Misplaced Pages

#162837

99-475: Welding is a fabrication process that joins materials, usually metals or thermoplastics , primarily by using high temperature to melt the parts together and allow them to cool, causing fusion . Common alternative methods include solvent welding (of thermoplastics) using chemicals to melt materials being bonded without heat, and solid-state welding processes which bond without melting, such as pressure, cold welding , and diffusion bonding . Metal welding

198-401: A square wave pattern instead of the normal sine wave , making rapid zero crossings possible and minimizing the effects of the problem. Resistance welding involves the generation of heat by passing current through the resistance caused by the contact between two or more metal surfaces. Small pools of molten metal are formed at the weld area as high current (1,000–100,000 A ) is passed through

297-600: A vowel shift , so that in the 16th century the language resembled modern Swedish more than before. The printing of the New Testament in Swedish in 1526 marked the starting point for modern Swedish. In this period Old Swedish had taken in a large amount of new vocabulary primarily from Latin, Low German and Dutch. When the country became part of the Kalmar Union in 1397, many Danish scribes brought Danicisms into

396-502: A Russian, Konstantin Khrenov eventually implemented the first underwater electric arc welding. Gas tungsten arc welding , after decades of development, was finally perfected in 1941, and gas metal arc welding followed in 1948, allowing for fast welding of non- ferrous materials but requiring expensive shielding gases. Shielded metal arc welding was developed during the 1950s, using a flux-coated consumable electrode, and it quickly became

495-703: A common form and a genitive (some dialects retain distinct dative forms). There were also three grammatical genders (masculine, feminine and neuter), still retained in many dialects today, but now reduced to two in the standard language, where the masculine and feminine have merged. These features of Old Swedish are still found in modern Icelandic and Faroese ; the noun declensions are almost identical. Noun declensions fell under two categories: weak and strong. The weak masculine, feminine and neuter nouns had their own declensions and at least three groups of strong masculine nouns, three groups of strong feminine nouns and one group of strong neuter nouns can be identified. Below

594-479: A few dialects well into the 20th century. Other major changes include the loss of a separate inflectional system for masculine and feminine nouns, pronouns and adjectives in the course of the 15th century, leaving only two genders in the standard Swedish language, although three genders are still common in many of the dialects. The old dative forms of the personal pronouns became the object forms ( honom , henne , dem ; him, her, them) and -s became more common as

693-412: A highly concentrated, limited amount of heat, resulting in a small HAZ. Arc welding falls between these two extremes, with the individual processes varying somewhat in heat input. To calculate the heat input for arc welding procedures, the following formula can be used: where Q = heat input ( kJ /mm), V = voltage ( V ), I = current (A), and S = welding speed (mm/min). The efficiency is dependent on

792-409: A highly focused laser beam, while electron beam welding is done in a vacuum and uses an electron beam. Both have a very high energy density, making deep weld penetration possible and minimizing the size of the weld area. Both processes are extremely fast, and are easily automated, making them highly productive. The primary disadvantages are their very high equipment costs (though these are decreasing) and

891-519: A low-temperature oven to relieve residual stresses . Such weldments, particularly those for engine blocks, may be line-bored after heat treatment. After the weldment has cooled, seams are usually ground clean, and the assembly can be sandblasted , primed and painted. Any additional manufacturing is then performed, and the finished product is inspected and shipped. Many fabrication shops offer specialty processes, including : Old Swedish Old Swedish ( Modern Swedish : fornsvenska )

990-511: A modest amount of training and can achieve mastery with experience. Weld times are rather slow, since the consumable electrodes must be frequently replaced and because slag, the residue from the flux, must be chipped away after welding. Furthermore, the process is generally limited to welding ferrous materials, though special electrodes have made possible the welding of cast iron , stainless steel, aluminum, and other metals. Gas metal arc welding (GMAW), also known as metal inert gas or MIG welding,

1089-718: A multitude of value-added processes, including welding, cutting, forming and machining. As with other manufacturing processes, both human labor and automation are commonly used. A fabricated product may be called a fabrication , and shops specializing in this type of work are called fab shops . The end products of other common types of metalworking, such as machining , metal stamping , forging , and casting , may be similar in shape and function, but those processes are not classified as fabrication. Fabrication comprises or overlaps with various metalworking specialties: Standard metal fabrication materials are: A variety of tools are used to cut raw material. The most common cutting method

SECTION 10

#1732791307163

1188-476: A repeatable form that can be used to create products for many industries, including jewelry, aerospace, automotive, construction, civil and architectural. Machining is a specialized trade of removing material from a block of metal to make it a desired shape. Fab shops generally have some machining capability, using metal lathes , mills , drills , and other portable machining tools. Most solid components, such as gears, bolts, screws and nuts, are machined. Welding

