive equations that are used to describe the property. Equations describing relevant materials properties are often used to predict the attributes of a system. The properties are measured by standard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filler Metals
A filler metal is a metal added in the making of a joint through welding, brazing, or soldering. Soldering Soldering and brazing processes rely on a filler metal added to the joint to form the junction between the base metal parts. Soft soldering uses a filler that melts at a lower temperature than the workpiece, often a lead-tin solder alloy. Brazing and hard soldering use a higher temperature filler that melts at a temperature which may approach that of the base metal, and which may form a eutectic alloy with the base metal. Filler alloys have a lower melting point than the base metal, so that the joint may be made by bringing the whole assembly up to temperature without everything melting as one. Complex joints, typically for jewelry or live steam boilermaking, may be made in stages, with filler metals of progressively lower melting points used in turn. Early joints are thus not destroyed by heating to the later temperatures. Welding Welding processes work around the meltin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upset Welding
Upset welding (UW)/resistance butt welding is a welding technique that produces coalescence simultaneously over the entire area of abutting surfaces or progressively along a joint, by the heat obtained from resistance to electric current An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The movi ... through the area where those surfaces are in contact. Pressure is applied before heating is started and is maintained throughout the heating period. The equipment used for upset welding is very similar to that used for flash welding. It can be used only if the parts to be welded are equal in cross-sectional area. The abutting surfaces must be very carefully prepared to provide for proper heating. The difference from flash welding is that the parts are clamped in the welding machine and force is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projection Welding
A spot welder Spot welding (or resistance spot welding) is a type of electric resistance welding used to weld various sheet metal products, through a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current. The process uses two shaped copper alloy electrodes to concentrate welding current into a small "spot" and to simultaneously clamp the sheets together. Work-pieces are held together under pressure exerted by electrodes. Typically the sheets are in the thickness range. Forcing a large current through the spot will melt the metal and form the weld. The attractive feature of spot welding is that a large amount of energy can be delivered to the spot in a very short time (approximately 10–100 milliseconds). This permits the welding to occur without excessive heating of the remainder of the sheet. The amount of heat (energy) delivered to the spot is determined by the resistance between the electrodes and the magnitude a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pipeline Transport
Pipeline transport is the long-distance transportation of a liquid or gas through a system of Pipe (fluid conveyance), pipes—a pipeline—typically to a market area for consumption. The latest data from 2014 gives a total of slightly less than of pipeline in 120 countries of the world. The United States had 65%, Russia had 8%, and Canada had 3%, thus 76% of all pipeline were in these three countries. ''Pipeline and Gas Journals worldwide survey figures indicate that of pipelines are planned and under construction. Of these, represent projects in the planning and design phase; reflect pipelines in various stages of construction. Liquids and gases are transported in pipelines, and any chemically stable substance can be sent through a pipeline. Pipelines exist for the transport of crude and refined petroleum, fuels – such as oil, natural gas and biofuels – and other fluids including sewage, slurry, water, beer, hot water or steam for shorter distances. Pipelines are useful f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
