Electric Arc Welding Technology

Electric Arc Welding

For centuries wrought las used as the primary process to connect the metal without much experience growth. In the early 19th century, found a new way, namely electric arc welding flame (Electric Arc Welding) with a carbon rod electrode without the wrapper by using the battery as a power source. The main weakness of electric welding process is the oxidation of carbon is high relative to the weld (weld easily rust) so that the welding is widely used.

At the same time, in 1877, found weld resistance (Resistance Welding). A British physicist, James Joule, recognized as the inventor. In 1856 he heat up two pieces of wire with electric current. During the heating process, the wires are pressed to each other. It turns out the two wires are tied to each other after heated.

In further development, resistance welding produces several types of welding processes, eg welding flash (Flash Welding) in the electrical resistance 1920. Welding achieve glory of being created different types of robots. Developed to meet the needs of the various forms of electrical resistance welding includes welding point, interval, seam (line) and projection. Welding Process implement this in the heat and press. Electrode serves as a channel for the flow and pressure plate-shaped workpiece.

In the next decade, introduced last hermit (Thermit Welding) by adding a chemical process is repertoire welding technology. Welding termit by pouring molten metal between two metal end which would be connected so it would melt. After freezing the fused metal and liquid metal is poured to function as an added ingredient.

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 repair is shifted by the electric arc welding in which welding arc is wrapped electrode wear. After the fire, wrapping electrode produces gas and slag. Gas protects the weld crater of oxidation during the welding process is underway. Protect the weld slag during the freezing process to cool (until the slag is cleaned). Limitations of arc welding electrode rod is limited so long electrode any given period should stop changing the welding electrode. More material efficiency is far from 100% because I had no butt.

Starting from this weakness was then in the late 1930s created an arc welding electrode coils. In principle, the welding is not necessary to stop before reaching the end of the weld line. And welding can be done by automatic or semi automatic. Used as a protective flux. Flux outlined shortly in advance so that the electrode electric arc flame hidden by the flux. Advantage, the operator is not dazzled by the flame of an electric arc, weakness, limited to the welding position just under the hands of the other positions scattered flux will fall before the function.

In 1941 in the United States found Tungsten electrode. Tungsten is not melted by the heat of the flame of an electric arc that does not feed in the weld. Core is used as a protective gas (Inert) which can persist for some time on his condition. Core gas ejected stricken welds so the welds protected from oxidation. Because it uses the core as a protective welding welding is often called TIG welding (Tungsten Inert Gas).

The successful use of gas tungsten core pad pad pad pad electrode also tried the roll in the early 1950s. This process is hereinafter referred to as Gas Metal Arc Welding (GMAW) or MIG welding (Metal Inert Gas). Because metered gas is very expensive then used a mixture of argon and oxygen gas or CO gas is quite active. Welding is commonly called the 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.

Found the next arc welding electrode welds with a protective roll floured. In order to be used in all positions, such as perforated pipe electrodes are made to put the flux. The process is relatively cheaper than gas arc welding, it can be to any position and can be developed technical welding semi-automatic or fully automatic welding is called the flux cored arc welding electrodes (Flux Core Arc Welding) electrodes Then there are the components to be mounted on the other. This is called weld stud welding. Stud mounted on the main body through three stages, namely the setting position, the search ends and the main body studs and stud pressure on the main body shortly after the arc flame is turned off.

After that developed electric welding high frequency is 10 000 to 500 000 Hz. High-frequency electric welding is often called induction welding. Judging from the unification process of the workpiece, solid welding including welding aided by heat to break down a layer of oxidation or dirt on the surface of the workpiece. Produced heat the workpiece surface is very thin so it is suitable for welding thin plate.

In the 1950s, transforms electrical energy into a beam of electrons fired from the workpiece. Greater the heat generated and the dimensions of the former electron is much smaller than electric arc flame, welding very quickly so it is suitable for mass production. Hot region becomes more narrow so it is suitable for materials sensitive to thermal changes. Excellent weld quality and accuracy, it's just very expensive equipment. This method is called las electron (Electron Beam Welding).

