Welder World Blog

expertvillage asked:

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Welding Blog

native_gangsta15 asked:


Im going to be a welder i was just wandering

Welding Forum

Katie Kelley asked:


Welding is the joining of metals by applying heat, sometimes with pressure and sometimes with an intermediate or filler metal having a high melting point. The intermediate or filler metal that is used to join metals together is commonly referred to as a welding rod. Many welders use welding rods containing a high percentage of the element manganese.

Maganese is used in welding rods because it strengthens a metal as it is being fused by the welding process. When metals are heated and melted together, gas is produced. These welding gases are dangerous since welders are exposed to manganese when they breathe the fumes released in the air as rods are melted during welding operations. Manganese is a toxic element that passes quickly into the blood stream and tissues of the body.

Welders show a higher than normal average of manganese exposure. Manganese poisoning or exposure to high levels of manganese on a frequent basis or over long periods of time can lead to a disease known as manganism. Manganism is also known as welder’s disease. Some of the symptoms of manganism are very similar to those of Parkinson’s disease. As a result, manganism has been classified as a Parkinsonian syndrome.

Researchers found welders who had been exposed to manganese fumes in welding rods and materials were likely to develop side effects and symptoms of Parkinson’s 15 years earlier than an average individual not exposed to welding rod fumes. Both scientists and manufacturers of welding rods have known that there was a higher incidence of Parkinson’s disease and asthma among welders and other individuals exposed to manganese and other dangerous elements contained in welding rods. The manufacturers, however, failed to adequately warn of these ill effects, and for years have failed to instruct employers of welders on how they can keep their workers safe.

Health Effects of Welding Rod Fume Exposure

Manganese poisoning is one of the most documented of all complications caused by environmental toxins. Still, manufacturers continue to use manganese in welding rods and other applications, choosing to put profits before safety. Manganism is also known as Parkinson’s Syndrome because its symptoms are very similar to Parkinson’s Disease, a debilitating and incurable disease affecting the central nervous system and the important production of the neurotransmitter dopamine.

The symptoms of Parkinson’s Syndrome include tremors affecting various parts of the upper body, reduction of facial expression, difficulty in locomotion, difficulty swallowing, and difficulty with speech.

Exposure to welding fumes can cause disorders of the central nervous system and neurological problems. Typical symptoms include tremors or shakiness, decreased movement or rigid muscles, loss of balance, joint and muscle pain, slow movement, sterility in men, short term memory problems, slow or slurred speech, hand stiffness and pain, and other neurological symptoms.

Welding Lessons

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Welder News

Noonstar asked:

Course Programme (2-5 days):

Gas safety

Basic principles

Selection of nozzles

Gas pressures

Welding various joint types in position Oxy-Gas Welding

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Description of the Process

Oxy-Acetylene welding relies on the heat of a flame to melt the material being welded. Fusion can either be autogenous or with the addition of a filler material.

Safety

The high flame temperature required for oxy-fuel welding and cutting processes is obtained by combining oxygen with a fuel gas to produce flame temperatures of approximately 2500°C to 3000°C. There are certain precautions to be taken when using gases and these are described below:-

Fig.1 OXYGEN (black, right hand thread) should be handled carefully and must not be stored in warm areas. The pressure of oxygen in cylinders when full is 2500lbs.per square inch (200 bar) at normal temperature and any rise in surrounding temperature will cause an increase in cylinder pressure above 2500lbs.Oil or grease should never be allowed to come into contact with oxygen cylinders as an inflammable mixture will be formed, which may ignite spontaneously.

Fig. 2 ACETYLENE (maroon, left hand thread) should be stored in a separate fuel compound as acetylene and air form an explosive mixture, these cylinders should also be chained when either in use or in storage. No alloy containing more than 70% copper should be used on any part of the equipment as a highly explosive compound is formed. Cylinders must always be stored upright and away from high temperatures.

