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.

Classification of Electric Welding Process

Electric welding with Carbon Electrodes, for example: an electric appliance with a single blast of carbon electrodes with an electric double carbon electrodes. On the electric base with carbon electrodes, the electric arc occurring between the end of the carbon and metal electrodes or between the two ends of the carbon electrodes to heat and melt the metal to be welded. Can be used as an ingredient added to the flux electrode or electrodes are webbed.

1. Electric welding with metal electrodes, for example:
2. Welding with electrodes webbed
3. TIG welding (Tungsten Inert Gas)

4. Submerged electric welding.
5. Welding with electrodes webbed

This electric welding electrode webbed as additives.
Electric arc occurring between the tip electrode and the base material will melt the tip of the electrode and the used base material. Membrane electrode that also burns will melt and produce a gas that protects the tip of the crater welding electrodes, an electric arc to the effects of outside air. Liquid membrane electrode which will freeze the surface of the weld stop up that also serves as a protection against external influences.
Electric arc temperature difference depends on where the measurement point, eg, the electrode tip temperature of 3400 ° C, but the workpiece can reach temperatures of 4000 ° C.

Electric TIG welding
TIG welding (Tungsten Inert Gas = Noble Gas Tungsten) using a tungsten electrode which is not an added ingredient. Electric arc between tungsten electrode tip and the base material is a heat source, for welding. Melting point of tungsten electrode is so high up to 3410 ° C, so that did not participate in the event of melting electric arc.
Electric rod equipped with a ceramic nozzle to protect the throwers protective gas welding area from the outside at the time of welding.
Most of the added material is used without the membrane electrode is moved and brought to the arc between tungsten electrode base material.
Argon used as a protective gas, helium or a mixture of both gases is that of usage depending on the type of metal to be welded.
TIG welding rod is usually cooled with less water circulating.

TIG welding burner consists of:
Submerged electric welding is usually automatic or semi-automatically using the flux powder for the protective effect of outside air. An electric arc between the electrode tip and the base material in the pile so that no ray flux welding out as usual on other electric welding. Welding operator does not need to use a glass eye protection (welding helmets).
At the time of welding, flux powder and frozen and will melt coating welded shut. Most of the flux powder which melts not be used again after cleaning of the slag-slag welding.
Electrode which is a coil-shaped wire vacum membrane (roll) is moved forward by a couple gears are rotated by an electric motor ean be arranged according to the needs of the welding speed.

Electric MIG welding
As with any electrical pedestal pad TIG, MIG power base pad is also heat generated by an electric arc between two electrons and the base material.
Electrode is a wire coil which moves in the form of rollers arranged by the couple gear-driven electric motor. Movement can be adjusted as necessary. The shaft is equipped with a nozzle weld metal to connect the protective gas is supplied from the gas bottle through the gas hose.
CO2 gas is used for welding mild steel and steel. Argon or a mixture of argon and helium for welding aluminum and stainless steel. MIG welding process is semi automatic get or automatic. Semi-automatic welding meant manually, while the automatic welding is carried out entirely automatic.
The electrodes exit through the stalks together with a protective gas.

Electric current
At this current, the electrons move along the conductor in one direction only.
Direction of flow of alternating current is sinusoide wave intersecting the zero on the time interval 1/100 second for a machine with a frequency of 50 hertz (Hz). Each cycle consisted of half-wave wave of positive and negative waves some middle. Alternating current can be converted into direct current by using a flow modifier

Classification Welding & Cutting

Up to this time a lot of classification methods used in the welding field, is due to the agreement in such matters. 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. The first classification divides molten weld in the welding, welding press, welding and other welding. While the second classification distinguishes the groups such as welding, chemical welding, mechanical welding and so on. If a more detailed classification is held again, then both of the above classifications will be mixed and formed groups are aplenty. Between the two ways of classification mentioned above classification seems to work more widely used because it is the classification described in this chapter are also based on the way to work. This classification is based on the wel ding can be divided into three main classes, namely: Liquid welding, welding and soldering press.Welding welding how in which the liquid is heated to melt the connection with the heat source of an electric arc or gas flame burning sources.

