Welder World Blog

Archive for December, 2009

Storage and Handling

After finishing gas welding, Always keep gas and oxygen cylinders with minimum of 20 feet distance between them. Or, divide them with a right firewall. As the cylinders can caught fire easily, keep the flammable and combustible materials away from cylinders. Store cylinders away from physical injure, heat, and tampering. Always maintain cylinders in an upright position. If possible, Chain them steadily to keep them from falling over. Ensure that the cylinder valves has been closed or not before moving. Defending caps or regulators should be kept in place. Roll cylinders on bottom edges to move it from one place to another place. Do not pull it. Try to reduce cylinder movement as much as possible, while transporting it.

General Gas Welding Safety Tips

To lift up gas cylinders, use the equipments that are designed for lifting it. Do not use any other tools for lifting it. Check torches and clean only with the suitable tools. Blow-back protection torches must be used while welding. Always keep an eye on the equipments and ensure any leakages at all connections. This can be done by using an approved leak-test solution. Inspect hoses for leaks and worn places. Replace bad hoses at regular intervals. Keep fire extinguishers easily reachable places, at the welding site. Keep away hoses and cylinders from sparks, flames, and hot metal as the sparks create holes on it. To fire the flame in welder, always use a flint lighter. Stand to the side when opening cylinder valves. Use two-stage regulators whenever feasible. When using a single-stage regulator, open cylinder valves very slowly. This keeps rapid high pressures from exploding the regulators. When using a single-stage regulator, only open the acetylene cylinder valve 1/4 to 3/4 turn. Leave the wrench in place. By doing so, you can close the cylinder quickly in case of any emergency. Open and light acetylene first. Then open and adjust oxygen to a neutral flame. When shutting off the torch, first you have to close the acetylene torch valve You might hear a pop as the oxygen blows out the flame, but the flame will not burn up the acetylene line. When you done: Close cylinder valves. Bleed the lines to take pressure off regulators. Carefully coil hoses. Restore equipment.

Welding gases and fumes may be hazardous to your health. All welding processes produce hazardous gases. Gases are invisible to the eye and does not contain odor. Ultraviolet rays from the arc produce gases such as carbon monoxide, carbon dioxide, oxides of nitrogen and ozone. Fumes are also produced while welding. Welding “smoke” is an example of a visible fume.

Symptoms of harmful exposure produced during welding are as follows: You may have irritation in your eyes, nose and respiratory system, skin. Some other symptoms may be cough, chest pain, headaches, nausea, vomiting and fatigue. If you have these problems, consult a doctor and explain what you do for a living.

Welding gases and fumes do not cause immediate health problems. But as you keep working for various years as a welder and find out that breathe in gases and fumes in quantities is greater than OELs (Occupational Exposure Limits) your health will be affected. Quantity of gases and fumes caused by welding depends upon welding processes and other variables like current, voltage, type of electrode, polarity and type of shielding gas.

You can reduce exposure to welding fumes and gases by wearing respiratory protection, by implementing work rest schedules and safe-work practices, by introducing engineering controls and improving ventilation and substituting less hazardous flux materials.

To protect yourself from these gases and fumes you should take certain steps. Effective exposure is the first step to controlling exposure. Before starting to work, find out whether the fan is in working condition and filters are clean. Find out what materials and hazards you are dealing with. Before starting your work, make sure you read the Material Safety Data Sheet (MSDS) supplied with welding electrodes.

Use respiratory equipment because it is very important. Greater risk is involved while welding plasma arc and arc gouging. They are also high while welding stainless steel, alloy steel as well as galvanized, coated and painted steels. Always use respiratory equipment under such conditions. According to law, respiratory protective equipment must be of an approved type; suitable for hazard; must be selected and fit tested according to CSA standard and employer is responsible for providing appropriate equipment.

Examples of numerous other hazards present during welding are eye hazards, burns, electric shock, fire and explosion, compressed gas cylinders, heat stress, dust hazards, overhead, excessive noise levels and confined spaces.

A welder can get problem in his eyes due to ultraviolet rays, flashes, spatter, chipping or grinding. Burns can happen due to radiation, hot metal spatter or handling hot tools and equipment. Welding operator can get electric shock if cables are damaged, lack of proper gloves and working in wet conditions.

Hazards due to compressed gas cylinders can happen if there’s damage to cylinder valves and flashback.