Fig 3. PROPANE (red, left hand thread). Storage as for acetylene, a fuel gas. Highly inflammable and can form explosive mixtures with air or oxygen (2% to 10%). With propane being heavier than air it can flow easily in still air some considerable distances therefore care must be exercised when using this gas.

Equipment

Pressure Regulators

Regulators should always be treated as delicate, precision instruments and must not be subject to sudden pressures or knocks. Not only are regulators identified by colour, they also have right hand or left hand threads depending on the type of gas being used. The type of thread can be identified by a notch cut on the equipment connections, showing the gas to be a fuel gas.

Single or multi stage regulators are available depending on working conditions. Single stage are suitable for welding with maximum outlet pressure of 2.1 bar, or scrap and heavy duty cutting with pressures of 8.3 to 14 bar.

Multi stage reduces pressure twice, giving a more stable output pressure, suitable for quality welding and cutting applications.

Blowpipes

Various types available, low pressure and high pressure, high pressure where gas is mixed in either the head or the shank, while a low pressure blowpipe with an injector mixing can be used with low pressure. Cutting torches must be kept clean and free from oil, grease etc. and periodically inspected for wear and damage.

Gas Hose

Should be maintained in good condition at all times and fitted with the proper connections. Most hoses are fitted with hose check valves to prevent damage to the regulators.

Flashback Arrestors

These are safety devices on the outlet of the oxygen and fuel gas regulators. A highly sensitive cut off mechanism operates at the slightest back pressure, whether the pressure wave is slow or sudden. An effective non-return valve, which also prevents flashback.

Oxy-Acetylene Welding Techniques

There are two techniques used to weld flat joints:

Leftward Welding

This method is used on low carbon steel sheet and plate in thicknesses up to 5 mm and also on cast iron and certain non-ferrous metals. As the name implies, the weld is started at the right hand side and progresses towards the left. The filler rod precedes the blowpipe and is held at an angle of 30° - 40° to the work surface. The blowpipe is held at an angle of 60° - 70° to the work surface and is given a slight side to side movement to ensure side fusion as the filler rod is fed into the molten pool.

Fig. 4

Rightward Welding

This method is used on steel plate over 5 mm thick. The weld is started at the left hand side of the joint and progresses towards the right. The blowpipe is held at an angle of 40° - 50° to the work surface and travels in a straight line. The filler rod, which is held at an angle of 30° - 40° to the work surface, follows the blowpipe and is fed into the molten pool with a circular action. A considerable amount of practice is required to perfect this technique.

The advantages of rightward welding over the leftward technique are higher speed, less distortion and more economical use of gas and filler rod. This is due to the fact that thicknesses up to and including 8 mm need not be bevelled and for butt joints in plate over 8 mm the included angle of the vee preparation is only 60°.

Fig. 5

The Oxy-Acetylene Flame

The heat source for this process is a chemical reaction resulting from the combustion of acetylene with oxygen. This is an exothermic reaction in which equal volumes of acetylene and oxygen supplied by the blowpipe react to produce carbon monoxide and hydrogen as products of the first stage of combustion. The reaction is as follows:-

Fig. 6 The Oxy-Acetylene flame

Theoretically, equal volumes of oxygen and acetylene are supplied to the blowpipe.

Chemical reactions are as follows:-

Stage 1

Acetylene + Oxygen = Carbon Monoxide + Hydrogen

C2H2 + O2 = 2CO + H2

Stage 2

Carbon Monoxide + Hydrogen + Oxygen = Carbon Dioxide + Water

CO + H2 + O2 = CO2 + H2O

In Stage 2, the carbon monoxide burns and forms carbon dioxide, while the hydrogen which is formed from the action in Stage 1, combines with oxygen to form water. The combustion is therefore complete and carbon dioxide and water (turned to steam) are the chief products of combustion.

This produces a flame temperature of approximately 32000°C.

