The Xiris Blog

What Does Welding Sound Like? GTAW

Posted by Cameron Serles on Tuesday, October 29, 2019 @ 11:30 AM

To accompany the launch of Xiris’ new audio monitoring technology, we are continuing our series about sound in welding. So far, we have covered the announcement of our audio monitoring equipment, benefits of adding audio to your weld camera, and sound in GMAW

Today we are investigating sound in GTAW, or TIG welding.
GTAWGTAW is typically characterized by a high-pitched hum or buzz.1

The polarity of the electrical current—whether it’s AC or DC—affects sound in TIG. AC TIG is much louder than DC. As amperage increases, welding noise will also increase.2

At lower frequencies, you will hear a slow pulse sound as you weld. One operator described it as “Braaap, Braaap, Braaap.” As the power frequency increases, such as to 80-90 hz, the sound becomes “sharper:” “BRAP, BRAP.” With the frequency between 100-120 hz, the “brap” sound becomes a whine. At this point, the arc is moving much more quickly, going from positive to negative hundreds of times a second.2

As in GMAW, sound in GTAW can alert operators to mistakes or faults in their welding.

For example, a torch-to-workpiece angle greater than 20-25 degrees may cause a popping sound as well as poor weld quality.3 A high pitched buzzing sound can signify lower penetration of the heat into the parent material.4

An important consideration in monitoring sound in welding is the environment that you’re working in. Each shop or factory has its own unique acoustics. Some frequencies may echo and welding machines can seem very loud or sound different depending on where they’re located.

For this reason, it is important to spend time assessing your welds, monitoring your equipment and learning what a good weld sounds like in your facility.

Watch a video of welding aluminum with GTAW, and how the frequency settings change the sound: https://www.youtube.com/watch?v=XzsfBV6_vNY

 

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Sources: 

1https://weldtalk.hobartwelders.com/forum/weld-talk-topic-archive/welding-processes/12469-a-few-questions-on-tig

2https://weldingweb.com/showthread.php?23153-AC-TIG-Aluminum-Noise

3https://forum.millerwelds.com/forum/welding-discussions/3973-sound-of-tig-welding

4https://www.youtube.com/watch?v=XzsfBV6_vNY

 

Topics: quality control, weld camera, welding, GTAW, weld monitoring, audio

Using a Weld Camera to Accelerate On-The-Job Training

Posted by Cameron Serles on Monday, March 23, 2015 @ 03:46 PM

Fabricators who make large pressure vessels capable of holding 3000 psi (200 bar) or higher need to implement special welding techniques to ensure weld quality does not compromise the integrity of their vessel.

Often the pressure vessel is sealed at the time of welding so certain welding processes can only be done from the outside and require full penetration of the wall thickness. As a result, fabricators often choose not to use GMAW (MIG) welding processes to avoid the potential of burning through the wall and compromising the integrity of the pressure vessel wall.

Instead, GTAW (TIG) welding processes are used with the focus on manual TIG welding because of the complexity and uniqueness of the welds required. This requirement for manual TIG creates a problem in training operators to such a high level of skill that they are able to achieve the level of quality required.

One fabricator found out that during training of new welder recruits, they had no way to correct the new welder`s techniques as the welding was happening: they could only identify flaws in the weld after the fact. A completed weld would be inspected and suggestions given to the trainee as to how improvements could be made; this process would then be repeated many times. The fabricator needed a more effective way to train a new recruit.

The fabricator chose to implement a Xiris XVC weld camera. The Xiris XVC weld camera can acquire images with a wide dynamic range so that a huge range of brightness can be seen in a single image: the very intense brightness of a welding arc AND its darker background can be seen by the camera in a single image. By implementing a weld camera right at the weld location, the new welding recruits could learn immediately when a defect in the weld process had occurred and adjust their technique accordingly. Additionally, the video recording feature of the weld camera allows recruits to replay the video of a welding pass for maximum learning opportunity.

 

March23_TIG_HandWelding_Final

 

Conclusion

By implementing a camera for training purposes, fabricators can eliminate the trial and error process of teaching new recruits critical real time welding skills. By pre-recording an example of a good weld, new recruits can be taught good welding techniques. By recording actual weld segments made by a new recruit, process feedback can be given and explained using the recorded weld segment. As a result, weld training time and materials can be reduced and process accuracy can be improved.

 

 

Topics: GTAW

Using a Weld Camera to Monitor Narrow Groove Welding

Posted by Cameron Serles on Thursday, October 17, 2013 @ 12:44 PM

In the past few years, Narrow Groove Gas Tungsten Arc Welding (GTAW/TIG) has evolved to become the most-productive pipe welding technique for the construction and repair of power plants. The technique is also being increasingly used in the assembly and repair of turbomachinery.