1287-445: A suitable torch was developed. At first, oxyfuel welding was one of the more popular welding methods due to its portability and relatively low cost. As the 20th century progressed, however, it fell out of favor for industrial applications. It was largely replaced with arc welding, as advances in metal coverings (known as flux ) were made. Flux covering the electrode primarily shields the base material from impurities, but also stabilizes

1386-433: A susceptibility to thermal cracking. Developments in this area include laser-hybrid welding , which uses principles from both laser beam welding and arc welding for even better weld properties, laser cladding , and x-ray welding . Like forge welding (the earliest welding process discovered), some modern welding methods do not involve the melting of the materials being joined. One of the most popular, ultrasonic welding ,

1485-524: A tungsten electrode but uses plasma gas to make the arc. The arc is more concentrated than the GTAW arc, making transverse control more critical and thus generally restricting the technique to a mechanized process. Because of its stable current, the method can be used on a wider range of material thicknesses than can the GTAW process and it is much faster. It can be applied to all of the same materials as GTAW except magnesium, and automated welding of stainless steel

1584-480: Is shearing . Special band saws for cutting metal have hardened blades and feed mechanisms for even cutting. Abrasive cut-off saws, also known as chop saws, are similar to miter saws but have a steel-cutting abrasive disks. Cutting torches can cut large sections of steel with little effort. Burn tables are CNC (computer-operated) cutting torches, usually powered by natural gas. Plasma and laser cutting tables, and water jet cutters , are also common. Plate steel

1683-419: Is a hazardous undertaking and precautions are required to avoid burns , electric shock , vision damage, inhalation of poisonous gases and fumes, and exposure to intense ultraviolet radiation . Until the end of the 19th century, the only welding process was forge welding , which blacksmiths had used for millennia to join iron and steel by heating and hammering. Arc welding and oxy-fuel welding were among

1782-427: Is a highly productive, single-pass welding process for thicker materials between 1 inch (25 mm) and 12 inches (300 mm) in a vertical or close to vertical position. To supply the electrical power necessary for arc welding processes, a variety of different power supplies can be used. The most common welding power supplies are constant current power supplies and constant voltage power supplies. In arc welding,

1881-472: Is a ring surrounding the weld in which the temperature of the welding process, combined with the stresses of uneven heating and cooling, alters the heat-treatment properties of the alloy. The effects of welding on the material surrounding the weld can be detrimental—depending on the materials used and the heat input of the welding process used, the HAZ can be of varying size and strength. The thermal diffusivity of

1980-429: Is a semi-automatic or automatic process that uses a continuous wire feed as an electrode and an inert or semi-inert gas mixture to protect the weld from contamination. Since the electrode is continuous, welding speeds are greater for GMAW than for SMAW. A related process, flux-cored arc welding (FCAW), uses similar equipment but uses wire consisting of a steel electrode surrounding a powder fill material. This cored wire

2079-432: Is allowed to cool, and then another weld is performed on top of it. This allows for the welding of thick sections arranged in a single-V preparation joint, for example. After welding, a number of distinct regions can be identified in the weld area. The weld itself is called the fusion zone—more specifically, it is where the filler metal was laid during the welding process. The properties of the fusion zone depend primarily on

SECTION 20

#1732791307163

2178-490: Is an overview of the noun declension system: The noun declension system Some noun paradigms of the words fisker (fish), sun (son), siang (bed), skip (ship), biti (bit) and vika (week): By the year 1500 the number of cases in Old Swedish had been reduced from four ( nominative , genitive , dative and accusative ) to two (nominative and genitive). The dative case, however, lived on in

2277-440: Is characterized by a stable arc and high-quality welds, but it requires significant operator skill and can only be accomplished at relatively low speeds. GTAW can be used on nearly all weldable metals, though it is most often applied to stainless steel and light metals. It is often used when quality welds are extremely important, such as in bicycle , aircraft and naval applications. A related process, plasma arc welding, also uses

2376-406: Is commonly used for making electrical connections out of aluminum or copper, and it is also a very common polymer welding process. Another common process, explosion welding , involves the joining of materials by pushing them together under extremely high pressure. The energy from the impact plasticizes the materials, forming a weld, even though only a limited amount of heat is generated. The process

2475-623: Is commonly used for welding dissimilar materials, including bonding aluminum to carbon steel in ship hulls and stainless steel or titanium to carbon steel in petrochemical pressure vessels. Other solid-state welding processes include friction welding (including friction stir welding and friction stir spot welding ), magnetic pulse welding , co-extrusion welding, cold welding , diffusion bonding , exothermic welding , high frequency welding , hot pressure welding, induction welding , and roll bonding . Welds can be geometrically prepared in many different ways. The five basic types of weld joints are

