CHAPTER ONE
1.0    INTRODUCTION
In the past with the necessary of metals it always seems impossible to join two metals together with grooving riveting, this idea leads to alternative of finding a lasting solution to the problem. This brought about the idea of a welding machine with a well laminated core and coil wound together to form a high rated transformer which is immersed in a can of oil.
Welding is the most economical and efficient way to join metals permanently. It is the only way of joining two or more pieces of metal permanently to make a single piece. Welding is vital to our economy.
It is even said that over (50%) of the gross nation product of the industries is related to welding in one way or the other. Welding ranks high economy industrial process and involve more science and variable than those involved in any other industrial process.
The electrode is either a rod that simply carried current between the tip of the tong and the work, or a rod or wire that melts and supplies, fill metal to the joint.
The basic arc welding circuit is an alternating current (A.C) or direct current (D.C) power source connected by a “hot” cable to an electrode, when the electrode is positioned close to the work piece, an arc is created across the gap between the metal and the hot cable electrode. An ionized column of gas developed to complete the circuit.
1.1    BREIEF HISTORY AND HISTORICAL BACKGROUND
Arc welding did not come into practice until much later. In 1802, “Vasily Petrov” discovered the continuous electric Arc and subsequently proposed its possible practical applications including welding. The French electrical inventor “Auguste Demeritens” produced first carbon arc touch, patented in 1881, which was successfully used for welding leading in the manufacturer of lead-acid batteries. In 1881-1882 a Russian inventor “Nikolai Bernardo” created the electric arc welding method for steel known as carbon arc welding, using carbon electrode. (Lincoln Electric 1994), the procedure hand book of arc welding, Cleceland Ohiho Lincoln Electric ISBN 99949-25-82-2. The advance in arc welding contacted with the inventor of metal electrode in the late 19th century by a Russian, “Nikolai Slavyanov” 1888 and an American, “C.L coffin”. Around 1900 A.P strotimenger released in Britain a coated metal electrode which gave more stable arc, in 1905 Russian scientist “Vladimir Mitevich” proposed the usage of three phase electric arc for welding.
In 1919 the alternating current welding was invented by “C.J Hoslag” not become popular for another decade. Competing welding process such as resistance welding and oxy-fuel welding were developed during this especially the later, faced stiff competition from arc welding especially after metal coving (known as flux) for the electrode to stabilized the arc and shield the base material from impurities continued to be developed.
The arc welding was not common until during world war I, welding started to be used in ship building in Great Brittan in place of riveted steel plates. The Americans also became more of accepting of the new technology when the process allowed them to repair their ships quickly after a German attack in the New York Harbor at the beginning of the war. Even in the good old days, Nigeria make use of forgoing whereby two pieces of metal are join together by heating them to a high temperature ant then hammering them together (forge welding).
In 1919 the British ship builder “Cammel Laird” started construction of merchant ship, the fillager, with entire welding hill, she was launched in 1921.
During the following decade, further advanced allowed for the welding of reactive such as aluminum and magnesium, this in conjunction with the development in automatic welding, alternating current, flux fed a major expansion of arc welding during the 1930’s and then during world war two after decades of development, was finally perfected in 1941 and gas metal arc welding followed in 1948, allowing for fast welding of non-ferrous material but required more expensive shielding gases. Using a consumable electrode and a carbondioxide atmosphere as shielding gas. It quickly becoming to most popular arc welding process , in 1957. The flux cored arc welding process debuted in which the self-shielded wire automatic equipment, resulting in greatly increased welding speeds. In that same year plastic arc welding was invented. Electro slag welding as released in1958 and was followed by it cousin, electro-gas welding in 1961.