Remote weld monitoring of Narrow Groove Welding is necessary to achieve maximum weld process quality control.However, to have success with Narrow Groove Welding, monitoring with Weld Cameras is usually necessary.  

Narrow Groove Welding and Thick-Walled Pipe

In both new and legacy power plants, pipes with thicker walls and greater pressure-resistance have become necessary because of considerably increased operating-temperature requirements. The pipes must be made from high-temperature steels with high creep rupture strength as a key quality feature—and the welds of these pipes have to follow the same parameters.

Some of these new pipes have wall thicknesses that approach , requiring more-efficient and affordable welding techniques, without compromising quality. Narrow Groove Welding best meets this need.

Narrow Groove Welding is usually used on wall thicknesses of at least and groove gaps greater than about or so. The sidewall bevel in the groove ranges from 0°-5°—compared to the 37.5° sidewalls in traditional weld preps. Into this narrow groove is placed a weld head (or two) configured as a thin plate of about maximum width, with integrated wire feeders. A side-to-side oscillation is used during the welding process to achieve consistent sidewall fusion.

Compared to welding with conventional grooves, Narrow Groove Welding provides numerous benefits to fabricators, including:

  • Reduced weld volume (at least 70% less than conventional grooves).
  • Reduced groove preparation time due to the smaller groove.
  • Reduced arc-on time with smaller joint.
  • Reduced heat input and width of the heat-affected zone (HAZ).
  • Reduced residual stresses and related distortion compared to single or double v-groove welds.
  • More-precise control of welding variables.

But Narrow Groove Welding presents a difficulty—seeing what’s going on in the very narrow, quite-deep groove.

Monitoring Down in the Groove

A Weld Camera is the best tool to overcome the weld visibility challenge of Narrow Groove Welding. Because a Weld Camera can image inside the narrow groove, it helps the operator to center the torch in the axis of the joint to be welded, or to guide the torch with respect to one reference side of the groove. Process and quality control are improved because the operator can monitor the weld in real time, continuously checking the weld pool for adequate sidewall fusion and coverage.

In orbital Narrow Groove Welding applications, using a Weld Camera enables on-the-fly adjustments to be made in three degrees of freedom (lateral position; yaw or orientation in the axis of the weld groove; and pitch or trim correction) so that arc-on time can be optimized.

For some welding applications of very high-strength steel alloys, vertical down welds are the only type of weld permitted; others only permit vertical up welds. The result is that many Narrow Groove Welding heads are equipped with symmetrical wire feeds in front of and behind the torch for welding in both directions. As a result, it’s necessary to have a camera in each direction to be able to see the wire tip.

Conclusion

To maximize efficiency in Narrow Groove Welding, Weld Cameras are needed to provide operators with adequate weld visibility to control the process. Particularly if the Weld Camera has the most-advanced technology (e.g., High Dynamic Range imaging), it can substantially improve productivity and quality for fabricators.  

 

Image Courtesy of Arc Machines Inc.

 

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Topics: weld camera, Tube and Pipe welding, GTAW, Narrow Groove Welding

Using a Weld Camera in Hot Wire Gas Tungsten Arc Welding (GTAW)

Posted by Cameron Serles on Thursday, October 10, 2013 @ 04:02 PM

With the development of specialized, automated hot wire equipment, hot wire Gas Tungsten Arc Welding (GTAW) has emerged as a productive, high-quality process for many Narrow Groove Welding applications.

Because hot wire technology is conducive to automation, it fits in well with the trend toward automating GTAW (a.k.a., TIG) processes. In manual GTAW, the hot wire method is largely impractical, but as automation has spread, the popularity of hot wire GTAW has also increased. Industries such as nuclear power generation, oil and gas, and valve manufacturing are increasingly using hot wire GTAW for automated Narrow Groove Welding and hardfacing (overlay/cladding) applications.  

However, automated hot wire GTAW still faces the problem that’s encountered in all automated welding processes —how to control key weld characteristics when they can’t be seen directly. Without a remote weld monitoring solution to see what’s happening with the weld, suitable process and quality control cannot be achieved.

Fortunately, Weld Cameras have advanced along with automated hot wire GTAW technology. The best Weld Cameras can now provide clear, detailed images of a narrow groove weld scene, without slowing the hot wire GTAW process.

The Development of Hot Wire GTAW

Historically, the advantages of the high-quality welds possible with GTAW have been offset by the process’s low deposition rates. But the hot wire method speeds up those rates, making GTAW feasible in many applications where it wasn’t before.

Unlike traditional GTAW, in which the filler wire is added cold and arc energy heats it, hot wire GTAW systems use a second power source to resistance-heat the wire so that it's already near the melting point when it's added to the weld puddle. This results in a much faster travel speed, while also producing nicer-looking weld beads, with little or no sacrifice in weld strength compared to the cold wire method.