2574-434: Is covered with a flux that protects the weld area from oxidation and contamination by producing carbon dioxide (CO 2 ) gas during the welding process. The electrode core itself acts as filler material, making a separate filler unnecessary. The process is versatile and can be performed with relatively inexpensive equipment, making it well suited to shop jobs and field work. An operator can become reasonably proficient with

2673-413: Is distinct from lower temperature bonding techniques such as brazing and soldering , which do not melt the base metal (parent metal) and instead require flowing a filler metal to solidify their bonds. In addition to melting the base metal in welding, 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 can be stronger than

2772-415: Is in the way the past tense ( preterite ) is formed: strong verbs form it with a vowel shift in the root of the verb, while weak verbs form it with a dental suffix (þ, d or t). The verbs in the table below are bīta (bite), biūþa (offer), wærþa (become), stiæla (steal), mæta (measure) and fara (go). Weak verbs are grouped into four classes: Inside the conjugation classes

2871-525: Is loaded on the table and the parts are cut out as programmed. The support table consists of a grid of bars that can be replaced when worn. Higher-end burn tables may include CNC punch capability using a carousel of punches and taps. In fabrication of structural steel by plasma and laser cutting , robots move the cutting head in three dimensions around the cut material. Forming converts flat sheet metal into 3-D parts by applying force without adding or removing material. The force must be great enough to change

2970-431: Is more expensive than the standard solid wire and can generate fumes and/or slag, but it permits even higher welding speed and greater metal penetration. Gas tungsten arc welding (GTAW), or tungsten inert gas (TIG) welding, is a manual welding process that uses a non-consumable tungsten electrode, an inert or semi-inert gas mixture, and a separate filler material. Especially useful for welding thin materials, this method

3069-420: Is obtained by a metallic or chemical bond that is formed between the constituent atoms. Chemical bonds can be grouped into two types consisting of ionic and covalent . To form an ionic bond, either a valence or bonding electron separates from one atom and becomes attached to another atom to form oppositely charged ions . The bonding in the static position is when the ions occupy an equilibrium position where

Welding - Misplaced Pages Continue

3168-429: Is one important application of the process. A variation of the process is plasma cutting , an efficient steel cutting process. Submerged arc welding (SAW) is a high-productivity welding method in which the arc is struck beneath a covering layer of flux. This increases arc quality since contaminants in the atmosphere are blocked by the flux. The slag that forms on the weld generally comes off by itself, and combined with

3267-665: Is related to the Old Swedish word valla , meaning 'to boil', which could refer to joining metals, as in valla järn (literally "to boil iron"). Sweden was a large exporter of iron during the Middle Ages , so the word may have entered English from the Swedish iron trade, or may have been imported with the thousands of Viking settlements that arrived in England before and during the Viking Age , as more than half of

3366-407: Is shared by the molecule as a whole. In both ionic and covalent bonding the location of the ions and electrons are constrained relative to each other, thereby resulting in the bond being characteristically brittle . Fabrication (metal) Typically, a fabrication shop bids on a job, usually based on engineering drawings , and if awarded the contract, builds the product. Large fab shops employ

3465-445: Is sometimes protected by some type of inert or semi- inert gas , known as a shielding gas, and filler material is sometimes used as well. One of the most common types of arc welding is shielded metal arc welding (SMAW); it is also known as manual metal arc welding (MMAW) or stick welding. Electric current is used to strike an arc between the base material and consumable electrode rod, which is made of filler material (typical steel) and

3564-436: Is still widely used for welding pipes and tubes, as well as repair work. The equipment is relatively inexpensive and simple, generally employing the combustion of acetylene in oxygen to produce a welding flame temperature of about 3100 °C (5600 °F). The flame, since it is less concentrated than an electric arc, causes slower weld cooling, which can lead to greater residual stresses and weld distortion, though it eases

3663-510: Is the main focus of steel fabrication. Formed and machined parts are assembled and tack-welded in place, then rechecked for accuracy. If multiple weldments have been ordered, a fixture may be used to locate parts for welding. A welder then finishes the work according to engineering drawings (for detailed welding) or by their own experience and judgement (if no details are provided). Special measures may be needed to prevent or correct warping of weldments due to heat. These may include redesigning

3762-435: Is the name for two distinct stages of the Swedish language that were spoken in the Middle Ages : Early Old Swedish ( Klassisk fornsvenska ), spoken from about 1225 until about 1375, and Late Old Swedish ( Yngre fornsvenska ), spoken from about 1375 until about 1526. Old Swedish developed from Old East Norse , the eastern dialect of Old Norse . The earliest forms of the Swedish and Danish languages , spoken between

