File Name: welding problems and solutions .zip
- CAMM Metals Blog
- A Practical Guide to Welding Solutions by Robert W. Messler
- Arc Weld Troubleshooting
CAMM Metals Blog
TIG welding mistakes and solutions. The TIG process is complex, and it is undisputedly the most difficult process to learn. The weld here shows contamination caused by lack of shielding gas, which can happen when the shielding gas is not turned on, there is either too little or too much gas shielding, or the gas is blown away. As you can see, the weld did not break through the aluminum oxide layer. This created a weld where the filler metal mixed in with the partially melted oxide and created the contaminated bead seen here.
If you notice a brownish oxidation or flakes that look like black pepper in your weld puddle Figure 2C , increase the cleaning action. However, note that too much EP causes the tungsten to ball excessively Figure 2D and provides too much etching. This indicates that the oxide has been removed and it is safe to add filler and move forward. Adding filler to the weld zone before the oxide layer is adequately removed will result in contamination.
Figure 2B shows the way an aluminum TIG bead should look. Figure 3 shows a bead with a grainy appearance, which is typically caused by filler metal problems. For instance, a aluminum filler rod from one manufacturer may have different properties than a rod from another manufacturer.
The welder if the application permits may need to adjust filler brand accordingly. The rod may also be defective too much of a certain ingredient. The welder may even have the wrong type of filler rod, such as filler instead of filler. Prior to welding, always check the filler metal type and remove all grease, oil and moisture from the surface to prevent contamination. Lack of fusion at the root of a T-joint or a fillet weld can be caused by a number of factors: improper fit-up, holding the torch too far away from the joint increasing arc length and improperly feeding the filler rod, to name a few.
This issue may be seen more often with a transformer-based machine, as the arc tends to wander between the two sides of the joint as it seeks the path of least resistance. In this case, reducing arc length will provide better directional control and help increase penetration. It is also important not to under-fill the joint or weld too quickly. Note that inverter-based machines especially those with advanced output controls such as adjustable frequency and pulsing controls offer more control over the arc.
These controls create a narrower, more focused arc cone that provides better directional control over the weld puddle and deeper penetration and often at increased travel speeds.
Craters, such as the one shown in Figure 5A, typically occur at the end of the weld, and they often lead to cracking.
Causes include instantly reducing the welding power which causes the puddle to cool too quickly and removing the filler rod too quickly at the end of the weld. You can easily fix crater cracking issues by continuing to feed filler rod while slowly reducing current at the end of a weld. Note that some TIG welders feature a crater control function that automatically reduces the current at the end of a weld.
The result is a good-looking weld bead, as seen in Figure 5B. One of the first things you should have learned about welding is to clean materials prior to welding.
All base and filler metals need to be cleaned, whether the contaminant is mill scale, oxide on aluminum or dirt and grease on filler metals. Grind, brush and wipe away all potential contaminants. For cleaning aluminum, dedicate a stainless steel brush to the task to prevent contamination from other metals. Figure 6B shows what happens when a weld on mild steel has been properly cleaned before welding.
Figure 6C shows a weld made on chrome-moly tubing that has not been cleaned, while Figure 6D shows a weld made that has been cleaned prior to welding. Unfortunately, once this error is made, there is nothing that can be done to fix it except for scrapping the part and starting over. To prevent overheating, reduce amperage, slightly increase travel speed or shorten the arc length. If your welding equipment features pulsed welding capabilities, now is the time to learn how to use them.
Pulsing reduces heat input, and it offers excellent control of the weld puddle. Figure 7B shows proper coloration of stainless. Figure 8 shows sugaring on the backside of a stainless steel weld. Sugaring oxidation occurs around the weld when it is exposed to oxygen in the air. The best way to prevent sugaring is to back purge the weld with argon shielding gas or reduce welding amperage.
Figure 9A shows what a weld bead looks like on aluminum with the amperage set too high. This creates a wider profile, an ill-defined bead and can potentially lead to burn-through.
Reference back to Figure 2B to identify an ideal weld. The color change in the middle of this aluminum weld bead Figure 10 resulted from an increase in arc length. Arc length, which is the distance between the electrode and the base metal, determines TIG welding voltage. Holding too long of an arc increases overall heat input and the potential for distortion, widens the weld bead while decreasing penetration, and affects weld bead appearance. Practice holding a consistent arc length to improve heat input control and improve weld bead quality.
This article originally appeared in The Fabricator Magazine and is shared with permission. To activate your FREE subscription today, simply select which newsletter s you would like to receive and complete the form below.
