CHAPTER ONE
- 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.
1.2 LITERATURE REVIEW
This write up is fully based on the method and ways of carrying out
welding work and construction of the machine. Welding is a fabrication or
sculptural process that joins material usually metals or thermoplastics, by
causing fusion, which is distinct from the lower temperature metal. Joining
techniques such as brazing or soldering which do not melt the base metal. The
value of welding as a standard method of joining metal was not fully
appreciated before world war one, then because of the need for speed of
production in every metal using and metal fabrication industry, the order of
welding processes came on their own. During and after world war two, the new
welding method were developed, which further increased speed and facilitates
the joining of the many special purpose alloys that were developed during this
period.
Limited in its early application to small or less important parts,
welding in the second half of the 20th century was employed in
fabrication too numerous to mention, such as ship, locomotives, rail and cars.
The petroleum industry is a classic example. The cutting edge of the bit used
to drill on wells consist of a hard weld metal fused to backing transportation
to and from refinery is via all welded transport iron material.
Whenever a piece of apparatus is intended to contain a liquid or gas, welding is the logical method of fabrication. As such, it has almost completely replaced other method. Welding as of course by no means of confined to wide application where leak tightness is involved. In the conventional body on frame automobile, there are some 8,000 to 10,000 resistance welds and up to 40ft of arc welding.