3861-408: Is the word vindöga (window). Many words related to seafaring were borrowed from Dutch. It is speculated that the influence of Low German was so strong that it helped break down the inflectional system of Old Swedish. In contrast to the stable Early Old Swedish, Late Old Swedish ( yngre fornsvenska ; 1375–1526) experienced many changes, including a simplification of the grammatical system and

3960-469: Is used to connect thin sheets or wires made of metal or thermoplastic by vibrating them at high frequency and under high pressure. The equipment and methods involved are similar to that of resistance welding, but instead of electric current, vibration provides energy input. When welding metals, the vibrations are introduced horizontally, and the materials are not melted; with plastics, which should have similar melting temperatures, vertically. Ultrasonic welding

4059-452: The Westro- and North Bothnian tongues in northern Sweden. The most defining difference between Old Swedish and modern Swedish was the more complex grammatical system of the former. In Old Swedish nouns, adjectives, pronouns and certain numerals were inflected in four cases ( nominative , genitive , dative and accusative ), whereas modern standard Swedish has reduced the case system to

Welding - Misplaced Pages Continue

4158-651: The phonemes /i/ and /j/ (e.g. siæl (soul), själ in modern Swedish). The graphemes ⟨u⟩ , ⟨v⟩ , and ⟨w⟩ were used interchangeably with the phonemes /w/ ~ /v/ and /u/ (e.g. vtan (without), utan in modern Swedish), and ⟨w⟩ could also sometimes stand for the consonant-vowel combinations /vu/ and /uv/ : dwa ( duva or dove). Certain abbreviations were used in writing, such as mꝫ for meþ (modern med , with). The letter combinations ⟨aa⟩ , ⟨ae⟩ and ⟨oe⟩ were often written so that one of

4257-459: The 1590 version this was changed to " ...thei shullen welle togidere her swerdes in-to scharris... " (they shall weld together their swords into plowshares), suggesting this particular use of the word probably became popular in English sometime between these periods. The Old English word for welding iron was samod ('to bring together') or samodwellung ('to bring together hot'). The word

4356-420: The 1930s and then during World War II. In 1930, the first all-welded merchant vessel, M/S Carolinian , was launched. During the middle of the century, many new welding methods were invented. In 1930, Kyle Taylor was responsible for the release of stud welding , which soon became popular in shipbuilding and construction. Submerged arc welding was invented the same year and continues to be popular today. In 1932

4455-563: The Soviet scientist N. F. Kazakov proposed the diffusion bonding method. Other recent developments in welding include the 1958 breakthrough of electron beam welding, making deep and narrow welding possible through the concentrated heat source. Following the invention of the laser in 1960, laser beam welding debuted several decades later, and has proved to be especially useful in high-speed, automated welding. Magnetic pulse welding (MPW) has been industrially used since 1967. Friction stir welding

4554-465: The arc and can add alloying components to the weld metal. World War I caused a major surge in the use of welding, with the various military powers attempting to determine which of the several new welding processes would be best. The British primarily used arc welding, even constructing a ship, the "Fullagar" with an entirely welded hull. Arc welding was first applied to aircraft during the war as well, as some German airplane fuselages were constructed using

4653-436: The atmosphere. Porosity and brittleness were the primary problems, and the solutions that developed included the use of hydrogen , argon , and helium as welding atmospheres. During the following decade, further advances allowed for the welding of reactive metals like aluminum and magnesium . This in conjunction with developments in automatic welding, alternating current, and fluxes fed a major expansion of arc welding during

4752-433: The base material plays a large role—if the diffusivity is high, the material cooling rate is high and the HAZ is relatively small. Conversely, a low diffusivity leads to slower cooling and a larger HAZ. The amount of heat injected by the welding process plays an important role as well, as processes like oxyacetylene welding have an unconcentrated heat input and increase the size of the HAZ. Processes like laser beam welding give

4851-486: The base material. 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 an industrial process, welding may be performed in many different environments, including in open air, under water , and in outer space . Welding

4950-535: The beginning of modern Swedish words came from the Low German be- , ge- and vor- . Some words were replaced with new ones: the native word for window, vindøgha , was replaced with fönster , eldhus (kitchen) was replaced with kök and gælda (to pay) with betala . Some of these words still exist in Modern Swedish but are often considered archaic or dialectal; one example

5049-402: The butt joint, lap joint, corner joint, edge joint, and T-joint (a variant of this last is the cruciform joint ). Other variations exist as well—for example, double-V preparation joints are characterized by the two pieces of material each tapering to a single center point at one-half their height. Single-U and double-U preparation joints are also fairly common—instead of having straight edges like