Or if you don't have a Miller account, create one today. Thank you for subscribing to our eNewsletters. You can manage your subscription s by signing into your account. Learn about common mistakes when TIG welding as well as basic tips on how to prevent these errors.
Poor gas coverage leads to contamination The weld here shows contamination caused by lack of shielding gas, which can happen when the shielding gas is not turned on, there is either too little or too much gas shielding, or the gas is blown away. Set the proper gas flow rate, which should be 15 to 20 cubic feet per hour cfh. In fact, excessive gas flow creates turbulence and swirling currents that pull in unwanted airborne contaminants and it can cause arc wandering.
Generally, err on the lower side of recommended shielding gas rates to ensure proper shielding coverage without turbulence. Check all the fittings and hoses for leaks. Rub soapy water over the hose and all fittings. If bubbles form, you have a leak and need to replace the defective components. Assuming you have a full cylinder, the right type of gas and no leaks, consider that you may have a tank contaminated with moisture.
Shielding gas cylinder contamination does not happen frequently, but it is possible. Check with your gas supplier to resolve this issue. Figure 1: Poor gas coverage leads to contamination 2. Figure 3: Grainy aluminum weld 4. Lack of fusion in the root Lack of fusion at the root of a T-joint or a fillet weld can be caused by a number of factors: improper fit-up, holding the torch too far away from the joint increasing arc length and improperly feeding the filler rod, to name a few.
Figure 4: Lack of fusion in the root 5. Craters Craters, such as the one shown in Figure 5A, typically occur at the end of the weld, and they often lead to cracking. Sugaring on stainless steel Figure 8 shows sugaring on the backside of a stainless steel weld.
Figure 8: Sugaring on stainless steel 9. Too much amperage on aluminum Figure 9A shows what a weld bead looks like on aluminum with the amperage set too high. Proper arc length control The color change in the middle of this aluminum weld bead Figure 10 resulted from an increase in arc length. Figure Change in arc length This article originally appeared in The Fabricator Magazine and is shared with permission. Related Products.
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A Practical Guide to Welding Solutions by Robert W. Messler
Calibrated expressions for welding and their application to isotherm width in a thick plate. The present paper introduces a possible solution to the limitations of modern trial and error solutions to welding procedure development. Dominant factors are identified, with effects from secondary phenomena being taken into account by correction factors. These correction factors are then calibrated and presented in a form that can be easily computed, and therefore be amendable to industry. Recent advances in technology have made it possible to consider welding a scientific endeavour rather than an art form . These advancements mean that welders can now make use of plasma arcs, lasers, electron beams, explosives, and mechanical devices to join metals at the atomic level .
Arc Weld Troubleshooting
Disclaimer: welderportal. When you purchase through links on our site, we may earn a small commission at no extra cost to you. GMAW is considered one of the easiest welding processes to perform. However, even working with this simple tool can have its own complications.
TIG welding mistakes and solutions. The TIG process is complex, and it is undisputedly the most difficult process to learn. The weld here shows contamination caused by lack of shielding gas, which can happen when the shielding gas is not turned on, there is either too little or too much gas shielding, or the gas is blown away.
Over the years, these welding techniques have been simplified with superior welding equipment. With such equipment, it is possible for many operators to forget essential steps when performing the weld. However, when these same operators run into trouble, they are unable to diagnose and correct problems. Here are some common welding issues and how to correct them. In gas metal arc welding GMAW a common unwanted side effect is the creation of what welders call spatter.
Welding is an important part of the metal fabrication process. However, there are many different issues that can arise from welding.
Use this matrix as a quick reference to link common welding issues with standard causes Interactive and printable PDF. Missing welds may be the result of operator placement mistakes, or the result of machine errors in performance or settings. Undersized welds can be the product of dirty or damaged parts and materials, or of incorrect welding setups. High weld current, high weld force and long squeeze and hold times may cause deep indentations that do not meet specifications.
Hello, this is Amrit here, in today's article I will talk about the Welding Defects. As we already know welding is a vast topic, there are countless books are written on welding, so imagine how important the topic is! Don't worry I classified welding defects into some basic parts, and it is enough for your diploma or any undergraduate studies.
Messler, Jr. PDF Free Download. A convincing argument can be made that joining by mechanical fastening or design feature interlocking, adhesive bonding, or welding, including brazing and soldering, is the most important process in manufacturing and most construction because it usually occurs after a considerable value has already been added to produce the near-net-shaped detail parts for assembly. As welding is typically the most technically elaborate, requiring the most skilled practitioners, and accounts for about half of all join, it almost certainly accounts for much more than half of all joining by value.
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