Responsibilities

• Responsible for Welding Inspection activity.
• Welding Inspector shall assist for developing new welding techniques, methods and procedures with the welders to enhance the productivity
• Ensuring that welding requirement, welder and welding activities are correctly specified and carried out in accordance to relevant codes, client specifications and contract standards.

Qualification and Requirements

• Minimum 3 years relevant welding inspector experience.
• Valid CSWIP 3.1 or 3.2 certificate or equivalent.
• Job will start immediate
• base in Singapore

Duration:

• 4 months contracts

Remuneration package :

• Salary is negotiable
• Shift rotations where rest day may not fall on Sunday
• 5.5 days week with overtime.

Should you are meeting and interested for the above welding inspector job, please forward your application and resume to bennyfong@connect-energy.com or fax @ +65-62934649 not later than 18 november 2008.

]]> http://www.introductiontowelding.com/welding-inspector-vacancy/feed/ http://www.introductiontowelding.com/tig/ http://www.introductiontowelding.com/tig/#comments Sat, 01 Nov 2008 10:00:34 +0000 admin http://www.introductiontowelding.com/?p=29 Tungsten inert Gas (TIG) is frequently referred to as GTAW (Gas Tungsten Arc Welding). TIG welding is a commonly used for high quality welding process. TIG has become a popular choice of welding processes when high quality, precision welding is required.

In TIG process an arc is formed between a non consumable tungsten electrode and the metal being welded. Gas is fed through the torch to shield the electrode and molten weld pool. If filler wire is used, it is added to the weld pool separately.

TIG Welding Benefits

• Good quality welds
• Free of Spatter
• Welds can be made with or without filler metal
• Precise control of welding variables (heat)
• Low distortion

Shielding Gases

• Argon
• Mix Argon Hydrogen
• Mix Argon Helium

The purpose of Helium is generally added to increase heat input (increase welding speed or weld penetration). Hydrogen will result in cleaner looking welds and also increase heat input, however, Hydrogen may promote porosity or hydrogen cracking.

GTAW Welding Limitations

• Lower deposition rates.
• Requires greater welder dexterity than MIG or SMAW welding
• Costly compare with SMAW

next post: welding inspector job

Early Ages of Welding
It was believed that the history of welding was started 2000 years ago. As examples in the Bronze Age, a small gold circular boxes were made by pressure welding lap joints together.

Egyptians and people in the eastern Mediterranean area learned to weld pieces of iron together during the Iron Age. Many tools were found which were made approximately 1000 before century. No certain record until the 19th century that welding, as we know it

today was invented.

Early 1800
The production of an arc between two carbon electrodes using a battery is credited to Sir Humphry Davy in 1800.

Edmund Davy of England is known with the invention of acetylene in 1836. In the mid-nineteenth century, the electric generator was invented and arc lighting became popular. During the late 1800s, gas welding and cutting was developed. Arc welding with the carbon arc and metal arc was developed and resistance welding became a practical

joining process.

1880-1900
Auguste De Meritens used the heat of arc for joining lead plates for storage batteries in the year 1881. It was his pupil, a Russian, Nikolai N. Benardos, working in the French laboratory, who was granted a patent for welding. He, with a fellow Russian, Stanislaus Olszewski, secured a British patent in 1885 and an American patent in 1887. The patents show an early electrode holder. This was the beginning of carbon arc welding. Bernardos’ efforts were restricted to carbon arc welding, although he was able to weld iron as well as lead. Carbon arc welding became popular during the late 1890s and early 1900s.

1890
C.L. Coffin of Detroit was awarded the first U.S. patent for an arc welding process using a metal electrode In 1890,. This was the first record of the metal melted from the electrode carried across the arc to deposit filler metal in the joint to make a weld. About the same time, N.G. Slavianoff, a Russian, presented the same idea of transferring metal across an arc, but to cast metal in a mold.

1900
in 1900 coated metal electrode was introduced by Strohmenger in Great Britain. There was a thin coating of clay or lime, but it provided a more stable arc. Oscar Kjellberg of Sweden invented a covered or coated electrode during the period of 1907 to 1914. Stick electrodes were produced by dipping short lengths of bare iron wire in thick mixtures of carbonates and silicates, and allowing the coating to dry.

Meanwhile, resistance welding processes being researched and developed, including spot welding, seam welding, projection welding and flash butt welding.

Elihu Thompson originated resistance welding. His patents were dated 1885-1900.

A German named Goldschmidt invented thermite welding that was first used to weld railroad rails In 1903,.

Gas welding and cutting were invented during this period as well. The production of oxygen and later the liquefying of air, along with the introduction of a blow pipe or torch in 1887, helped the development of both welding and cutting. Before 1900, hydrogen and coal gas were used with oxygen. However, in about 1900 a torch suitable for use with low-pressure acetylene was developed.

World War I brought a very tremendous demand for armament production and welding was pressed into service. Many companies sprang up in America and in Europe to produce welding machines and electrodes to meet the requirements.