Oxy-Acetylene Flame Types

Neutral Flame

As the supply of oxygen to the blowpipe is further increased, the flame contracts and the white cone becomes clearly defined, assuming a definite rounded shape. At this stage approximately equal quantities of acetylene and oxygen are being used and combustion is complete, all the carbon supplied by the acetylene is being consumed and the maximum heat given out. The flame is now neutral, and this type of flame is the one most extensively used by the welder, who should make himself thoroughly familiar with its appearance and characteristics.

Carburising Flame

This is a flame in which an excess of acetylene is burning, i.e. combustion is incomplete and unconsumed carbon is present. When lighting the blowpipe the acetylene is turned on first and ignited, giving a very smoky yellow flame of abnormal size, showing two cones of flame in addition to an outer envelope; this is an exaggerated form of the carburising flame, but gives out comparatively little heat and is of little use for welding. When the oxygen is turned on and the supply is gradually increased, the flame, though still of abnormal size contracts towards the blowpipe tip where an inner white cone of great luminosity commences to make its appearance. If the increase in the supply of oxygen is stopped before the cone becomes clearly defined and while it is still an inch or so long, the result is a carburising flame which is mainly used for hard surfacing and should not be employed for welding steel as unconsumed carbon may be introduced into the weld and produce a hard, brittle, deposit.

Oxidising Flame

A further increase in the oxygen supply will produce an oxidising flame in which there is more oxygen than is required for complete combustion. The inner cone will become shorter and sharper, the flame will turn a deeper purple colour and emit a characteristic slight “hiss”, while the molten metal will be less fluid and tranquil during welding and excessive sparking will occur. An oxidising flame is only used for special applications, and should never be used for welding.

Oxy-Fuel Gas Equipment Safety Test

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Copyright © 1997 Materials Engineering (UK) Ltd Tel/Fax: (+44) 01332 264452 or 263343

Welder Photos

Muna wa Wanjiru asked:


Like in all domains that require precision of execution, welding makes use of conventional standard signs that help to the better execution of a weld according to blueprints. The welding symbols systematized by the American Welding Society indicate the exact place where welds need to be made, the kind of joint necessary for it and the amount of filler to be used in the joint. Learning how to work with welding symbols is part of the training programs welders have to attend before receiving any certifications. What do welding symbols actually consist of? The main basic elements are the arrow, the reference line and the tail.

All welding symbols are built starting from the reference line, this is the very foundation of the sign as such on which you add other data necessary for the process. The connection between the reference line and the joint area is made by the arrow, but the direction of the arrow has no influence on the meaning of the reference line. Last but not least, the tail is not a compulsive element of all welding symbols, some have it, others don’t. It is generally used in case you want to add some information or supplementary specification to the process.

There are all sorts of peculiarities connected to the use of welding symbols. For instance, if any signs are included in the lower part of the reference line, you’ll have to make the weld on the side of the joint indicated by the tip of the arrow. In case the welding symbols are present on the upper side of the reference line, then the weld needs to be made on the side opposite to the direction pointed by the tip of the arrow. Both sides of the joint must be welded when you have signs included on both sides of the reference line. Deciphering such instructions from blueprints is essential for the proper working of the welding process.

Two kinds of welding symbols may appear on the reference line and they are essential when it comes to understanding how to make a specific weld. The most important sign here is a circle that means “welding all around”, thus, you will have to make the weld all around the joint in the direction indicated by the tip of the arrow. Sometimes it is not possible to weld around one single surface, and in such cases, the presence of the circle would be incorrect. Under such circumstances there should be other specificities related to the process.

Mig Welder

Muna wa Wanjiru asked:


The modern use of laser welding is rooted in the scientific discovery of the first laser in the 1960s, when the effects of an amplified light beam forced by radiation emission were put into practice. The working principle behind laser welding actually lies in the emission generated at the meeting point between light and metal, with the latter emitting force radiation. Presently, laser welding is expanding in various domains of activity since it brings enormous advantages with it such as a very deep weld penetration and minimal levels of heat inputs which cannot be achieved with traditional welding technologies.