Scratch Welding
In 1950, AL Chudikov, a mechanic from the Soviet Union, put forward its observations on the theory of mechanical power can be converted into heat energy. Friction that occurs in the engine parts that move caused many losses as partly generated mechanical power turns into heat. Chudikov argue, so the bias should be used in the welding process. After going through a trial and he succeeded in welding research by utilizing the heat caused by friction. To increase the heat that occurs, the workpiece is not rotated but only pressed one against another. Pressure also serves to accelerate fusion. This is called friction welding (Welding Friktion)

Plasma Welding
Electric arc plasma flame welding (Plasma Arc Welding). Plasma process is an improved welding tungsten actually, it's just an electric arc burning between the electrodes do not appear to work but the object appears between the tip electrode with the gas flowing around the core. Welding plasma was better than tungsten because of arc welding flame that appears more stable power with a smaller diameter so that the heat is more concentrated. Faster welding process bias, in addition to tungsten never touch the workpiece.

Sound Welding
Earlier in the year 1960 was marked by the discovery of welding that uses high frequency sound (Ultrasonic Welding). It also uses an electric welding process works, there is no power at the workpiece, the heat generated merely the result of processes and it is only helpful in the process of unification of the workpiece.

Voice used ranged from 10 000 to 175 000 Hz, the sound vibrations transmitted through electrode mounted on the workpiece. Then pressure is applied to the workpiece during the process. Advantages of this process is suitable for thin objects and not affected the type of material to which you connect. Not wearing thermal energy as the primary energy is its own advantages in certain materials and thin, it's just less work for the 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.

Explosive Welding (Explosive Welding or EXW)

Explosive Welding (Explosive Welding or EXW) was developed from the observation of one's days of World War I, there are fragments of a powerful bomb attached to the other metals fell. Carl's research conclude that shrapnel is attached because the effects of jet in the event of collision. The effects of jet capable of cleaning dirt on the surface of the object so that it contacts between atoms both objects and generate a strong enough.

Laser Welding.
In 1955, the physicists found laser beam, simply speaking rays produced at a particular wavelength and parallel, then enlarged, light is then focused. The heat generated at the focus point is very high. By the year 1970, the laser began to apply the base pad, as the laser beam can be accurately adjusted so that the laser welding very suitable for special equipment.

Laser welding can be used to weld objects with a thickness of 0.13 mm to 29mm at the sliding speeds ranging from 21 mm / sec to 1.2 mm / s. Issues arising pedestal pad as well as laser welding electron, the workpiece is very small rift between 0.03 to 0.15. Up at this time a lot of classification methods used in the welding field, is due to the agreement in terms of these things. In the conventional ways of classifying these at this time can be divided into two groups, namely the classification based on the work and the classification based on energy use.

Basic Electrical Welding Technique

The principle of electric welding

Joining two or more pieces of metal together by melting or burning the search with an electric arc as a source of heat. The use of electricity as a source of light is divided into two:

1. Electric resistance welding
2. Electric arc welding flame


Electric resistance welding is a welding process will be undertaken by an electric current flows through the fields or the surface of the workpiece to be on the dial or the welding. Prisoners in the electric current will arise in the fields of touch and useful heat will cause the surface of the melt grafting. Thus, the pressure exerted between the two materials will cause a blend of work between the two pieces are connected. While electric arc welding is a welding flame that is done by changing the electrical current into heat to melt or melt the surface of the object to be spliced ​​and generate electricity through the flame arc electrodes. The occurrence of an electric current is caused by the voltage difference between the two poles of the work and electrode. This voltage difference is called voltage arc flame.
This voltage large between 20 volt and 40 volt

b. Electrode
Electrodes is an important part in the electric arc welding. During the welding electrodes will expire at on welding. Will affect the types of welding electrodes, so that the selection and type of elektrode be appropriate. Based on the protective film can be divided into two kinds of electrodes and electrode webbed plain.