1. Welding welding press is the way in which connections are heated and then pressed up into one.
2. Soldering welding is the way in which the connection was tied up and put together programs so use a metal alloy having a low melting point. In this case the parent is not involved melting metal. Cuts are discussed in this book is how to cut metal that is based on a cut metal melt. Way that is widely used in welding and cutting with oxygen gas by the electric arc cutting. Welding is the most widely used at this time is a liquid with arc welding gas.

Up to this time a lot of classification methods used in the welding field, is due to the agreement in such matters. 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. The first classification divides molten weld in the welding, welding press, welding and other welding. While the second classification distinguishes the groups such as welding, chemical welding, mechanical welding and so on. If held longer and more detailed classification, then the two classifications above and will form groups are aplenty. Between the two ways of classification mentioned above classification seems to work more widely used because it is the classification described in this chapter are also based on the way to work.

This classification basic welding can be divided into three main classes, namely: Liquid welding, welding and soldering press. Welding manner in which the liquid is heated to melt the connection with the heat source of an electric arc or gas flame burning sources. How welding press is where the connection is heated and then pressed up into one. Which soldering welding connection is tied to and incorporated programs so using a metal alloy having a low melting point. In this case the parent is not involved melting metal.

Cuts are discussed in this book is how to cut metal that is based on a cut metal melt. Way that is widely used in welding and cutting with oxygen gas by the electric arc cutting. Welding the most used at this time arc welding with gas liquid. Because it both ways, namely electric arc welding and gas welding will be discussed separately. While welding ways that would otherwise be grouped in a single subject. Cutting, because it is a separate issue then the discussion is also carried out separately. Below is the classification of the welding means:

a) Welding of liquid

1. Gas welding
2. Electric welding slag
3. Electric welding gas
4. Thermic welding
5. Electron electric welding
6. Plasma arc welding

b) Welding press

1. Electric resistance welding
2. Welding point
3. Sectional welding
4. Arc welding press
5. Press welding
6. Blunt press welding
7. Press the gas welding
8. Wrought welding
9. Friction welding
10. Explosion welding
11. Induction welding
12. Ultrasonic welding

Various types of welding processes

There are various types of welding processes and each has its own advantages and disadvantages, including:

1. Arc welding is a technique that uses the power supply and create an electric arc between the electrode and the base material.
2. Forge welding is a process that joins metals by heating them to high temperatures.
3. Tig tungsten electrode to produce weld and it is another name for gas tungsten arc welding of metals and used for thin sections of stainless steel and non ferrous metals.
4. Mig welding is automated arc welding process for its versatility and speed and the welding of aluminum and non ferrous materials.
5. Spot welding is a process in which metal surfaces are joined with the heat obtained from resistance of current flow.
6. Gas welding is also referred to as oxy-fuel welding and gas used for welding and cutting metals.
7. Stick or shielded metal arc welding is a process that uses manual arc consumable electrode.
8. Arc plasma using a plasma gas and has a narrow penetration with a greater concentration of energy.

Constraints on Underwater Welding

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

1. Class, either DNV or have not received LR technique for permanent repairs. There are weld defects which almost always accompanies (porosity, lack of fusion, cracking) these burdensome welding technique for permanent improvement purposes. On improving elements that can be said to be less important, the class was able to accept it as a conditional permanent which can be considered as a permanent home in the next inspection found no significant reduction of quality welding.
2. AWS D3.6 refers to: 1999 Specification for underwater welding, namely, the best results can be obtained from this technique is a new Class B. Results like this can only be acceptable if only for the purpose welding applications that are less important / critical 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.
3. The high risk of hydrogen cracking in the HAZ area, especially for material that has higher levels of carbon equivalent of 0.4%. Especially in the North Sea, offshore structures used to use this material.
4. Based on existing experience in the industry, welding technique is only performed up into no more than 30 meters.
5. Shielded metal process performance arc (SMA) of ferritic electrodes deteriorate with advancing into. Commercial producers also limit the use of electrodes to a depth of 100 meters.
6. The nature of the welding results also deteriorated with increasing depth, especially for small ductility and toughness (Charpy impact).
7. 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 air. When the flow is retained, there will be a risk of explosion is usually harmful to divers.