SECTION 50

#1732791307163

5148-517: The distance between the wire and the base material is quickly rectified by a large change in current. For example, if the wire and the base material get too close, the current will rapidly increase, which in turn causes the heat to increase and the tip of the wire to melt, returning it to its original separation distance. The type of current used plays an important role in arc welding. Consumable electrode processes such as shielded metal arc welding and gas metal arc welding generally use direct current, but

5247-442: The durability of many designs increases significantly. Most solids used are engineering materials consisting of crystalline solids in which the atoms or ions are arranged in a repetitive geometric pattern which is known as a lattice structure . The only exception is material that is made from glass which is a combination of a supercooled liquid and polymers which are aggregates of large organic molecules. Crystalline solids cohesion

5346-599: The electrode can be charged either positively or negatively. In welding, the positively charged anode will have a greater heat concentration, and as a result, changing the polarity of the electrode affects weld properties. If the electrode is positively charged, the base metal will be hotter, increasing weld penetration and welding speed. Alternatively, a negatively charged electrode results in more shallow welds. Non-consumable electrode processes, such as gas tungsten arc welding, can use either type of direct current, as well as alternating current. However, with direct current, because

5445-441: The electrode only creates the arc and does not provide filler material, a positively charged electrode causes shallow welds, while a negatively charged electrode makes deeper welds. Alternating current rapidly moves between these two, resulting in medium-penetration welds. One disadvantage of AC, the fact that the arc must be re-ignited after every zero crossings, has been addressed with the invention of special power units that produce

5544-404: The electrode perfectly steady, and as a result, the arc length and thus voltage tend to fluctuate. Constant voltage power supplies hold the voltage constant and vary the current, and as a result, are most often used for automated welding processes such as gas metal arc welding, flux-cored arc welding, and submerged arc welding. In these processes, arc length is kept constant, since any fluctuation in

5643-399: The ending for the genitive singular. Adjectives and certain numerals were inflected according to the gender and case the noun they modified was in. Below is a table of the inflection of weak adjectives. Verbs in Old Swedish were conjugated according to person and number. There were four weak verb conjugations and six groups of strong verbs . The difference between weak and strong verbs

5742-437: The filler metal used, and its compatibility with the base materials. It is surrounded by the heat-affected zone , the area that had its microstructure and properties altered by the weld. These properties depend on the base material's behavior when subjected to heat. The metal in this area is often weaker than both the base material and the fusion zone, and is also where residual stresses are found. Many distinct factors influence

5841-613: The first processes to develop late in the century, and electric resistance welding followed soon after. Welding technology advanced quickly during the early 20th century, as world wars drove the demand for reliable and inexpensive joining methods. Following the wars, several modern welding techniques were developed, including manual methods like shielded metal arc welding , now one of the most popular welding methods, as well as semi-automatic and automatic processes such as gas metal arc welding , submerged arc welding , flux-cored arc welding and electroslag welding . Developments continued with

5940-485: The following way: ēn ( twēr , þrīr , etc.) ok tiughu , ēn ok þrǣtighi , etc. This is an extract from the Westrogothic law ( Västgötalagen ), which is the oldest continuous text written in the Swedish language, and was compiled during the early 13th century. The text marks the beginning of Old Swedish. Modern Swedish : English : This text about Eric IX (ca. 1120–1160) can be found in

6039-581: The invention of laser beam welding , electron beam welding , magnetic pulse welding , and friction stir welding in the latter half of the century. Today, as the science continues to advance, robot welding is commonplace in industrial settings, and researchers continue to develop new welding methods and gain greater understanding of weld quality. The term weld is derived from the Middle English verb well ( wæll ; plural/present tense: wælle ) or welling ( wællen ), meaning 'to heat' (to

SECTION 60

#1732791307163

6138-535: The invention of metal electrodes in the late 1800s by a Russian, Nikolai Slavyanov (1888), and an American, C. L. Coffin (1890). Around 1900, A. P. Strohmenger released a coated metal electrode in Britain , which gave a more stable arc. In 1905, Russian scientist Vladimir Mitkevich proposed using a three-phase electric arc for welding. Alternating current welding was invented by C. J. Holslag in 1919, but did not become popular for another decade. Resistance welding

6237-412: The length of the arc is directly related to the voltage, and the amount of heat input is related to the current. Constant current power supplies are most often used for manual welding processes such as gas tungsten arc welding and shielded metal arc welding, because they maintain a relatively constant current even as the voltage varies. This is important because in manual welding, it can be difficult to hold

6336-503: The letters stood above the other as a smaller letter, ⟨aͣ⟩ , ⟨aͤ⟩ and ⟨oͤ⟩ , which led to the development of the modern letters ⟨å⟩ , ⟨ä⟩ , and ⟨ö⟩ . The root syllable length in Old Swedish could be short ( VC ), long ( VːC , VCː ) or overlong ( VːCː ). During the Late Old Swedish period the short root syllables ( VC ) were lengthened and

6435-531: The material may not have the ability to withstand the stress and could cause cracking, one method the control these stress would be to control the heating and cooling rate, such as pre-heating and post- heating The durability and life of dynamically loaded, welded steel structures is determined in many cases by the welds, in particular the weld transitions. Through selective treatment of the transitions by grinding (abrasive cutting) , shot peening , High-frequency impact treatment , Ultrasonic impact treatment , etc.