Webbed electrode consists of the core and the protective or flux. Coating flux coating done with the way in spray, dip or destrus. Her purpose in this flux to the electrode when burning will produce co2 gas welding in order to protect the liquid, an electrical arc of oxygen that can undergo oxidation so that the weld material will affect the nature of the mechanism of the weld metal.
So the membrane electrode has functions such as:

1. Prevent formation of nitric oxides and metal during the welding process takes place.
2. Creating a protective shaft so as to reduce the speed of cooling, with the aim of the welded workpiece does not have brittle or fragile.
3. Provide specific properties of the weld by adding certain substances contained in the membrane.
4. Stabilize the arc and the arc flash drive so easy to control.

Hence the choice of electrode should be appropriate to consider the following.
• Type of weld metal to be in
• Thickness of material to be welded
• mechanical strength that is expected from the welding
• Outstanding welding and
• The seam of the workpiece

Scope and Definition of Welding

Definition of welding according to the American Welding Society, 1989

Welding is the process of metallic or non metallic connection made by heating the material to be connected to the welding temperature is carried out: with or without the use of pressure (pressure), only the pressure (pressure), or with or without using a filler metal (filler)

Definition of welding according to the British Standards Institution, 1983
Welding is the process of switching between two or more materials in a plastic or liquid state using thermal (heat) or pressure (pressure) or both. Metal filler (filler metal) with a melting temperature equal to the melting point of the parent metal can be used within or without the splicing process.

Historians estimate that the ancient Egyptians began using welding with pressure in the year 5500 BC (to create by hammering sheets of copper piping that edges close to each other). Bendaseni Winterton said that the Egyptians made in the year 3000 BC consists of the base material of copper and gold smelting and beating results. This type of welding, which is called welding wrought (forge welding), is the first human effort in connecting two pieces of metal. Welding example is the famous ancient forging Damascus swords are made with forged iron layers of different nature.

Welding forging has evolved and important to the ancient Romans so that they refer to as a god Vulcan (the god of fire and metalworking) for the state of art. Now the word is used for retreading rubber with sulfur treatment process, but the first word means "hardened". These days welding wrought practically been abandoned and the last made by a blacksmith.

Years 1901-1903 Fouché and Picard developed a welding rod that can be used with acetylene (carbide gas), so since it began the era of welding and cutting oksiasetilen (carbide gas oxygen). Period between 1903 and 1918 was a period of use of welding mainly as a way of improvement, and the most rapid growth occurred during World War I (1914-1918). proven welding technique can be applied mainly to repair the damaged ship. Winterton reported that in 1917 there were 103 enemy ships in the U.S. are broken 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 evolve with the first electrode alloy (alloy) the copper-tungsten for welding point in 1920. In the period 1930-1950 occurred a considerable increase in the development of welding machines. Sunset flame arc welding process (submerged) the arc flame sealed under a 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 various metals and alloys.

Welding that we see today is much more complex and highly developed. Advances in welding technology is so rapidly until 1877. Prior to 1877, forging welding and soldering process has been used for 3000 years. The origin of the electrical resistance welding (resistance welding) began around 1877 when Prof. Elihu Thompson began experiments on the reversal of the polarity of the transformer windings, he received his first patent in 1885 and blunt the electrical resistance welding machine (resistance butt welding) was first exhibited at the American Institute Fair in 1887.