1919
After the war I in 1919, American Welding Society as a nonprofit organization dedicated to the advancement of welding and allied processes was founded by twenty members of the Wartime Welding Committee of the Emergency Fleet Corporation under the leadership of Comfort Avery Adams.

Alternating current was invented in 1919 by C.J. Holslag; but it was not become popular until the 1930s when the heavy-coated electrode found widespread used.

1920
During the 1920s, various types of welding electrodes were developed. There was considerable controversy during the 1920s about the advantage of the heavy-coated rods versus light-coated rods. The heavy-coated electrodes, which were made by extruding, were developed by Langstroth and Wunder of the A.O. Smith Company and were used by that company in 1927. In 1929, Lincoln Electric Company produced extruded electrode rods that were sold to the public. By 1930, covered electrodes were widely used. Welding codes appeared which required higher-quality weld metal, which increased the use of covered electrodes.
automatic welding was introduced in 1920. It utilized bare electrode wire operated on direct current and utilized arc voltage as the basis of regulating the feed rate.

Automatic welding was invented by P.O. Nobel of the General Electric Company. It was used to build up worn motor shafts and worn crane wheels. It was also used by the automobile industry to produce rear axle housings.

During the 1920s there was considerable research in shielding the arc and weld area by externally applied gases. The atmosphere of oxygen and nitrogen in contact with the molten weld metal caused brittle and sometime porous welds. Research work was done utilizing gas shielding techniques. Alexander and Langmuir did work in chambers using hydrogen as a welding atmosphere. They utilized two electrodes starting with carbon electrodes but later changing to tungsten electrodes. The hydrogen was changed to atomic hydrogen in the arc. It was then blown out of the arc forming an intensely hot flame of atomic hydrogen during to the molecular form and liberating heat. This arc produced half again as much heat as an oxyacetylene flame. This became the atomic hydrogen welding process. Atomic hydrogen never became popular but was used during the 1930s and 1940s for special applications of welding and later on for welding of tool steels.

H.M. Hobart and P.K. Devers were doing similar work but using atmospheres of argon and helium. In their patents applied for in 1926, arc welding utilizing gas supplied around the arc was a forerunner of the gas tungsten arc welding process. They also showed welding with a concentric nozzle and with the electrode being fed as a wire through the nozzle. This was the forerunner of the gas metal arc welding process. These processes were developed much later.

1930
Stud welding was developed in 1930. The New York Navy Yard developed this method specifically for attaching wood decking over a metal surface. Stud welding became popular in the shipbuilding and construction industries soon.

The automatic process that became popular was the submerged arc welding process. This “under powder” or smothered arc welding process was developed by the National Tube Company for a pipe mill at McKeesport, Pennsylvania. It was designed to make the longitudinal seams in the pipe. The process was patented by Robinoff in 1930 and was later sold to Linde Air Products Company, where it was renamed Unionmelt® welding.

Submerged arc welding was used during the defense buildup in 1938 in shipyards and in ordnance factories. It is one of the most productive welding processes and remains popular today.

1940
GTAW or Gas tungsten arc welding began from an idea by C.L. Coffin to weld in a nonoxidizing gas atmosphere, which he patented in 1890.

The concept of GTAW was further refined in the late 1920s by H.M.Hobart, who used helium for shielding, and P.K. Devers, who used argon. This process was ideal for welding magnesium and also for welding stainless and aluminum.

Gas Tungsten process was perfected in 1941, patented by Meredith, and named Heliarc® welding. It was later licensed to Linde Air Products, where the water-cooled torch was developed. The gas tungsten arc welding process has become one of the most important.

The GMAW or gas metal arc welding successfully developed at Battelle Memorial Institute in 1948 under the sponsorship of the Air Reduction Company. This development utilized the gas shielded arc similar to the gas tungsten arc, but replaced the tungsten electrode with a continuously fed electrode wire. One of the basic changes that made the process more usable was the small-diameter electrode wires and the constant-voltage poser source. This principle had been patented earlier by H.E. Kennedy.

The initial introduction of GMAW was for welding nonferrous metals. The high deposition rate led users to try the process on steel. The cost of inert gas was relatively high and the cost savings were not immediately available.

1950
Lyubavskii and Novoshilov announced the use of welding with consumable electrodes in an atmosphere of CO2 gas in 1953. The CO2 welding process immediately gained favor since it utilized equipment developed for inert gas metal arc welding, but could now be used for economically welding steels.

The CO2 arc is a hot arc and the larger electrode wires required fairly high currents. The process became widely used with the introduction of smaller-diameter electrode wires and refined power supplies. This development was the short-circuit arc variation which was known as Micro-wire®, short-arc, and dip transfer welding, all of which appeared late in 1958 and early in 1959. This variation allowed all-position welding on thin materials and soon became the most popular of the gas metal arc welding process variations.

1960
Soon after the introduction of CO2 welding, a variation utilizing a special electrode wire was developed. This wire, described as an inside-outside electrode, was tubular in cross section with the fluxing agents on the inside. The process was called Dualshield®, which indicated that external shielding gas was utilized, as well as the gas produced by the flux in the core of the wire, for arc shielding. This process, invented by Bernard, was announced in 1954, but was patented in 1957, when the National Cylinder Gas Company reintroduced it.