The energy transfer is the one that makes the difference between classical welding and laser welding in various domains of activity. We can talk about two elements that characterize the efficiency of laser welding; first of all the heat ratio required by a specific workpiece and then the melting power in the fusion area. Furthermore, laser welding does not depend on AC or DC outputs and it is not limited by the conductive property of a specific material. The contact and fusion are possible with almost any material without even creating x-rays or requiring the formation of a vacuum.

The working principle in laser welding is the energy of light, hence the results are almost impeccable with a welded joint that has highly superior resistant properties. The penetration of a metal piece is directly influenced by its physical properties like conductivity, thickness or density; when a concentrated beam of energy is applied to a workpiece, the melting is immediate before heat may affect the operational area as such. The force of the energy beam in a focal point is given by the careful choice of special lenses. Correct mirror and lens applications in laser welding may guarantee the concentration of the light beam on spots smaller that 0.005.

The main industries to profit from the use of laser welding are aerospace building, military and defense, medical research, instrumentation, electronics and so on. Laser welding actually improved the execution of many delicate works that were almost impossible to achieve before, and here we refer to the creation of very deep or narrow welds and the absence of any distortions in the process. Small or very thin items could not be joint very well before the development of laser welding, not to mention that the resistance of the welds is incredible as compared to those resulted from classical welding procedures.

Welding Lessons

Wilf Staton asked:


Laser welding plastics is a fairly new process. It super heats the polymer without physical contact. Most applications processes are done by, directing the beam of infrared light. Directly at the weld joint. This is done by going through one of the parts. Commonly referred to as, through transmission.

By directing infrared beam of infrared light at the weld joint via( a laser)welding. This technique, the infrared beam, usually a laser, irradiates the joint through a part and the light is absorbed at the surface of the other. While broad band infrared beams can be used, the monochromatic lasers allow very fast heating of small areas of the part that allows the parts to be welded very rapidly, but with very small changes to the geometry part.

Laser welding is a example of electromagnetic plastic welding process. Once radiant energy it has been directed towards polymer surface, a series of three things will happen to it, most of the light transmits through, some is absorbed, and some is reflected away. The application the process involves directing the beam of infrared light towards the weld joint through one of the parts. The part (laser) that transmits most of the energy will not heat, but the absorbing part will super heat .Most virgin, organic polymers will not absorb energy. Certain dyes and fillers such as carbon black are used. To absorb the energy at the weld joint interface. This is commonly called to as through transmission infrared (or laser) welding. Welding results when materials are heated to a molten state and fused together.

One type of material must transmit the laser light while the other absorbs it, While converting it to heat. The great news is that the materials must be transmissive. This all depends on formulation of the pigment. Joints that require optical clarity can be done by the use of special coatings types. Thermoplastics, Laser welding, resin compatibility , resin chemistry or melt temperature differences than most all other plastic welding processes these days.

Nd:YAG laser welding is used commercially, a wide range of C-Mn steels, stainless steels, coated steels, molybdenum, titanium, and aluminum alloys. Low heat input welding. These lasers is utilized in the electronics, domestic items, automotive sectors, the most interest has been shown more recently, to particularly for the high power CW lasers in the shipping industry. Oil and gas, R&D issues involving development of highly powered lasers of better beam quality, the use of distributed energy in the beam focus, maintenance for both thick and thin sections and weld classification.

Light energy is generated by lasers. That can be absorbed into materials and converted to heat energy. Laser emits coherent radiation. Lasers do minimal divergence that can travel over significant distances without loss of beam quality or energy.

Relatively new techniques in Laser welding have been compared to other plastic welding processes. Dedicated laser labs at EWI’s are equipped with lasers creating and analyzing plastics welding. The laser beam used to melt the base material and filler rod, this process becomes line of sight ,as well as focal point limited process. If you cannot get a straight shot, or you can’t re-line the position of the weld area, it will not work efficiently or correctly. Microscopic magnification is also is used in the laser welding process.