Plastic welding and spot welding – both are almost similar to each other. There is a difference noted. In plastic welding, heat is supplied through convection of the pincher tips, instead of conduction. The two plastic pieces are brought together. At the time of welding, a jet of hot air is liberated. This melts the parts to be joined along with the plastic filler rod. As the rod starts melting, it is forced into the joint and causes the fusion of the parts.

Plastic identification is the first point to be noted in order to choose a suitable plastic welding rod. A plastic welding rod or thermoplastic welding rod is of a constant cross-section shape. Using this, two plastic pieces can be joined. It may have a circular or triangular cross-section. Porosity of the plastic welding rod is an important factor. Air bubbles in the rod will be created due to its high porosity. This is responsible for decreasing the quality of the welding. So, the rods used must maintain zero porosity. Otherwise, they should be void less. Products like chemical tanks, water tanks, heat exchangers and plumbing fittings are manufactured by using the technique of plastic welding. By adopting this technique, money can be saved.

Using plastic welding, two plastics can be welded together. This type of weld is performed on children’s toys, lawn furniture, auto parts and other plastic equipments which are used daily – both for domestic and commercial purposes. In order to join the thermoplastics, when they are heated an under a particular pressure, this type of welding is employed. In normal practice, using filler material, the pieces are joined together. There are certain occasions wherein filler material can be avoided. Generally, plastic is not durable and has a shorter life span. Natural elements like cold weather, ultraviolet radiation from the sun or continuous exposure to chemicals causing contamination, will create damage to plastic products. Plastic can be subjected to damage if it is hit on a hard surface. But, as the price of new parts is high, it is preferred to repair the existing products.

As there are different types of plastics, we must know which one we are working with in order to find the exact welding material to be used. We must know the difference between thermoplastics and thermo sets because it is not possible to weld thermo sets. If you use the wrong welding rod for the plastic to be repaired, bonding will not take place. As materials like polyolefin’s have a lower surface energy, a special group of polyolefin adhesives has to be used. When you are repairing plastic, there are usually two types of defects – a crack or a broken part. In the case of a crack, there is a particular stress affecting the inside of the material. You have to repair the crack and you should not continue through the piece.

There are many types of plastic welding.

Hot gas welding uses a welding gun which has electric heating elements. They produce heat f hot gas. Hot plastic welding uses a hot plate place between the two surfaces which are to be joined. In order to weld two pieces, ultrasonic welding uses a high frequency acoustic vibration. After subjecting them to high pressure, they are exposed to the vibrations until the weld is completed. Spin welding, where friction is employed to weld two cylindrical parts. These parts are rotated. The rotation stops at a particular point and the weld is completed. Vibration welding exposes the pieces to a frequency called amplitude. The two pieces are subjected to pressure due to which a friction is created which generates heat.

Arc welding has given us a significant large major step up in the construction of metal parts. So, how precisely does it work?

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The arc creates enough sustained high heat to melt the metal at the point of the arc allowing the metals to fuse. Electrodes come in 2 differing kinds. They are either consumable or non-consumable depending on if the electrode is really used up in the welding process or is able to be reused. These are just a few facts about arc welding.
The welding area is typically guarded by some form of inert gas. This is known as shielding. In the early days of arc welding, the shielding gases were oxygen and nitrogen. They tended to be crisp and porous and tended to fail. In the middle of the last century, research proved that hydrogen worked far better.

The welding industry is extraordinarily fond of the employment of initials in describing the various welding processes. MIG and TIG welding is a fine example. MIG welding means metal inactive gas welding and TIG welding is tungsten inert gas welding. Other common expressions are SAW for submerged arc welding and FCAW for flux-cored arc welding. The truth is that welding, although a particularly highly skilled craft, isn’t that hard to master. This is an important fact about arc welding because there is a dreadful deficit of qualified welders and the demand is growing every day. It was recently reported that the average age of the pro welder was a particularly high 54 years. It is easy to see that this rather old work force will be reaching retirement age in high numbers over the following a decade. This has led straight to the arc welding field being called one of the finest kept systems in the future work picture.
Due to the use of high voltage electric currents and unusually high temperatures, arc welding has traditionally been viewed as rather dangerous occupation. The risk from burns and electric shock was high in the past and the reputation was rather deserved. In fact, welding is now thought to be no more dangerous than crafts such as carpentry and plumbing.

Come visit us right here for more Welder and Welding Info and get two Welding Ebooks Sub Arc Welding. http://www.welderworld.com/
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Professional welding actually involves expertise & experience. A fairly extensive-knowledge is required to become an expert. Many years of exposure & skill are necessary to master the art of welding. After understanding the basics, one can learn more complicated skills.

