Butt welding

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Video: Automatic butt-welding machine

Butt welding is a commonly used technique in welding that can either be automated or done by hand on steel pieces. [1] Butt welding can also be done with brazing for copper pieces. It is used to attach two pieces of metal together such as pipe, framework in factories, and also flanges. [1] A flange is something that either is internal or external that provided to strengthen a piece of material. [1] In factories butt welding has shown how economical it can be for companies to use when building things out of metal. [1] This is because if they wanted to make something out of metal without welding it together they would have to bend everything and reinforce the structure which costs more than welding the two pieces together. [1] Butt welding is accomplished by heating up two pieces of metal, or applying pressure, or doing both of those. [1] Penetration while welding the metal is important to maintain and with thin pieces of metal this is possible however, with thick pieces edge preparation may have to be done to prepare the metal. [1] Full penetration butt welds are made when they are in the within the parent(bigger, stronger) metal. [1] In butt welding the strongest welds will have the fewest imperfections. To achieve this the heat input is controlled, which decreases the size of the weld. [1] In commercial welding when this is done it also reduces cost but in order to maintain the strength of the weld double butt welds will be used. [1] In butt welding there are two types used to achieve the specific welds and then there are also a variety of joints considered to be butt joints. [1]

Contents

Butt welding is best performed with MIG or TIG welding applications due to their natural ability to connect two pieces of metal together. [1] Using different types of welding electrodes for the welder will determine the properties of the weld such as its resistance against corrosion and strength. [1] Electrodes conduct current through the metal being welded in order join the two pieces. [1] The metal determines the type of welding that is required. [1] The electrodes are either heavily or lightly coated. For the heavily coated electrodes are commonly used in structural welding because they are much stronger and corrosion resistant. [1] The lightly coated electrodes are not as structurally sound. [1] Butt welding is performed with the Arc, TIG, or MIG welder held at a slight angle the weld if the weld is laying flat in order to achieve the least amount of porosity in the weld and also to increase the weld's strength. [1] Fillet welding make up about 80 percent of the connection despite being weaker that butt welds. [1] The reason it is used more often is because fillet welds offer more room for error with much larger tolerances. Fillet welding is not a type of butt weld despite its similarities. [1]

Types of butt welding

Flash

Flash butt welding is used with machinery and connects multiple pieces of metal together that are miss matched in size and shape. [2] These different sizings can oftentimes cause for breaks in welding process. [2] High voltage current is applied in order to connect the metal pieces together by applying it to both the components known as flashing in order to join them together. [2]

Resistance

This weld joins the two pieces of metal together by heat that comes from the pressure due to the metals being held together at a preset force. [2] Resistance butt welding is used on joints that are of similar shape and size and often the weld is performed in one movement unlike flash welding. [2]

Types of butt joints

Single-V Butt Weld Welded butt joint x-section.png
Single-V Butt Weld

There are many different types of butt welding joints and they all are named with their particular shape. [3] The joint also known as a square groove weld has many different forms in order to connect pieces of metal together and are all capable of bearing loads. [3] There are many different types of joints such as lap joints, tee joints, butt joints, and also corner joints. [3] Lap joints are two pieces that are end-over-end and welded together whereas butt welds are put end to end and connected that way. [3] Butt welds are connected to each other with the thickness of the parent metal. [3] There are many different kinds of butt welds such as square, single v, double v, single bevel, double bevel, single u, double u, single j, and also a double j. [3] Minimizing the distortions in a weld is important however doing so will minimize the chances of full penetration. [3] In order to get full penetration double welds such as double v, double j, and double u may be used. [3]

Standards

EN 1993-1-8, which covers the design of joints in the design of steel structures, defines a set of provisions for welding structural steel.

See also

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Flange external or internal ridge, or rim which provides strength

A flange is an external or internal ridge, or rim (lip), for strength, as the flange of an iron beam such as an I-beam or a T-beam; or for attachment to another object, as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera; or for a flange of a rail car or tram wheel. Thus flanged wheels are wheels with a flange on one side to keep the wheels from running off the rails. The term "flange" is also used for a kind of tool used to form flanges. Pipes with flanges can be assembled and disassembled easily.

Spot welding A process in which contacting metal surfaces are joined by heat from resistance to electric current

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.

Shielded metal arc welding manual arc welding process that uses a consumable electrode covered with a flux to lay the weld

Shielded metal arc welding (SMAW), also known as manual metal arc welding, flux shielded arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld.