Welding technique electric current

SMAW welding is a technique by using an electric current flow and arc-shaped electrode webbed. Other types of arc welding with an electric current is SAW submerged arc welding, gas metal arc welding GMAW-MIG, gas tungsten arc welding and plasma arc G. This Occurs in the SMAW welding electrode gas when it melts wrap membrane, so the process is not required pressure / pressure inert gas to displace the oxygen or water can cause corrosion or bubbles in the weld-weld. Prose welding Occurs Because the electric current flowing Between the electrodes and welding material forming the heat so it can reach 3000 ° C, Thus Spake making the electrode and the material to be welded to melt. Based on its current type, welding is Divided into AC and DC current, the which flows straight polarity DC-Divided into direct and reverse polarity polarity - polarity reversed. Welding machine was Divided into two types, namely constant current - constant voltage and current fixed - fixed voltage, which in any arc welding electric current in the event of an enlarged bow will lower and raise the voltage and current in the shortened arc current will increase of and Decrease voltage.


To get a good weld should:

1. Appropriate electrodes using
2. Appropriate type of current
3. Type of polarity is correct for the DC current
4. Avoid left-right movement during welding welding
5. Short form of the arc current, welding doing a steady and regular
6. The rate of welding electrodes in accordance with the speed of the melt.

Often the problems That Arise in the arc welding current is:

1. Electrode freezes / stops welding
2. Form an ugly seam welding
3. Arc welding current is bad Because It expands
4. Moderate membrane electrode / flux is made Generally dariserat
5. Wood / cellulose
6. Titanium oxide
7. + Titanium base compound
8. Mn + Fe + Si
9. Iron oxide
10. CaCO3, the which will form the type of electrode in the form type: E, R, ER, EC, EW, B, RB, RG and F.

Selection of electrodes is based on:

1. Properties of the materials to be welded
2. Welding position
3. Connection type
4. Number of welding
5. Density of the welding connection
6. Current types are available.

AC welding machine
Electrical machinery classified AC DC welding machines and welding machine, welding machine, air conditioning is usually a welding transformer, welding machines DC while besides transformers equipped with a diode rectifier or (Changer alternating current into direct current) motor drive Typically uses either diesel or petrol motors and electric motors. That AC welding machine uses a transformer or welding transformer.

Currently Widely used welding machines DC Because DC has
some of the advantages of the AC welding machine, Such as arc stability,
polarity can be set.

Welding DCSP (Direct Current Straight Polarity) or welding Straight Polarity.
If the base material or the material to be welded is connected to the positive pole (+) and the electrode connected with negative polarity (-) on the DC welding machine in this way is called straight polarity welding or DCSP.

In this way the electric arc moves from the electrode to the base material so That the collision of electrons in the base material resulting in 2/3 heat in the base material and the third heat in the electrode. This method will result in melting of the base material so That more than the electrode results have deep penetration welding, so That both are used in welding a slow and narrow weld bead and for a thick plate. Welding DCRP (Direct Current Reversed Polarity) Welding or reverse polarity. With the welding process in this way connected with the base material of negative polarity (-) and the electrode connected with the positive pole (+) of DC welding machine, and so-called DCRP arc moves from the electrode base material and the electron collision resulting in electrode 2/3 heat at the electrode and the third heat in the base material.

This method will Produce more That so the melting electrode has a shallow penetration welds, and both are used in welding of thin plates with the weld bead width.

Welding AC (alternating current) or alternating current to alternating current electric welding there is no positive and negative poles (two both the same) and therefore the connection behind the inverted REMAIN the same results. Each pole will receive 50% of heat penetration and consequently normal.

Electrode welding
Most of the SMAW welding electrode coated by a layer of flux, the which serves as a gas-forming fluid That Protects the metal from the surrounding water Contamination. In Addition fluk also useful for forming weld slag That also serve to protect the weld from the air surrounding liquid. Electrode layer is a mixture of chemicals That the composition as needed welding. According to the AWS (American Welding Society) electrodes are classified with the letter E and Followed by four or five digit Following E. The first two digits or three digits indicate tensile strength welds three digits indicate
over 100 000 psi tensile strength while the two digits indicate the weld tensile strength of less than 100 000 psi. For example, electrode E 6013 has a tensile strength of 60.000 psi (42 Kg/mm2). While the third or fourth digit figure for a Greater tensile strength 100 000 psi (70 Kg/mm2) next digit position of the welding point, if the numbers mean for all positions. Welding 1, number 2 means the weld flat horizontal or l and 3 show for the welding flat. The last digit indicates the type of chemical mixture of the electrode layer.