The system is capable of welding materials that are galvannealed, electroplated or hot-dipped galvanized, that the coating thickness be both consistent on top of surface of the material, as well as controlled to 14 microns or less. The 3-kW diffusion-cooled slab laser used in the Utica system can be used to weld materials, ie mild steel, high-strength steel, stainless steel, aluminum. The biggest driving factor behind the development of laser welding is the fact that it makes the cans more esthetically attractive.

Beam delivery used optics that are mounted directly on the laser housing and fixed in focal length and beam position relative to the housing. Moveable part concept ,diode lasers mounted on robotics. Multiple-beam processing is new , relatively new field that has the potential. Enhancing the capabilities of high intensity laser and electron beam process.

Post heating, multiple-beam laser preheating is shown, first presented and analyzed. Followed by multiple-beam flow. this application electron beam welding. Other applications using laser machining and cladding. Particles with high melting points were distributed on the plate material in order to see the motions of these particles. And the enclosed motions of the melt pool during welding with different type of process gases. Photos show a change in the melt flow direction ,with active gas components towards the center of the pool and downwards towards the root side.

Welding Basics

Tom Sample asked:


Welding is much more than taking two joints and soldering them together. It’s a precise trade that requires proper training and education to perform safely and accurately. There’s nothing “simple” about welding and, in fact, it can be quite a dangerous undertaking. Considering this, welding safety, including proper gear such as welding helmets, is vital for getting the job done right.
The process of welding is especially dangerous for the eyes. This is so for several reasons, including the brightness of the arc, the ultraviolet and infrared rays it emits and the fact debris can sometimes fly loose. Inasmuch, no smart welder gets started without a good helmet.
Knowing you need a welding helmet and choosing one that’s appropriate for you can be two different things. The sophistication of the helmet needed will, of course, depend on the type of welding being done and how often you need it. If you just need to do a solder once in a while, a basic helmet will do. A pro, however, will likely want a more sophisticated piece of protection.
Here are some features to look for in a helmet:
* Comfort. A welding helmet should be comfortable to wear and lightweight. If it’s not comfortable, or reasonably so, it can get in the way of the job, which can lead to accidents.
* It should be easy to use. A helmet should not be so difficult to use that welders try to avoid them or go without them when making a solder.
* Visibility. Being able to see what you’re doing while working a weld is vitally important. The helmet should not block all fields of vision.
* Degree of protection. Welding shields must block ultraviolet rays to be considered effective. These are not sunglasses and the arc you’re dealing with won’t even begin to compare to a 100-watt light bulb! They should also block infrared wavelengths.
The type of helmet necessary will depend on the job being done and the kind of weld being made. Depending on the materials, lung protection might also be needed as some fumes created during the welding process are toxic. There are some other features welders can look for in a helmet to help them with more advanced jobs. They include:
* Auto-darkening helmets. These are great for shop situations where being able to see more clearly when the arc hasn’t been struck is important, but taking a helmet on and off isn’t always practical.
* Solar and battery powered helmets. These help control the auto darkening features on some helmets and some other processes as well. Either is suitable, as long as a solid helmet is chosen.
* Fixed and variable shades. The fixed offers a single darkness factor on the shade, the variable allows different settings to be chosen.
* Other features in helmets can include: adjustability to make it easier for a person who wears glasses to find a comfortable fit, sensor bars to assist in determining when a helmet’s features should be automatically turned on, curved shields and so on.
The key to welding and doing it safely is to not only understanding the process and the equipment, but to also have a good helmet. The helmet is vital for protecting the eyes and the face from harmful light rays, burning and flying debris.

Tig Welder

specialhag asked:


the hourly wage i am looking for is what is paid in edmonton AB for a journeyman welder /fitter

Tig Welding