6534-715: The maximum temperature possible); 'to bring to a boil'. The modern word was probably derived from the past-tense participle welled ( wællende ), with the addition of d for this purpose being common in the Germanic languages of the Angles and Saxons . It was first recorded in English in 1590. A fourteenth century translation of the Christian Bible into English by John Wycliffe translates Isaiah 2:4 as " ...thei shul bete togidere their swerdes into shares... " (they shall beat together their swords into plowshares). In

6633-531: The metal's initial shape. Forming can be controlled with tools such as punches and dies. Machinery can regulate force magnitude and direction. Machine-based forming can combine forming and welding to produce lengths of fabricated sheeting (e.g. linear grating for water drainage). Most metallic materials, being at least somewhat ductile and capable of considerable permanent deformation without cracking or breaking, lend themselves particularly well to these techniques. Proper design and use of tools with machinery creates

6732-423: The metal. In general, resistance welding methods are efficient and cause little pollution, but their applications are somewhat limited and the equipment cost can be high. Spot welding is a popular resistance welding method used to join overlapping metal sheets of up to 3 mm thick. Two electrodes are simultaneously used to clamp the metal sheets together and to pass current through the sheets. The advantages of

6831-696: The method include efficient energy use , limited workpiece deformation, high production rates, easy automation, and no required filler materials. Weld strength is significantly lower than with other welding methods, making the process suitable for only certain applications. It is used extensively in the automotive industry—ordinary cars can have several thousand spot welds made by industrial robots . A specialized process called shot welding , can be used to spot weld stainless steel. Like spot welding, seam welding relies on two electrodes to apply pressure and current to join metal sheets. However, instead of pointed electrodes, wheel-shaped electrodes roll along and often feed

6930-647: The most common English words in everyday use are Scandinavian in origin. The history of joining metals goes back several millennia. The earliest examples of this come from the Bronze and Iron Ages in Europe and the Middle East . The ancient Greek historian Herodotus states in The Histories of the 5th century BC that Glaucus of Chios "was the man who single-handedly invented iron welding". Forge welding

7029-414: The most popular metal arc welding process. In 1957, the flux-cored arc welding process debuted, in which the self-shielded wire electrode could be used with automatic equipment, resulting in greatly increased welding speeds, and that same year, plasma arc welding was invented by Robert Gage. Electroslag welding was introduced in 1958, and it was followed by its cousin, electrogas welding , in 1961. In 1953,

7128-512: The overlong root syllables ( VːCː ) were shortened, so modern Swedish only has the combinations VːC and VCː . Unlike in modern Swedish, a short vowel in Old Swedish did not entail a long consonant. There were eight vowels in Early Old Swedish: /iː, yː, uː, oː, eː, aː, øː, ɛː/ . A vowel shift ( stora vokaldansen ) occurred during the Late Old Swedish period, which had the following effects: The consonant sounds were largely

7227-524: The piece to require less welding, employing staggered welding, using a stout fixture, covering the weldment in sand as it cools, and post-weld straightening. Straightening of warped steel weldments is done with an oxyacetylene torch . In this highly specialized work, heat is selectively applied to the steel in a slow, linear sweep, causing the steel to contract in the direction of the sweep as it cools. A highly skilled welder can remove significant warpage this way. Steel weldments are occasionally annealed in

7326-429: The process, and the industry continued to grow during the following centuries. In 1800, Sir Humphry Davy discovered the short-pulse electrical arc and presented his results in 1801. In 1802, Russian scientist Vasily Petrov created the continuous electric arc, and subsequently published "News of Galvanic-Voltaic Experiments" in 1803, in which he described experiments carried out in 1802. Of great importance in this work

7425-551: The process. Also noteworthy is the first welded road bridge in the world, the Maurzyce Bridge in Poland (1928). During the 1920s, significant advances were made in welding technology, including the introduction of automatic welding in 1920, in which electrode wire was fed continuously. Shielding gas became a subject receiving much attention, as scientists attempted to protect welds from the effects of oxygen and nitrogen in

7524-441: The quality of welding procedure specification , how to judge the skill of the person performing the weld, and how to ensure the quality of a welding job. Methods such as visual inspection , radiography , ultrasonic testing , phased-array ultrasonics , dye penetrant inspection , magnetic particle inspection , or industrial computed tomography can help with detection and analysis of certain defects. The heat-affected zone (HAZ)