First and foremost, one has to take safety precautions. Otherwise, unforeseen circumstances may even prove to be fatal. Damage to the eyes is a possibility due to intense light beams that emerge from the course of action. As electricity is involved in certain cases of welding, death by electrocution is a possibility. Before starting welding, helmet has to be worn for protecting eyes, hair, head & face. Wearing protective gloves & clothing is a must.

Arc Welding:

Arc welding is the most common technique used. It is the first lesson for welding. Instead of using a gas torch, high voltage electricity is to be used. In arc welding, a spark/arc is able to melt a metal & form a weld. This process is accepted by many as it is more accurate & produces a cleaner & stronger weld. In the category of arc welding, seven different methods are there to choose from.

Shielded metal arc welding may be the most suitable if you have large welds or metal welding in not-so-normal angles & positions. In this method, the electricity passes through an electrode using which metals can be melted. MIG welding (Metal Inert Gas welding) will be useful in a welding project which requires more speed. In this method, rods need not be used. In its place, equipment has to be used that passes current through a metal tip that does not melt. A separate piece of continuous wire is to be fed to the tip which forms the weld. Tungsten inert gas welding is slightly similar to MIG welding. It is applicable in thin materials where high quality weld is required & where speed is not necessary. There are other methods also – namely Flux-Cored arc welding (FCAW), submerged arc welding (SAW), plasma welding etc.

Aluminum Welding:

Aluminum is the most difficult alloy. Initially, aluminum oxide should be cleaned from the surface. Heat treatable aluminum alloys receive their strength from a process called ageing. Notable decrease in tensile strength will happen when welding aluminum due to over-ageing. For all other information on aluminum welding processes, please visit the homepage or any of the links connected to this.

Aluminum alloys can be divided into 9 groups.

Designation Major Alloying Element

1xxx unalloyed (pure) >99% Al
2xxx Copper is the principle alloying element.
3xxx Manganese is the principle alloying element.
4xxx Silicon is the principle alloying element.
5xxx Magnesium is the principle alloying element.
6xxx Magnesium & Silicon are principle alloying elements.
7xxx Zinc is the principle alloying element.
8xxx other elements (including Tin, some Lithium compositions)
9xxx reserved for future use

Aluminum alloys are readily available in the market. We can get them in various product forms. The following are the factors affecting aluminum welding.

* Aluminum Oxide coating.
* Thermal Conductivity.
* Thermal Expansion Coefficient.
* Melting characteristics.

Other welding Methods:

There are some other methods – resistance welding, energy beam welding & solid state welding. All these methods are useful in industrial applications where large scale & specialized requirements are involved.

What we have dealt with so far are only basic concepts. These are the fist lessons or fundamental steps from which on can go further to acquire more knowledge about welding procedures. One has to remember only a couple of basic methods. One has to practice a lot before arriving at a standard of excellence. Certain processes will bring easy results & some may not. Sooner or later, one will reach a stage & style which will be most comfortable for future operations.

Mig welding is just another name for Wire feeder welding. The fundamental idea behind wire feed welding is that you use a welding wire that constantly feeds through a MIG welding gun when you grip the trigger.

This is a nonstop welding process. You keep your finger on the trigger and the base metal, welding wire touching you can do wire feed weld all day. There are many different types of welding wire. You can use for many different welding applications.

Welding wire is the most commonly used for more than likely an AWS ER70S-6 classification wire. This welding wire is used fabrication shops and all welding for many different types of welds.

A cover wound wind of wire will be evenly wound onto the spool from left to right with each and every layer of wire in order to sitting next to the other. This type of process a lot better for wire feedability as there will be no bends and little kinks in the wire feed.

Random wound will be exactly random wound wire in any old type of fashioned.Because the wire is wound on the spool with each and every layer in a random fashion, the wire will cross over itself a a small amount of times. The spool starts to fill up with the wire feed, each and every time there is a intersect of the wires it can make a little bend in the wire.

These little bends in the wire can damage your wire feedability which in turn will affect your overall weld quality and feed.

When you are using a MIG welding machine or a wire feed welding machine you have welding consumables that need replacing on a regular basis. Every MIG welding machine gun will have a shroud and contact tip or a nozzle. And then depending on which type of brand welding torch you have there will also be a gas diffuser or some kind of insulator.