Electrode welding mild steel & alloy

Here is given a list of conditions for mild steel welding electrodes and low alloy steels Philips.

Electrodes for Cast Iron Fitting
Electrode used for welding cast iron is as follows:

Steel electrodes
Electrodes of this type when used for welding cast iron will Produce a strong weld deposit so it can not be machined. Thus Spake the electrode is used when the welding is not done anymore. To weld cast iron with steel electrodes can be used AC or DC welding plane poles reversed.


Nickel electrode
This type of electrode used for welding cast iron, when the welding is done again with the machine. Nickel electrode can be used in the sense of seeing the welding position. Ridge welding electrodes are produced in cast iron is flat and smooth when used in DC welding plane poles reversed. Characteristics of the nickel electrode can be seen in the table below.

Bronze electrodes
Welds by means of electrodes are resistant to cracking, so the length of the weld can be added. Core wire of the electrode is made of phosphor bronze and given a membrane That Produces a stable arc.

Electrodes for Aluminum.
Aluminum can be welded with electrodes made electricity from the same metal. The selection of aluminum electrode in accordance with the work table is based on information from the which the factory makes. Aluminum electrodes AWS-ASTM AI-43 for electric arc welding is a welding plane pole upside down where the use of DC currents expressed in the following table

Membrane Electrodes for Hard
Objectives in terms of hard coatings are conditions for use of equipment or materials are resistant to scraping That, punch and wear resistant. For this purpose the electrodes for hard coatings can be classified into three types are:

Scraping the electrode resistance.
Electrodes of this type are made of chrome carbide tube filled with carbide Filings. Electrodes with a diameter of 3:25 mm - 6.5 mm is used bicycles AC or DC welding plane poles reversed.
These electrodes can be used for hard coatings on the surface of a thin slice, expand the holes and some type of knife.

Electrode resistance blows.
These electrodes can be used on AC or DC welding plane poles reversed. Hard coatings used for the solver and a hammer.

Wear-resistant electrode.
These electrodes are made of non-ferrous alloys containing Cobalt, Wolfram and chrome. Usually used for hard surface coatings and the exhaust valve and valve seat wear in the which the temperature is very high.

ARC Welding Machine Electrode

Electric arc welding electrode is encased in one of the electrical arc welding electrode feed, the the which uses an electric arc as a source of heat. The heat That Occurs in electric arc occurring Between the electrode with the workpiece, melting the tip electrode (wire) welding employment and local bodies, then form an alloy, solidifies into welds (weld metal). Wrap (which serves as an electrode flux coating will burn in time process, and the gas Occurs That will protect the process to the influence of outside water. Fluid will wrap on the surface of the weld solidifies and floats called slag, the the which can then be cleaned easily.

WELDING MACHINE (WELDING MACHINE).
Requirements of the SMAW process is a continuous supply of the electric current (electric current), the number of ampere and voltage stability of the welding flame is quite good (Arc) will REMAIN intact.

Where electric power (electric power) obtained from the welding machine by type currents are issued 3 (three) types of machines namely:
a. Machine with direct current (DC).
b. Machine with an alternating current (AC)
c. Machine with a combination of the direct current (DC) and alternating
(AC)
Machine on direct current (DC) equipped with the changing nature of alternating current component (AC) into direct current (DC) is a generator, Because That Is the electric current used here not from the battery, but the emergency power generator.

Alternating current machines do not need to be equipped with a generator, a transformer, but enough. Electric characteristics 80-85% efficiency. For a combination of AC and DC machine is equipped with a transformer and rectifier, the rectifier is the which has a function to smooth the flow.

