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.
Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the reduction of cations of that metal by means of a direct electric current. The part to be coated acts as the cathode of an electrolytic cell; the electrolyte is a solution of a salt of the metal to be coated; and the anode is usually either a block of that metal, or of some inert conductive material. The current is provided by an external power supply.
Ball bonding is a type of wire bonding, and is the most common way to make the electrical interconnections between a bare silicon die and the lead frame of the package it is placed in during semiconductor device fabrication.
Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale: from huge ships, buildings, and bridges down to precise engine parts and delicate jewelry.
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
Plasma cutting is a process that cuts through electrically conductive materials by means of an accelerated jet of hot plasma. Typical materials cut with a plasma torch include steel, stainless steel, aluminum, brass and copper, although other conductive metals may be cut as well. Plasma cutting is often used in fabrication shops, automotive repair and restoration, industrial construction, and salvage and scrapping operations. Due to the high speed and precision cuts combined with low cost, plasma cutting sees widespread use from large-scale industrial computer numerical control (CNC) applications down to small hobbyist shops.
Friction welding (FWR) is a solid-state welding and bonding process that generates heat through mechanical friction between workpieces in relative motion to one another. This process, with the addition of a lateral force called "upset" to plastically displace and fuse the materials. No melting occurs, friction welding is not a fusion welding process, but a solid-state welding technique more like forge welding. Friction welding is used with metals and thermoplastics in a wide variety of aviation and automotive applications.
Friction stir welding (FSW) is a solid-state joining process that uses a non-consumable tool to join two facing workpieces without melting the workpiece material. Heat is generated by friction between the rotating tool and the workpiece material, which leads to a softened region near the FSW tool. While the tool is traversed along the joint line, it mechanically intermixes the two pieces of metal, and forges the hot and softened metal by the mechanical pressure, which is applied by the tool, much like joining clay, or dough. It is primarily used on wrought or extruded aluminium and particularly for structures which need very high weld strength. FSW is capable of joining aluminium alloys, copper alloys, titanium alloys, mild steel, stainless steel and magnesium alloys. More recently, it was successfully used in welding of polymers. In addition, joining of dissimilar metals, such as aluminium to magnesium alloys, has been recently achieved by FSW. Application of FSW can be found in modern shipbuilding, trains, and aerospace applications.
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, electric current and length of welding time. Small pools of molten metal are formed at the point of most electrical resistance as an electric current is passed through the metal. In general, resistance welding methods are efficient and cause little pollution, but their applications are limited to relatively thin materials.
Turning is a machining process in which a cutting tool, typically a non-rotary tool bit, describes a helix toolpath by moving more or less linearly while the workpiece rotates.
Electron-beam physical vapor deposition, or EBPVD, is a form of physical vapor deposition in which a target anode is bombarded with an electron beam given off by a charged tungsten filament under high vacuum. The electron beam causes atoms from the target to transform into the gaseous phase. These atoms then precipitate into solid form, coating everything in the vacuum chamber with a thin layer of the anode material.
Thermal spraying techniques are coating processes in which melted materials are sprayed onto a surface. The "feedstock" is heated by electrical or chemical means.
Hyperbaric welding is the process of welding at elevated pressures, normally underwater. Hyperbaric welding can either take place wet in the water itself or dry inside a specially constructed positive pressure enclosure and hence a dry environment. It is predominantly referred to as "hyperbaric welding" when used in a dry environment, and "underwater welding" when in a wet environment. The applications of hyperbaric welding are diverse—it is often used to repair ships, offshore oil platforms, and pipelines. Steel is the most common material welded.
Fusion welding is a generic term for welding processes that rely on melting to join materials of similar compositions and melting points. Due to the high-temperature phase transitions inherent to these processes, a heat-affected zone is created in the material.
Pin brazing is an easy, metallurgically safe method of making electrical connections to steel and ductile iron pipelines as well as other metallic structures, which are to be cathodically protected or electrically earthed.
A submarine pipeline is a pipeline that is laid on the seabed or below it inside a trench. In some cases, the pipeline is mostly on-land but in places it crosses water expanses, such as small seas, straits and rivers. Submarine pipelines are used primarily to carry oil or gas, but transportation of water is also important. A distinction is sometimes made between a flowline and a pipeline. The former is an intrafield pipeline, in the sense that it is used to connect subsea wellheads, manifolds and the platform within a particular development field. The latter, sometimes referred to as an export pipeline, is used to bring the resource to shore. Sizeable pipeline construction projects need to take into account many factors, such as the offshore ecology, geohazards and environmental loading – they are often undertaken by multidisciplinary, international teams.
Friction stir spot welding is a pressure welding process that operates below the melting point of the workpieces. It is a variant of friction stir welding.
Aluminium alloys are often used due to their high strength-to-weight ratio, corrosion resistance, low cost, high thermal and electrical conductivity. There are a variety of techniques to join aluminium including mechanical fasteners, welding, adhesive bonding, brazing, soldering and friction stir welding (FSW), etc. Various techniques are used based on the cost and strength required for the joint. In addition, process combinations can be performed to provide means for difficult-to-join assemblies and to reduce certain process limitations.
Underwater work is work done underwater, generally by divers during diving operations, but includes work done underwater by remotely operated vehicles and crewed submersibles.
Marine construction is the process of building structures in or adjacent to large bodies of water, usually the sea. These structures can be built for a variety of purposes, including transportation, energy production, and recreation. Marine construction can involve the use of a variety of building materials, predominantly steel and concrete. Some examples of marine structures include ships, offshore platforms, moorings, pipelines, cables, wharves, bridges, tunnels, breakwaters and docks. Marine construction may require diving work, but professional diving is expensive and dangerous, and may involve relatively high risk, and the types of tools and equipment that can both function underwater and be safely used by divers are limited. Remotely operated underwater vehicles (ROVs) and other types of submersible equipment are a lower risk alternative, but they are also expensive and limited in applications, so when reasonably practicable, most underwater construction involves either removing the water from the building site by dewatering behind a cofferdam or inside a caisson, or prefabrication of structural units off-site with mainly assembly and installation done on-site.