7623-650: The quality of a weld, either destructive or nondestructive testing methods are commonly used to verify that welds are free of defects, have acceptable levels of residual stresses and distortion, and have acceptable heat-affected zone (HAZ) properties. Types of welding defects include cracks, distortion, gas inclusions (porosity), non-metallic inclusions, lack of fusion, incomplete penetration, lamellar tearing, and undercutting. The metalworking industry has instituted codes and specifications to guide welders , weld inspectors , engineers , managers, and property owners in proper welding technique, design of welds, how to judge

7722-427: The resulting force between them is zero. When the ions are exerted in tension force, the inter-ionic spacing increases creating an electrostatic attractive force, while a repulsing force under compressive force between the atomic nuclei is dominant. Covalent bonding takes place when one of the constituent atoms loses one or more electrons, with the other atom gaining the electrons, resulting in an electron cloud that

7821-561: The same as in modern Swedish, with the notable exceptions of / ð / and / θ / , which do not exist in modern Swedish (although the former is preserved in Elfdalian and to some extent also the latter). The Modern Swedish tje-sound ([ɕ]) and sje-sound ([ɧ]) were probably [t͡ʃ] and [ʃ] , respectively, similar to their values in modern Finland Swedish . A similar change can be seen from Old Spanish [t͡s/d͡z] and [ʃ/ʒ] to Modern Spanish [s/θ] and [x] . The Proto-Germanic phoneme / w /

7920-666: The single-V and double-V preparation joints, they are curved, forming the shape of a U. Lap joints are also commonly more than two pieces thick—depending on the process used and the thickness of the material, many pieces can be welded together in a lap joint geometry. Many welding processes require the use of a particular joint design; for example, resistance spot welding, laser beam welding, and electron beam welding are most frequently performed on lap joints. Other welding methods, like shielded metal arc welding, are extremely versatile and can weld virtually any type of joint. Some processes can also be used to make multipass welds, in which one weld

8019-603: The strength of welds and the material around them, including the welding method, the amount and concentration of energy input, the weldability of the base material, filler material, and flux material, the design of the joint, and the interactions between all these factors. For example, the factor of welding position influences weld quality, that welding codes & specifications may require testing—both welding procedures and welders—using specified welding positions: 1G (flat), 2G (horizontal), 3G (vertical), 4G (overhead), 5G (horizontal fixed pipe), or 6G (inclined fixed pipe). To test

8118-482: The use of mor din (mother yours) has been common. Below is a table of the Old Swedish personal pronouns : The Old Swedish cardinal numbers are as follows. Numbers from one to four decline in the nominative, genitive, dative and accusative cases and in all three genders (masculine, feminine and neuter); here the nominative forms are given. Numbers above four are indeclinable. The higher numbers are as follows. The numbers 21–29, 31–39, and so on are formed in

8217-466: The use of a continuous wire feed, the weld deposition rate is high. Working conditions are much improved over other arc welding processes, since the flux hides the arc and almost no smoke is produced. The process is commonly used in industry, especially for large products and in the manufacture of welded pressure vessels. Other arc welding processes include atomic hydrogen welding , electroslag welding (ESW), electrogas welding , and stud arc welding . ESW

8316-446: The weak verbs are also categorised into further three classes: Word order was less restricted in Old Swedish than modern Swedish due to complex verbal morphology. Both referential and nonreferential subjects could be left out as verbal structures already conveyed the necessary information, in much the same way as in languages such as Spanish and Latin . In nominal phrases the genitive attribute could stand both before and after

8415-414: The welding of high alloy steels. A similar process, generally called oxyfuel cutting, is used to cut metals. These processes use a welding power supply to create and maintain an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct current (DC) or alternating current (AC), and consumable or non-consumable electrodes . The welding region

8514-418: The welding process used, with shielded metal arc welding having a value of 0.75, gas metal arc welding and submerged arc welding, 0.9, and gas tungsten arc welding, 0.8. Methods of alleviating the stresses and brittleness created in the HAZ include stress relieving and tempering . One major defect concerning the HAZ would be cracking at the toes , due to the rapid expansion (heating) and contraction (cooling)

8613-661: The word it modified, i.e. one could say his house or house his . The same was true for pronouns and adjectives ( that house or house that ; green pasture or pasture green ). During the Late Old Swedish period the usage of the genitive attribute became increasingly more restricted, and it nearly always came to be placed before the word it modified, so in modern Swedish one would usually only say hans hus (his house), or in some dialects or manners of emphasis, huset hans , but almost never hus hans . However, this too has lived on in some dialects, like in Västgötska , where