In 1889, Coffin was given a patent for welding flame blunt particles (flash-butt welding) welding process is a blunt one that matters. Zerner in 1885 introduced the flame carbon arc welding process (carbon arc welding) using two carbon electrodes, and NG Slavinoff in 1888 in Russia was the first to use the flame of metal arc process using bare electrode (without coating). Coffin also working independently investigate the flame of metal arc process and received a patent in the United States in 1892. In 1889, A.P. Strohmeyer introduced the concept of a coated metal electrode to eliminate the many problems that arise in the use of bare electrodes. Thomas Fletcher in 1887 wearing inflatable tube of hydrogen and oxygen are burned, and show that it can cut or melt the metal. At this present time welding technique has been used widely utilized in various fields. Wide use of welding technology due to buildings and machinery are made by means of welding techniques are becoming cheaper.

Some ways of welding rails

Rail transport reasons leading to the location of the manufacturer is usually cut into the rail tracks with a length of 25 m. To increase the convenience of the train that runs on top of the rail is connected. Connecting rails done in several ways:

Thermite welding
One common way is by thermite welding location so it can be a continuous rail. Welding using thermite welding using the chemical compounds of iron which is placed between the rails and then the material is reacted at temperatures up to dilute the chemical and connect the rails, the waste products of chemical reactions are then cut and trim the rails.

Electric welding flash / Flash Butt Welding
One other way that is used in welding the railway line is to welding flashes of electricity or in English is called "Flash Butt Welding", ie by approaching the end of the two pieces to be welded rails that have been given an electrical charge to the current very large, so when this happens there will be a flash of electricity that will heat up and melt the tip is brought near the second rail. Once the rails are brought near the second end of the incandescent and melts, the second rail ends together with a large pressurized (150 - 300 kg/cm3) so that the ends of two pieces of rail are fused and then leveled and smoothing when the rails are still glowing. The advantages of this method is not needed materials such as thermite welding, and the results of welded joints in the rails is more powerful than using thermite welding, weld flash but it takes a shorter time, which is only 15 minutes per point of welding, as compared to thermite welding that takes time 25-30 minutes per point of welding. However, this method is not very suitable and dangerous in Indonesia, because the electric current can flow on the rail to the other rail. Given the many rail lines in various areas are densely populated, sometimes there are people especially children are innocently or accidentally touching the rails were given an electrical charge that can pose a shock hazard.

Bolted connection
Fishplate between the two rails which are connected

This connection is used on a buffer called the fish plate is bolted to the rails to be joined. With such a connection will be felt at the time of running the train.

Find Welding Inspector Course

Welding Inspector is a technical field the which was Followed by many people after a high school diploma. Many students wish to join WHO this field of study will need to have Recognized the right welding. You can start early with the inspector holding your career, but the most common way to start right after you finish high school education.

To become a welding inspector, you need to find a school or institution where They teach courses wielding inspectors. The first place to look for it online, Because most of the welding inspector Offered program is now online. At first, you can pick up some demo classes to start, once you have done They are to choose a study module That suits you best.

Many online schools and colleges offer flexible study timings are designed for working students. As a welding inspector jobs over the practical hands on work, requiring more practical than theoretical studies. Must complete the online study some practical work That can be done under the guidance of a specialist welding it.

On the internet, you can find a variety of welding inspector course. Some degree the last three to four years, while others are short-term courses That you can do during a small period of time. It really depends on the students, how students Quickly grasp the information. The Internet is a big world and you can find many other Certainly welding inspector program and students, with whom you can collaborate and discuss.

Besides online, there are traditional Airways to learn welding inspector course, an increasingly Enrolled in school or college That teach these courses. This is the method That is much better and Easier to get certified welding inspector That you have to get before doing commercial work.

Find good schools and affordable can be difficult, to touch. You can ask questions and take some classes to determine whether the school is good for you or your local no. School should be your first priority, Because you will have the local experience and you will enjoy your studies there is more. Many of the welding inspector course you take here will have an impact on your future job or field of work, so it is Important That you learn best. Try to take a good value Because It can affect your work in the future.

By taking the certification and study it fully, you will not only understand the subject but also will gain insight on industry norms and how the industry works. Welding job is all about working with the industry and you should have enough knowledge about the industry before you actually Become part of it.