I guess that most home welders or DIY will use what is meant by gasless welding wire. This process is also known as a flux cored wire. Be careful though because there are two different types of flux cored welding wires. There are a lot more than two, but for general home welding wire feed make sure that you get a gasless MIG welding wire feed that is an E71T-GS.

Now if you want to do decide to use a gasless MIG welding wire you are going to have to modify the wire feed rolls. The reason for this mig welding wire is because it is a flux cored wire the wire is not solid all that way through. The flux is on the in the interior of the wire the wire is very soft.

So if the wire diameter is for dispute sake 0.9 mm you need to use a 1.0 mm get in touch with tip. This will really help with the smooth feeding of the wire and allow better welding.

Finally you’re going to have to use a a little larger get in touch with tip for when you use a flux cored wire.

Welding is a process using heat or pressure to join together materials such as metal or plastic.  This is a common way to join metals, and is used in the production of many goods, including automobiles, ships, trains, buildings, and bridges.  Though similar to the acts of soldering and brazing, welding is distinguished from these other methods in that a weld melts the metals together, while soldering introduces a softer substance that is melted and then used to hold the original pieces together without actually melting them.

Welding has developed greatly since its conception thousands of years ago.  Thanks to modern technologies, welders work with much greater precision and weld stronger welds than in the pre-19th century, when forge welding was the only technology and metals were welded by blacksmiths beating them together over hot coals.  The first World War created a surge forward in welding technologies, as the many countries looked into better and more efficient ways of welding ships and planes for the war.  As welding technology has increased, welding as become more robust and can now be performed by hand or automated by machines and even robots.  Welding can be performed in a variety of environments, including under water, and welding equipment can be very portable.  Despite these advances, welding remains dangerous, with risk to the welder of burns, exposure to poisonous gases and eye damage.

Today some of the more common methods of welding include gas welding, arc welding, resistance welding, spot welding, electron beam welding, laser welding, and robot welding.

Gas welding, properly called “oxy-fuel welding,” and commonly referred to as “oxyacetylene welding,” is a process in which gas an oxygen are mixed to produce a high enough temperature at the torch to melt the edges of the metal being worked with.  Thus oxy-fuel welding typically requires two tanks, one of oxygen, and another for the fuel being used.  This is one of the oldest techniques for welding, and is still commonly used, in part because the equipment is easily portable.  It is no longer commonly used in industrial welding, but is still often used for basic welds such as welding pipes together.

Arc welding is performed by creating an arc of electrical current between an electrode and the material being welded so as to attach the materials by melting them together.  Arc welding is commonly used in industrial applications because of its low cost.  A common problem with arc welds is that the oxygen and nitrogen in the atmosphere can cause welds to be brittle and weak.  This is overcome by introducing shielding gasses such as hydrogen, argon, and helium.

Resistance welding uses physical pressure combined with heat produced by the resistance of electrical current passing through the materials being welded. Resistance welding melts just enough of the materials to join them together when they are put under physical pressure. This method is popular because it is easily automated and economical at a high rate of production, though initial equipment cost can make this method cost prohibitive at lower production rates.

Spot welding is a specialized form of resistance welding (see above) used to join up to four sheets of metal together.  In spot welding two electrodes are used to clamp metal sheets, applying pressure and passing current through them.  This method is easily automated and energy effiecient, making it popular for industrial applications, particularly in automotive assembly.

Electron beam welding bombards the materials being welded with a beam of high velocity electrons, the impact of which produces heat, melting the materials and welding them together.  The electrons are produced by heating a hot cathode emitter made of tungsten.  This method is very precise, and used in the production of aerospace and semiconductor parts.

Laser beam welding makes use of a laser to join multiple pieces of metal together via its concentrated heat source.  This method is both precise and powerful, with little heat escaping the specific welding zone, and the laser able to send heat deep into the metals welded.  Laser beam welding is commonly automated and used in industrial applications such as automotive assembly.

Robot welding does not employ a different welding technique, but is distinct because of its level of automation.  Robot welding is the latest technology in welding automation, and is able to perform all steps in welding, including the preparation and handling of materials.  This is what sets robot welding apart from automated welding, in which a human operator is still required to prepare materials and run the automated machines.  Robot welding is used in high volume production operations, such as automobile assembly.

Multi-chamber IV bag has two categories: fluid multi-chamber IV bag and fluid-powder multi-chamber IV bag. It’s defined as the separate storage of different medicine in different sub-chambers by welding during production, storage and transportation. In application, the separate sub-chambers are connected by external forces, and the contents are mixed. Multi-chamber IV bag is mainly used for the contents that are unstable after mixing, and can not guarantee long term storage. This article analyzes the testing of two key factors for multi-chamber IV bags: welding and barrier property. 

