Science History and Development of Las a. Definition of welding according to the American Welding Society, 1989
Welding is the process of joining metallic or non logamyang done by heating the material to be connected to the welding temperature who carried out: with or without the use of pressure (pressure), only the pressure (pressure), or with or without filler metal (filler)
b. The definition of the classification by the British Standards Institution, 1983
Classification is the process of joining two or more materials in a plastic or liquid by heat (heat) or pressure (pressure) or both. Metal filler (filler metals) with the same melting temperature and melting point of the parent metal or without the use of the connection process.
II. The history of welding
historians estimate that the ancient Egyptians started menggunakanpengelasan pressure in 5500 BC (for membuatpipa denganmemalu copper sheets that cover the edges together). Winterton quotes that bendaseni Egyptians made in 3000 BC consisted of the base material of copper and gold smelting and beating results. This type of classification, called the welding wrought {Forge welding), is the first human effort in connecting two pieces of metal. Examples of welding forging a famous ancient Damascus swords made by casting iron layers of different nature. Classification
forging have been developed and important to the ancient Romans that they called a god as a Vulcan (god of fire and metal working) for the state of art. Now the word is used for the treatment of vulcanizing rubber with sulfur, but the first word means "hardened". These days welding forging practically been abandoned and the last made by a blacksmith. years 1901-1903 Fouche and Picard develop welding rod that can digunakandengan acetylene (carbide gas), so since it began the era of welding
danpemotongan oksiasetilen (carbide gas oxygen). The period between 1903 and 1918 was a period of use of welding terutamasebagai way improvements, and The most rapid growth occurred during World War I (1914-1918). proven welding technique can be applied primarily to repair the damaged ship. Winterton reported that in 1917 there were 103 ships in the American enemy is damaged and the number of workers in welding operations increased from 8000 to 33,000 during the period 1914-1918. After 1919, the use of welding as construction and manufacturing techniques began to develop the first mwnggunakan electrode alloys (alloy) of copper-tungsten for welding point in 1920. In the period 1930-1950 there were many improvements in the development of welding machines. The process of arc flash setting (submerged) are covered under the arc nyalanya flux powder first used commercially in 1934 and patented in 1935. Now there are more than 50 kinds of welding processes that can be used to connect a variety of metals and alloys. Classification
we see today is far more complex and already well developed. Advances in welding technology, not so fast until 1877. Before 1877, the process of forging and welding peyolderan been used for 3000 years. The origin of electric resistance welding resistance welding {) began around 1877 when Prof. Elihu Thompson began experiments on the reversal of the polarity of the transformer coils, he received his first patent in 1885 and the electrical resistance welding machine {blunt resistance butt welding) was first demonstrated at the American Institute Fair in 1887. In 1889, Coffin granted a patent for welding dull flame of particles (flash-butt welding) which is a blunt welding process is important. Zerner in 1885 to introduce arc welding process nayala carbon {carbon arc welding) using two carbon electrodes, and NG Slavinoff in 1888 in Russia was the first to use flame metal arc process using bare electrode (without coating). Coffin who work independently are also investigating flame metal arc process and get the U.S. patent in 1892. In 1889, the AP Strohmeyer introduced the concept of metal-coated electrode to eliminate many problems that arise in the use of bare electrodes.
Thomas Fletcher in 1887 using inflatable pipe that burns hydrogen and oxygen, and showed that he can cut or melt metal. On the use and development of welding technology
III. The use and development of welding technology, welding technology usage
At this present time welding technique has been used widely utilized in various fields. The wide use of welding technology due to buildings and machinery are made using this welding technique becomes cheaper
scope of the use of welding techniques in the construction of a very broad include shipbuilding, bridges, steel frame, pressure vessels, pipes rapidly, pipelines, rail vehicles and so on.
addition to the manufacture of welding, welding processes can also be used to repair for example, to fill holes in castings, make a hard coating on tools, strengthen the parts that are worn and various other repairs. Welding is not the main purpose of the construction but only a means to achieve better production economies. Therefore, the design and how welding should really pay attention to compatibility between the properties of welded construction purposes and circumstances surrounding Las Technology Development
I. Electric Arc Welding
For centuries las temopa used as the primary process for connecting the metal without much headway. In the early 19th century, found a new way of electric arc welding flame (Elekctric Arc Welding) with carbon electrode bars without the wrapper by using the battery as a power source. The main disadvantages of electric welding process is the oxidation of carbon is relatively high in the weld (weld easily rust) so that the welding is widely used.
At the same time, in 1877, found welding resistance (Resistance Welding). A physicist from England, James Joule, is recognized as the inventor. In 1856 he memenaskan two wire rod with a flow of electricity. During the heating process, the wire is pressed to one another. It turns out the two wires are attached to each other after heated.
In further developments, resistane welding produces several types of welding processes, eg, welding flash (Flas Welding) 1920.las in electrical resistance achieved prominence after created various types of robots. To meet the needs of developed various forms of electric resistance welding including spot welding, interval, seam (line) and projection. Las prosenya implement this in the heat and press. Electrode serves as the dealer and the current emphasis plate-shaped workpiece.
On next decade, introduced last hermit (Thermit Welding) based on chemical procedure that adds kesanah welding technology. Las thermiddiperoleh by pouring molten metal between two metal ends that will be connected so it would melt. After the second freeze fused metal and liquid metal is poured to function as an additive agent.
In the late 19th century found oxy acetylene welding, weld it managed to shift the use of welding wrought and dominate the welding process for several decades to develop electric welding .. In 1925
oxy acetylene welding is shifted by the improvement in electric arc welding in which the arc welding using covered electrode. After the fire, wrapping the electrode to produce gas and slag. Gas protection crater of the weld from oxidation during the welding process is underway. Slag protects the weld during the freezing process to cool (until the slag is cleaned). Limitations of arc welding electrode length ektode bullion is limited so that each period must be stopped replace welding electrode. Tanbah material efficiency is far from 100% because there must be puntngnya.