 

Hot wire GTAW process

Principles of Hot Wire GTAW

 

The hot wire method has been tried on other welding processes, but its worth in those applications has been limited compared to Laser Beam Welding (LBW) and GTAW, where its increased speed is so important in overcoming the traditional slowness of the process. Automated hot wire GTAW is particularly valuable in Narrow Groove Welding on materials that require high-quality welding processes (e.g., 300 series stainless steel, duplex stainless steels, nickel-based alloys, and reactive metals such as titanium).

The Development of Weld Cameras

The introduction of High Dynamic Range imaging to Weld Cameras has given them the capability to provide good visibility of Narrow Groove Welding—providing fabricators with the tool they need to maximize the benefits of hot wire GTAW.

Unlike standard cameras, which can only image a brightness range of about 50-60 dB, High Dynamic Range cameras can image a brightness range of more than 120 dB—which is enough to simultaneously image both the super-bright arc region and the dark background of a weld. Therefore, with a High Dynamic Range camera integrated onto the weld head, operators can “see” the key weld characteristics during Narrow Groove Welding with no need to slow the process by stopping to change lighting.

Welding automation has numerous benefits, but this operator visibility of the narrow groove weld in real time is necessary to ensure superior-quality welds and maximize productivity. Operators are still smarter than machines!

Conclusion

Hot wire GTAW for Narrow Groove Welding or hardfacing applications is a very promising technology, and its use will likely continue to increase in coming years. But its success is dependent on how well the process can be controlled, and the maximum control can be achieved through in-process operator monitoring of the weld. By far the best solution available to achieve that monitoring is a Weld Camera with High Dynamic Range imaging, directly integrated into the automated hot wire GTAW system. 

 

Image: Katsuyoshi,Hiroshi, M. Toshiharu, and H. Watanabe; Quarterly Journal of the Japan Welding Society.

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Topics: weld camera, welding automation, GTAW, Narrow Groove Welding

Using a Weld Camera for Monitoring GTAW

Posted by Cameron Serles on Thursday, April 25, 2013 @ 10:11 AM

Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by a shielding gas (usually an inert gas such as argon), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. 

A constant-current welding power supply produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma. GTAW is the slowest process in metal joining, but it produces a very high-quality weld, as follows: 

 

GTAW Process

                                                                      (courtesy of commons.wikimedia.org)

Using a Weld Camera with High Dynamic Range imaging for remote monitoring of GTAW, operators benefit by:

  • Confirming that the arc is supplying sufficient heat to melt the work piece and any filler metal that may be necessary.
  • Confirming that the surface of the molten pool and the immediate surrounding parent metal is kept clean of impurities.
  • Confirming that the weld head is tracking the weld seam properly.
  • Confirming that the weld head angle is correct.
  • Ensuring sufficient shielding gas is present around the electrode.

The Challenges

GTAW normally emits light with a consistent amount of brightness, avoiding the light-variation issues faced in other types of welding such as GMAW. The problem with GTAW is that the light spectrum generated is brighter in the Ultraviolet range than other types of welding, making it essential to suppress the UV energy to prevent stray UV light from reaching the camera and making the image brighter than it would otherwise appear to the operator. 

GTAW processes require that the tungsten electrodes never touch the welded metal, in order to prevent contamination of the electrode. As a result, the initiation of the arc is often obtained by a high-voltage spark that could reach several kV in voltage, potentially causing huge amounts of electromagnetic interference. Such huge voltage spikes can kill electronics that aren’t designed for them, such as what might exist in standard cameras. Weld Cameras with more-robust electronics designed to survive such power surges are necessary to survive the tough welding environment

The GTAW welding arc normally generates a consistent brightness that lights up its immediate environment—providing ideal conditions for acquiring an image with a Weld Camera.  However, sometimes GTAW operates with modulated current to the welding arc. The modulation is usually adjusted to suit the type of welding process and can vary hugely—from no modulation at all (e.g., 0 Hz, or a steady pulse of power) to modulation at frequencies as high as 5000 Hz for certain welding processes.

When modulation does occur, the brightness of the welding arc changes significantly—from a bright arc to a much-less-bright arc. The challenge of being able to video such a variation can cause trouble with some Weld Cameras, as they may be set up to see the lower arc brightness, but get saturated on the high arc brightness. A properly designed Weld Camera will be able to see the full range of brightness without loss of arc detail or background information due to saturation.

 

GRAW welding process shown in image from Weld Camera with High Dynamic Range imaging

Weld Image of GTAW

Topics: remote monitoring, weld camera, GTAW

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