Selection of Welding Parameters
The length of the arc (Arc Length) is Considered to be either more or less the same with him. electrode is used. Magnitude of the voltage used for welding every position not the same. For example he was. electrode 3 mm - 6 mm, has a voltage of 20-30 volts in flat position, and this voltage will be reduced Between 2-5 volts at a position above the head. Voltage stability is greatly Determines the quality of welding and also stability through sound during welding. The amount can be heard also affect welding current, wherein the amount of electrical current depending on the welding of the material and size of welds, the geometry of the welding connection, and he's kind of electrode. core electrode. For welding in the weld area has high absorption capacity That Necessary heat and large electric currents may also need additional heat. Moderate for steel welding alloys, the the which can be easily hardened his HAZ region too fast cooling effect, cooling it to withstand these high heat input is given to a large welding current. Welding of metal alloys, in order to avoid burning the element should be used alloying elements welding current is as small as possible. Also on the hot weld cracking may occur, for example, in austenitic stainless steel weld the use of heat so it cultivated as small as possible must small. Welding speed of the welding current depends on the parent material, type of electrode, he. Core electrode, the geometry of the connection, the connection accuracy. Necessary in order to more higher welding currents can Quickly.

Electrical polarity affect the outcome of an electric arc. Electric Properties on the arc direct current (DC) will be more stable than the alternating current (AC). There are two types of polarity is the polarity of the straight, where the object of positive and negative working electrode (DCEN). Reverse polarity is the reverse polarity ie the opposite. Characteristics of metal removal Occurs by ejection, then this polarity mepunyai more results in the than welding with straight polarity (DCEN).

Welding Implementation
Ignition of the arc welding can be done by performing a brief relationship with the parent metal electrode tip, and then separate them again until a Certain distance as the length of the arc. Where the normal arc length Between the the which is 1.6 - 3.2 mm.

Electric arc outages done by removing the electrode from the parent material. to Produce a weld bead connecting the well can be performed as follows:
Before the electrodes should be kept away from the parent metal arc length reduced first, then the electrode was kept in a position to more adequately tilted.

Movement of Welding Electrode
There are different Airways to stimulate the (swinging) welding electrode, namely:

1. Electrode is driven by forward and backward, this method is one form of weaving methods.
2. Other forms of weaving is to make a move like and a half months.
3. Electrode That resembles a figure 8 motion.
4. Electrode with a rotating motion.
5. Electrode movement by forming hesitation.

All movements have a purpose to get a deposit weld metal with a flat surface, smooth and protected from the notch and Including slag, slag, the most Important in the movement of the electrode is the precision of angle and speed stability. Swing-shaped electrode for welding or bending webbing width of weld bead welding is limited to 3 (three) times as large as the diameter of the electrode.

Welding Techniques for Groove Connection Type

Flat position (1G)
It is recommended to use methods Such as figure 9 A and B. This can be done to kind of connection penetration on both sides, but can also be done on one side only penetration. Type a flat position (1G) in the implementation very easy. Pipe material may be applied on the road playing the pipes.

Horizontal position (2G
2G welding pipe welding positions are horizontal, upright position to the pipe and welding Carried horizontally around the pipe. Difficulty horizontal position welding is the weight of the liquid weld itself it will always be down. The angular position of the 2G pipe welding electrodes is 90 º. The length of the electrode movement Between 1-2 times the diameter of the electrode. When too long can lead to lack of good quality weld. Arc length in
short as possible try ½ times the diameter of the welding electrode. For the welding of filling made with a circular motion and Attempted to burn well on both sides of the seam so as not to occur ACAT. This movement is repeated for the next replenishment.

Vertical position (3G)
3G position welding done on the plate material. 3G is Implemented on a vertical position and the electrode plate. Difficulty of welding is similar to the 2G position due to the gravitational force of the liquid electrode welding.

Pipe welding in 5G position welding can be Divided into up
and welding down. Welding up is usually performed on the pipe wall has a high thermal Because It requires a teal. Speed ​​up the welding direction to the direction of welding is lower than down, so the heat input per unit area is higher than the 5G welding pipe welding down. The position placed on a fixed horizontal position and the welding done around the pipe. So That the welding
well, it is Necessary to weld studs (tack weld) on 5-8-11 and 2 o'clock position. Start welding at 5:30 to 12:00 hours through 6 hours and then Followed by the 5:30 o'clock position at 12:00 over 3 hours

Movement of the electrode to pass root position (weld root) is regular at a distance triangles ½ times the diameter of the electrode arc.

Welding down
Usually done on a thin pipe and oil pipelines and natural gas. The reason the use of welding down more lucrative dikarenakanlebih faster and more economical.