Based on the weaknesses in the late 1930s it created arc welding electrode coils. In principle, welding is not necessary to stop before reaching the end of the welding line. And welding can be done by semi-automatic or automatic. As a patron used flux. Flux is poured shortly upfront electrode so that electric flame arc buried by the flux. Advantages, operator is not dazzled by the electric arc flame, weakness, limited welding position just below the hands at other positions scattered flux will fall before the function.
In 1941 in the United States found Tungsten electrode. Tungsten does not melt by the heat of electric arc flame so it does not terumpan in the weld. As a protective gas used core (Inert) that for a few moments to survive on the conditions. Core gas sprayed so that the weld weld kedaerah avoid oxidation. Because the use of welding as a protective material welding core is often called TIG welding (Tungsten Inert Gas). The success of core gas usage
pad pad pad pad tungsten electrode also attempted roll in the early 1950s. This process is hereinafter referred to as Gas Metal Arc Welding (GMAW) or MIG welding (Metal Inert Gas). Kaena metered gas is very expensive then used a mixture of argon and oxygen gas or CO gas is quite active. Welding is usually called with Metal Active Gas (MAG). Can also be used protective argon mixture with CO for not more than 20% the result is quite good because it does not leave the slag. Please note that the protective gas is more expensive gas, then the way is only used for special purposes. Next
found arc welding electrode with a protective weld rolls floured. In order to be used in any position, the electrode is made hollow like a pipe to put the flux. This process is relatively much cheaper than gas arc welding, it can be for all position welding can be developed and technical a semi-automatic or fully automatic welding is called flux core arc welding electrodes (Flux Core Arc Welding) Next there is the electrode as a component to be installed in other parts. Las called
stud welding. Stud mounted on the main body through three phases, namely the setting position, the search ends and objects stud stud emphasis on primary and main object just after arc ignition is turned off.
After that developed Inggi frequency electric welding is 10,000 to 500,000 Hz. High frequency electrical welding is often called induction welding. Judging from the process of unification of the work piece, solid welding includes welding aided by heat to break down the layer of oxidation or dirt on the surface of the workpiece. Heat a very thin surface of the object dihasilakan work that is very suitable for welding thin plate.
In the 1950s, transforms electrical energy into a beam of electrons is fired at the workpiece. The heat generated is larger and the dimensions used electron is much smaller than electric arc flame, pengelasannya very quickly it is very suitable for mass production. Hot regions become more narrow so it is suitable for materials that are sensitive to heat changes. Excellent weld quality and accuracy, it's just very expensive equipment. This method is called weld electron (Electron Beam Welding).
II. Las Scratch
In 1950, AL Chudikov, an engineer from the Soviet Union, expressed its observations about the theory of mechanical energy can be converted into heat energy. Friction that occurs in engine parts that move caused many losses as some mechanical energy converted into heat generated. Chudikov argues, so the bias should be used in the welding process. After going through experiment and research he managed to weld by utilizing the heat caused by friction. To increase the heat that occurs, the work piece is not only played but pressed against one another. The pressure also serves to accelerate fusion. This is called friction welding (Welding Friktion)
III.Las Plasma arc plasma flame
Las electricity (Plasma Arc Welding). Plasma process is actually an improvement las tungsren, it's just a flame electric arc appearing between electrodes with workpiece but appears between the tip electrode with a core gas flow in the vicinity. Las plasma turned out better than tungsten because arc welding electric flame that appears more stable with a smaller diameter so that the heat is more concentrated. Bias welding process faster, besides tungsten never touches the workpiece.
IV.Las
Early Vote in 1960 was marked by the discovery of welding that uses high frequency sound (ultrasonic welding). It also uses electric welding in the working process, there is no power on the workpiece, the heat generated solely the result of the process and it is only helpful in the process of unification of the workpiece.
voice that ranged from 10,000 to 175,000 Hz, the sound vibrations channeled through sosotrode mounted on the workpiece. Then pressure is applied to the workpiece during the process. The advantages of this process is suitable for thin objects and not affected the types of materials attached. Not wearing thermal energy as the main energy is its own advantages in certain materials and thin, only less successful for workpiece thickness above 2.5 mm x 2. Various forms of ultrasonic welding
:
Wedge reed spot.
Leteral drive spot.
Overthung copuler spot.
Line.
Ring.
Continuous seam.
V. Las eksplosive (Exsplosive Welding or EXW)
Las eksplosive (Exsplosive Welding or EXW) was developed from observations of someone the days of World War I, there are fragments of a bomb strongly attached to the other metals fell. Carl in his research menyimpulakan that the bomb fragments stuck because of the effects of jet in the event of collision. Stock jet capable of cleaning dirt on the surface of two objects so that it contacts between atoms both objects and produce a strong enough ikata.
IV. Laser welding.
In 1955 the physicists succeeded in finding a laser beam, is simply to say rays produced at a specific wavelength and parallel, then enlarged, the rays are then focused. Heat generated at the point of focus is very high. By the year 1970, the laser started to apply the base pad, the laser as a light can be adjusted accurately so that the laser welding sangatsesuai for special equipment. Laser welding can be used to weld objects with a thickness of 0.13 mm to 29mm in shear velocity ranged from 21 mm / sec to 1.2 mm / sec. The question that arises pad base laser welding as well as electrons, the workpiece is very small gaps between 0.03 to 0.15. Until at this time a lot of classification methods used in the field of welding, it is because there needs to be agreement in terms of those things. In conventional methods such classifier vpada this time can be divided into two groups, namely the classification based on the work and the classification based on energy used.