Submerged arc welding

Submerged arc welding (SAW) is a common arc welding process. The first patent on the submerged-arc welding (SAW) process was taken out in 1935 and covered an electric arc beneath a bed of granulated flux. Originally developed and patented by Jones, Kennedy and Rothermund, the process requires a continuously fed consumable solid or tubular electrode. The molten weld and the arc zone are protected from atmospheric contamination by being "submerged" under a blanket of granular fusible flux consisting of lime, silica, manganese oxide, calcium fluoride, and other compounds. When molten, the flux becomes conductive, and provides a current path between the electrode and the work. This thick layer of flux completely covers the molten metal thus preventing spatter and sparks as well as suppressing the intense ultraviolet radiation and fumes that are a part of the shielded metal arc welding (SMAW) process.

Arc welding Process used to fuse metal by using heat from an electrical arc

Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals when cool result in a binding of the metals. It is a type of welding that uses a welding power supply to create an electric arc between a metal stick ("electrode") and the base material to melt the metals at the point of contact. Arc welders can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes.

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

Gas tungsten arc welding welding process that uses a non-consumable tungsten electrode

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Plasma arc welding (PAW) is an arc welding process similar to gas tungsten arc welding (GTAW). The electric arc is formed between an electrode and the workpiece. The key difference from GTAW is that in PAW, by positioning the electrode within the body of the torch, the plasma arc can be separated from the shielding gas envelope. The plasma is then forced through a fine-bore copper nozzle which constricts the arc and the plasma exits the orifice at high velocities and a temperature approaching 28,000 °C (50,000 °F) or higher.

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 resistance as an electrical 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.

Bevel edge of a structure that is not perpendicular to the faces of the piece

A bevelled edge (UK) or beveled edge (US) is an edge of a structure that is not perpendicular to the faces of the piece. The words bevel and chamfer overlap in usage; in general usage they are often interchanged, while in technical usage they may sometimes be differentiated as shown in the image at right. A bevel is typically used to soften the edge of a piece for the sake of safety, wear resistance, or aesthetics; or to facilitate mating with another piece.

English wheel

The English wheel, in Britain also known as a wheeling machine, is a metalworking tool that enables a craftsperson to form compound curves from flat sheets of metal such as aluminium or steel.

Piping and plumbing fitting piece that fits or connects pipes and tubes; used in pipe systems to connect straight pipe or tubing sections, adapt to different sizes or shapes and for other purposes

A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of water, gas, or liquid waste in domestic or commercial environments, within a system of pipes or tubes.

Orbital welding is a specialized area of welding whereby the arc is rotated mechanically through 360° around a static workpiece, an object such as a pipe, in a continuous process. The process was developed to addresses the issue of operator error in gas tungsten arc welding processes (GTAW). In orbital welding, computer-controlled process runs with little intervention from the operator. The process is used specifically for high quality repeatable welding.

A welding defect is any flaw that compromises the usefulness of a weldment. There is a great variety of welding defects. Welding imperfections are classified according to ISO 6520 while their acceptable limits are specified in ISO 5817 and ISO 10042.

Welding joint

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Gas metal arc welding welding process in which an electric arc forms between a consumable wire electrode and the workpieces, which heat up, melt and join; a gas feeds through the welding gun, shielding the process from contaminants in air

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Fillet weld

Fillet welding refers to the process of joining two pieces of metal together whether they be perpendicular or at an angle. These welds are commonly referred to as tee joints which are two pieces of metal perpendicular to each other or lap joints which are two pieces of metal that overlap and are welded at the edges. The weld is aesthetically triangular in shape and may have a concave, flat or convex surface depending on the welder’s technique. Welders use fillet welds when connecting flanges to pipes, welding cross sections of infrastructure, and when fastening metal by bolts isn't strong enough and wear off easily.

Extrusion welding is one of the processes used to weld thermoplastics and composites, developed in the 1960s as an evolution of hot gas welding. It can be a manual or automated process.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Kumar, Satish (2014). Designs of Steel Structure. NEM CHAND & BROS. ISBN   978-8185240732.
  2. 1 2 3 4 5 "What is Butt Welding?" (PDF). renown-oil-and-gas.co.uk.
  3. 1 2 3 4 5 6 7 8 B., Nielson (2017-05-09). "5 Types Of Welding Joints | Cliff's Welding Mesa, AZ". Cliff's Welding. Retrieved 2018-04-09.