A welding certification will definitely help you Become better at what you are. This Will Provide The Necessary recognition after undergoing rigorous training and practice of welding. Your certification will help you in getting a job and will put you on top of non-certified person. Your future will definitely be encouraged as you will become a certified welding inspector.

Classes Welding School Canada

The best school is Canadian Welding: Welding of his best at his best, is a college of approved and registered private career in London, Ontario, under the law of private vocational schools. Welding at its best is in London, Ontario, is a professional registered and approved private sector in private universities' Career Act, 2005. " The Institute has provided training welders in 1988, is available. It is an accredited Canadian Welding Bureau (CWB) and Technical Standards and Safety Authority (TSSA) Test Centre. The school offers a variety of welding applications designed for your specific needs. These schools give tests, books, equipment and personal protective equipment. Welding At Its Best program: Development of Certification / Qualification Program-plant training and certification program update Welder Welder Maintenance Certification Training Best in class keeps them in three shifts per day, which took in 4.5 hours of continuous, flexible configuration. The courses will be highly qualified, experienced and certified welders have extensive practical experience is invaluable in providing work-related best practices for teaching students. Those who successfully complete the program for the Canadian Welding Bureau (CWB) and the Technical and Safety Authority (TSSA) Certification tests to qualify. The classes are encapsulated in a short course, technical Maor long + four-welding machine, which lasts 48 weeks. For maximum CWB Welding Test Center, the fully certified CWB position for those who qualify in the welding process, such as shielded metal arc welding (stick), offers welding (MIG) arc movement of the flow (flat on the plate). Available for those (qualifying carbon steel or TSSA certification or tube collectors) for manual metal arc welding (STICK) (on the plate or pipe), welding, metal inert gas (MIG) (plaque), tungsten inert gas welding (TIG), and arc welding animation (horizontal).

April Welding Academy is located in Sault Ste Marie. Marie, Ontario, is a private vocational school act, registered in private vocational schools. April Academy offers courses as welding, shielded metal arc welding, oxyacetylene welding / cutting gas structural blueprint reading, advanced models of shielded metal arc welding, design and layout, welding tungsten arc welding and inspection and testing.

CWB Group is located in British Columbia offers a variety of courses for the inspection of welding, welding inspection, health / safety and other industry-related courses. The CWB claims Groupl has trained over 20,000 students as interns. It also offers tailor-made courses. General Welding School is located in Toronto, Ontario, founded in 1935 and aims to be the oldest school in Welding Canada. General Welding School One-on-one approach provides for the study under the guidance of professionals and skilled welders. General Welding School offers no classes, but they are all kept in the field. These four core courses offered to the public school, an arc-welding, MIG welding is a semi-automatic, heavy-duty acetylene (gas), and heli-arc TIG.
E 'is useful?

Underwater wet welding techniques

Although the underwater wet welding techniques (in this case in question is wet welding) has been known since 1930, but in reality not many interested parties to apply as an Appropriate solution. There are Several benefits of this welding technique, Including the Relatively cheaper cost and preparation required is much shorter than with other techniques, but there are other Things That Must be Considered before Applying. This article will discuss about its application in the repair of offshore structures with a focus on the constraints and challenges. During the period of operation, offshore structures will require some intervention under the water for maintenance, repairs or changes Such as:

Strengthening structures for recertification WHO have exhausted its design life
Improvement due to design errors
Repairs due to damage Caused by:
Error during installation
Incidents, eg ship-groundings, storms, falling objects from the upper deck, etc.
cracks at the junction due to environmental conditions (waves, wind)
The Addition of the structure Because of changes in operations (riser clamp installation, caisson, etc..)
Anode installation