1.The Analysis and Testing of Welding Strength

For the welding strength of multi-chamber IV bag, its convenience, safety and protection for isolated contents during storage and transportation must be maintained. Therefore, multi-chamber welding process control is the key procedure in the whole production. Welding is determined by three indexes: temperature, time and pressure. Multi-chamber IV bags, to achieve safe storage and transportation as well as easy clinical operation, can only maintain a mediate welding strength, which is also called heat seal strength. How to control this index successfully is a focus for multi-chamber IV bag manufacturers.

Labthink HST-H3 Heat Seal Tester and XLW (PC) Auto Tensile Tester are the professional testers for multi-chamber IV bag and its indexes. When testing the finished multi-chamber IV bags, a specimen of the welding place is prepared. This specimen can be automatically tested after clamping and pressing the ‘heat seal’ button on XLW (PC). Besides, for the proper welding strength, the manufacturer needs to make researches on temperature, time and pressure. HST-H3 Heat Seal Tester can be applied with the auto tensile tester for the best heat seal temperature, time and pressure indexes.

2.The Analysis and Testing of Barrier

Barrier property is the most important factor affecting the quality of fluid and fluid-powder multi-chamber IV bags. Owing to the low barrier property of the content contact package, a barrier package is needed for prevention of oxygen and moisture permeation. Besides, nitrogen is applied to take place of the air between the inner package and barrier package. Therefore, oxygen transmission as well as nitrogen and moisture transmission should be tested. Labthink VAC-V series of differential pressure gas permeation testers can accomplish relevant testing.

The application of multi-chamber IV bags is the great development of IV bags. As the most strictly required package for medicine, its tensile strength, elongation, heat seal strength, puncture performance of film and closure and seal property all need to be tested. Labthink, as the excellent provider of testing instruments and services, has been providing most excellent and thorough quality control solutions for the global medical industry. Labthink is willing to have more communication and cooperation will pharmaceutical companies and institutions. 

Labthink Instruments Co., Ltd.      

No. 144 Wuyingshan Road, Jinan 250031, China

Tracy Bao  info@labthink.cn

Tel: 0086 531 85061153  fax:0086 531 85812140

In welding jargon stick welding is a nickname for Shielded Metal Arc Welding (SMAW) or Arc Welding. The name stick welding is the result of the stick like appearance of the electrode that forms the crust of arc welding. There are 5 most basic aspects that can be very influential in deciding the effectiveness of the process. They are what we call as CLAMS.

CLAMS should be expanded as
C – Current setting
L – Length of arc
A – Angle of travel
M – Manipulation
S – Speed of travel

Current setting – Electrode and its type influences the decision of selecting the appropriate current of amperage. Operating ranges can be read from the display at the side of the electrode box. The newest machines do bear with them a label that suggests you appropriate amperage values for the list of electrode thicknesses that are most often use.

Length of arc – Longer lengths lead to excess spatter and undercuts too. Choose a length that is most appropriate to the electrode that you have decided to use for the specific task. Avoid holding the electrode way too close as it leads to a sharp decrease in voltage. Newbie make a mistake of holding the electrode too far and produce a lot of spatter. Constant practice will teach you that controlled and tight length of arc will result in minimal spatter and great beads.

Angle of travel – Perpendicular position will lead to great beads.

Manipulation – It is wise to build up on the basics that you have acquired. But the basics should be strong as this is what can take you places as a professional welder. With keen observance and innovation at your leisure will eventually give you your own style of performing the job.

Speed of travel – Continually maintaining the same speed of travel will give you good beads. However you have got to alter the speed to make the arc stay within the specific area. High speeds will produce high crowns and undercuts too. They are not efficient when it comes to penetration too.

Most important of these all, be open and prepared to accept your mistakes. No one person has mastered the art without any errors whatsoever. But try to keep your view strictly to the puddle. Make necessary arrangements so that you get a clear view of the puddle. Be calm and learn from your mistakes. That is the best that you can do as the first step towards learning. Also learn to re-weld you mistakes away. They are useful to keep wastage to a minimum. Keep yourself away from the harm that a machine is capable of and strictly adhere to the safety precautions that should be followed while performing these risky tasks.

I need to design a welding table for shops class but i don’t know how hot the table gets when its being welded on. Also will a part of the table that’s not close to the area that’s being welded on, will it get hot? Like the legs or something.