8712-582: The workpiece, making it possible to make long continuous welds. In the past, this process was used in the manufacture of beverage cans, but now its uses are more limited. Other resistance welding methods include butt welding , flash welding , projection welding , and upset welding . Energy beam welding methods, namely laser beam welding and electron beam welding , are relatively new processes that have become quite popular in high production applications. The two processes are quite similar, differing most notably in their source of power. Laser beam welding employs

8811-504: The written language. The Middle Low German language also influenced Old Swedish due to the economic and political power of the Hanseatic League during the 13th and 14th centuries. Accordingly, loanwords relating to warfare, trade, crafts and bureaucracy entered the Swedish language directly from Low German, along with some grammatical suffixes and conjunctions. The prefixes be- , ge- and för- that can be found in

8910-515: The written language. Old Swedish used some letters that are no longer found in modern Swedish: ⟨ æ ⟩ and ⟨ ø ⟩ were used for modern ⟨ ä ⟩ and ⟨ ö ⟩ respectively, and ⟨ þ ⟩ could stand for both / ð / ( th as in that) and / θ / ( th as in thing). In the latter part of the 14th century ⟨þ⟩ was replaced with ⟨th⟩ and ⟨dh⟩ . The grapheme ⟨i⟩ could stand for both

9009-442: The years 800 and 1100, were dialects of Old East Norse and are referred to as Runic Swedish and Runic Danish because at the time all texts were written in the runic alphabet . The differences were only minute, however, and the dialects truly began to diverge around the 12th century, becoming Old Swedish and Old Danish in the 13th century. It is not known when exactly Elfdalian began to diverge from Swedish. Early Old Swedish

9108-415: Was also developed during the final decades of the 19th century, with the first patents going to Elihu Thomson in 1885, who produced further advances over the next 15 years. Thermite welding was invented in 1893, and around that time another process, oxyfuel welding , became well established. Acetylene was discovered in 1836 by Edmund Davy , but its use was not practical in welding until about 1900, when

9207-516: Was invented in 1991 by Wayne Thomas at The Welding Institute (TWI, UK) and found high-quality applications all over the world. All of these four new processes continue to be quite expensive due to the high cost of the necessary equipment, and this has limited their applications. The most common gas welding process is oxyfuel welding, also known as oxyacetylene welding. It is one of the oldest and most versatile welding processes, but in recent years it has become less popular in industrial applications. It

9306-500: Was markedly different from modern Swedish in that it had a more complex case structure and had not yet experienced a reduction of the gender system and thus had three genders. Nouns, adjectives, pronouns and certain numerals were inflected in four cases: nominative , genitive , dative and accusative . The writing of the Westrogothic law marked the beginning of Early Old Swedish ( klassisk fornsvenska or äldre fornsvenska ; 1225–1375), which had developed from Old East Norse. It

9405-508: Was preserved in initial sounds in Old Swedish (w-) and did survive in rural Swedish dialects in the provinces of Skåne , Halland , Västergötland and south of Bohuslän into the 18th, 19th and 20th centuries. It is still preserved in the Dalecarlian dialects in the province of Dalarna , Sweden. The / w / -phoneme did also occur after consonants (kw-, tw- etc.) in Old Swedish and did so into modern times in said dialects, as well as in

9504-453: Was the description of a stable arc discharge and the indication of its possible use for many applications, one being melting metals. In 1808, Davy, who was unaware of Petrov's work, rediscovered the continuous electric arc. In 1881–82 inventors Nikolai Benardos (Russian) and Stanisław Olszewski (Polish) created the first electric arc welding method known as carbon arc welding using carbon electrodes. The advances in arc welding continued with

9603-537: Was the first Swedish language document written in the Latin alphabet , and its oldest fragments have been dated to around the year 1225. Old Swedish was relatively stable during this period. The phonological and grammatical systems inherited from Old Norse were relatively well preserved and did not experience any major changes. Most of the texts from the Early Old Swedish period were written in Latin , as it

9702-588: Was the language of knowledge and the Church . However, Old Swedish was used as a literary language as well, and laws especially were written in it; of the 28 surviving manuscripts from this period, 24 contain law texts. Much of the knowledge of Old Swedish comes from these law texts. In addition to laws, some religious and poetic texts were also written in Old Swedish. The Catholic Church and its various monastic orders introduced many new Greek and Latin loanwords into Old Swedish. Latin especially had an influence on

9801-530: Was used in the construction of the Iron pillar of Delhi , erected in Delhi , India about 310 AD and weighing 5.4  metric tons . The Middle Ages brought advances in forge welding , in which blacksmiths pounded heated metal repeatedly until bonding occurred. In 1540, Vannoccio Biringuccio published De la pirotechnia , which includes descriptions of the forging operation. Renaissance craftsmen were skilled in

#162837