The electroslag welding process was announced by the Soviets at the Brussels World Fair in Belgium in 1958. It had been used in the Soviet Union since 1951, but was based on work done in the United States by R.K. Hopkins, who was granted patents in 1940. The Hopkins process was never used to a very great degree for joining. The process was perfected and equipment was developed at the Paton Institute Laboratory in Kiev, Ukraine, and also at the Welding Research Laboratory in Bratislava, Czechoslovakia.

The first production of electroslag was used in the U.S. was at the Electromotive Division of General Motors Corporation in Chicago, where it was called the Electro-molding process. It was announced in December 1959 for the fabrication of welded diesel engine blocks. The process and its variation, using a consumable guide tube, is used for welding thicker materials.

Electrogas was introduced by the Arcos Corporation introduced another vertical welding method in 1961. It utilized equipment developed for electroslag welding, but employed a flux-cored electrode wire and an externally supplied gas shield. It is an open arc process since a slag bath is not involved.

A newer development of electrogas used self-shielding electrode wires and a variation uses solid wire but with gas shielding. These methods allow the welding of thinner materials than can be welded with the electroslag process.

Plasma arc welding was invented in 1957 Robert F. Gage invented. This process uses a constricted arc or an arc through an orifice, which creates an arc plasma that has a higher temperature than the tungsten arc. It is also used for metal spraying and for cutting.

The electron beam welding process was developed in France. J.A. Stohr of the French Atomic Energy Commission made the first public disclosure of the process on November 23, 1957. In the United States, the automotive and aircraft engine industries are the major users of electron beam welding.

Most Recently of Welding History
Friction welding which uses rotational speed and upset pressure to provide friction heat, was developed in the Soviet Union. It is a specialized process and has applications only where a sufficient volume of similar parts is to be welded because of the initial expense for equipment and tooling. This process is called inertia welding.

Laser welding is considered as the newest processes. The laser was originally developed at the Bell Telephone Laboratories as a communications device. Because of the tremendous concentration of energy in a small space, it proved to be a powerful heat source. It has been used for cutting metals and nonmetals. Continuous pulse equipment is available. The laser is finding welding applications in automotive metalworking operations.

Now days, welding is a commonly being used in many sector of industries such as offshore jobs, metal fabrication, civil work, electronic and even aerospace.

]]> http://www.introductiontowelding.com/welding-history/feed/ http://www.introductiontowelding.com/welding-processes/ http://www.introductiontowelding.com/welding-processes/#comments Fri, 17 Oct 2008 06:48:00 +0000 admin http://www.introductiontowelding.com/?p=22 There are many kind of welding processes available now days. Letter designation is commonly being assigned on each process for identification on drawings, tables, reference, etc. it is also include processes such as adhesive bonding, thermal spraying, and thermal cutting.

To distinguishes between welding processes grouped under “Brazing” and “Soldering” from “Arc Welding”, “Gas Welding”, “Resistance Welding”, “Solid State Welding”, and “Other Processes” is the Capillary attraction.

The international organization such as “American Welding Society or AWS” has made each welding process definition as complete as possible so that it will suffice without reference to another definition. AWS define a process as “a distinctive progressive action or series of actions involved in the course of producing a basic type of result”.

Refer to AWS, welding process is defined as “a materials joining process which produces coalescence of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone and with or without the use of filler material”.

Mode of energy transfer, base on AWS, has grouped as the primary consideration. Then a secondary factor is the “influence of capillary attraction in effecting distribution of filler metal” in the joint. Capillary attraction distinguishes the welding processes grouped under “Brazing” and “Soldering” from “Arc Welding”, “Gas Welding”, “Resistance Welding”, “Solid State Welding”, and “Other Processes.”

Table below will show the welding processes grouping included the letter designation for each process. The letter designation assigned to the process can be used for identification on drawings, tables, etc.

Above is a brief description about welding processes. Detail of each welding process will be on next post.

Welding is widely used by metalworkers in the fabrication, maintenance, repair of parts and structures. While there are many methods for joining metals, this is the one of the most convenient and rapid methods available.

What is Welding? It is a process or an operation for joining two or more parts, usually metals, by means of heat or pressure or both to its melting temperature, in such a way that there is continuity in the nature of the metal between the parts. So it can involve filler material or not.

For joining the materials or welding, for sure it will need energy source. There are many types of energy sources that can be use for welding such as gas flame, electric arc, laser, electron beam and friction.

Welding process has been developed for many different of atmosphere such as open air, underwater and space. All atmosphere where welding to be done will cause hazard such as burns, electric shock, eyes damage, fume, ultraviolet. And also the knowledge & technology developed during time to time rapidly.

Back to the first paragraph, since this blog is for sharing and posting any kind related to introduction to welding from basic welding to advance, hence we invite you for sharing your knowledge and very please if any expert may spare the time to post in this blog regularly for sharing knowledge.