As Mentioned above That have not been many interested parties to implement these underwater welding techniques. It is evident That there are only 50 events under the water for repair welding of offshore structures were published during That the last 40 years, it's also a bit of information That is technique. The industry is still interested in using hyperbaric welding or mounting clamp even though it took preparation is more complicated and more expensive costs. Below are described some of the obstacles still exist That Make That the industry is still reluctant to use this technique, as well as some challenges if we want to use it. Interventions for the above, there are Several commonly used techniques Such as

Grinding out cracks

• Clamps
• Grout filling
• Hyperbaric welding
• Underwater welding

Constraints
The reluctance of the industry to use underwater welding technique is understandable considering the Following things:

Class, either DNV or have not received LR technique for permanent repairs. There are weld the which almost always accompanies defects (porosity, lack offusion, cracking) these burdensome welding technique for permanent improvement purposes. element is to repair the 'less important', classs can accept it as a conditional permanent Could be Considered a permanent home in the next inspection found no significant reduction of the quality of welding TSB.

AWS D3.6 refers to: 1999 'Specification for underwater welding', the best results can be obtained from this technique is a new Class B. Such results can only be acceptable if the purpose of welding That is only for the applications are less Important / critical applications where lower ductility, porosity is more, the discontinuities are Relatively more acceptable. If welding is used usually only applied for purposes That are 'fit for purpose' only.

The high risk of hydrogen cracking in the HAZ area, ESPECIALLY for That material has higher levels of carbon equivalent of 0.4%. Especially in the North Sea, offshore structures used to use this material.

Of experience in the industry, welding technique is only performed up into no more than 30 m.

Shielded metal arc process performance (SMA) of ferritic electrodes deteriorate with advancing into.

Commercial producers also limit the use of electrodes to a depth of 100 meters.

The nature of the welding results also deteriorated with Increasing depth, ESPECIALLY for small ductility and toughness.

Due to direct contact with water, the water around the welding area to boil and Becomes ionized hydrogen gas and oxygen. Most of the gas is fused into the HAZ area but most of the others will flow into the water. When the flow is retained, there will be a risk of explosion is usually harmful to divers.

RESOLUTION
Although there are Several obstacles That made the industry reluctant to use this welding technique, there are actually some of the restoration effort has been done That, both in technique and quality of welding electrodes, Such as:


Hydrogen cracking and HAZ hardness in the area can be minimized or avoided by the application of multiple temper bead (MTB). The concept of this technique is to control the ratio of heat (heat input) Between the layers of the welding bead. To control this heat, the size of the weld bead on the first layer should be 'adjusted' so That the minimum penetration into the material Could be obtained. Likewise for the second layer and so on. That there are three parameters affect the quality of welding in the application of this MTB, namely: the distance Between the temper bead, timescales and heat input welding.

Buttering technique can also be used primarily for materials with more than 0.4% CE. Electrodes butter use oxidizing agent electrode or electrodes have Thermit.

Usage of the electrode with the oxidizing agent, this agent will absorb hydrogen or oxygen gas is absorbed in Haz

Use of Thermit used. Electrode electrodes Could also be producing this type of high heat delivery and welding material (weld metal) are thereby slightly reducing the rate of cooling of the welding by the surrounding temperature, Causing a kind of post weld heat treatment process.

Nickel-based electrodes can not withstand the hydrogen to diffuse into HAZ area. unfortunately only a hardness in the HAZ area is still high and the welding quality is only good for up to 10 meters depth.

WE MUST DO
As Mentioned above, in Addition to lower cost, the most Important thing to Consider in the selection of underwater welding applications is the preparation of the brief. Equipment used for this work is similar to dry welding techniques. there are some Things to think about so That the application of underwater wet welding technique is more acceptable to the industry:

The Things Mentioned above to bridge shortcomings in the new underwater welding job proved to a depth of up to 30 meters. Welding institutions must be proactive to try new techniques for deeper waters.

Welding techniques depend on the ability of divers. That means even if the technique allows, welding can only be done up to a depth of 200 meters. Needs to Consider the use of automatic or mechanical techniques for deeper waters.