The Xiris Blog

Using Cameras When Welding Spiral Pipe Part 3: Post Weld Inspection

Posted by Cornelius Sawatzky on Monday, December 04, 2017 @ 03:16 PM

Following sub arc welding on the inside and outside of a helically welded pipe, the pipe must undergo inspection to be prepared for further processing or service in the field. This preparation step includes rigorous inspection and testing procedures, repair of defects, and application of anti-corrosion coatings before the pipe enters service.

 

Dec 4 - image 1.jpg

Post-weld Scarfing in helical sub arc welding

Traditionally, post-weld inspection is done manually by an operator who walks around the exterior of the pipe or crawls through it as part of an offline process. The operator is responsible for identifying any weld undercut, incorrect weld wetting angles, or insufficient or excessive weld bead material from the process.  It is not only time consuming, but it relies on the operator to be consistent to be able to catch all defects in the product.

A better solution is to use automatic inspection equipment such as the Xiris WI3000 weld inspection system, which can profile the entire weld bead after the flux has been removed or fallen away to detect problems sooner in the process.  Usually used as an inline inspection tool post-weld, the WI3000 can also be used to provide the operator with feedback to make corrections reducing additional defects while marking the location of a defect to expedite the repair process.

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Laser Bead Profile of a Weld Bead with a Too Steep Slope on the Right Side of the Bead

Information from the laser sensor is transmitted to a single image-processing system, allowing the operator to identify and control the welding parameters.   The end result is a better, more objective measurement of the weld bead inspection process in advance of use of the pipe in the field.

Xiris Automation offers a full suite of products for your helical sub arc welding (HSAW) process. From the control and quality assurance of the initial forming and tacking stage by the XVC-1000, through the remote monitoring of process parameters during full-seam sub arc welding by the XVC-S, and the post-welding and post-scarfing inspection by the WI-3000, Xiris provides operators with the tools they need to prepare the highest-quality products they can.

To learn more about how Xiris Automation’s full suite of turnkey solutions can improve the quality and yield of your HSAW manufacturing process, contact one of our technical specialists today.

 

Topics: High Dynamic Range, Tube and Pipe welding, submerged arc welding

Using Cameras When Welding Spiral Pipe Part 2: Helical Sub Arc Welding

Posted by Peter Serles on Tuesday, October 03, 2017 @ 08:15 AM

One-step Helical (or Spiral) Submerged Arc Welding (HSAW) processes do not use GMAW/GTAW systems to tack the material into pipe form like two- step processes, but rather perform full inner welds using a sub arc welder during the initial forming stage.

This one-step process is advantageous in that it requires less equipment, and therefore less shop floor space, but it results in significantly lower processing speeds compared to the two-step process.

Both one- and two-step HSAW processes use dual-system submerged arc welding with flux recovery systems to perform the complete welds, with a preliminary weld on the inner diameter and a secondary weld on the outer diameter. Using two HSAW systems in parallel allows the weld penetration depths to meet, providing a strong weld in wall thicknesses as large as 1”.

cross-section-dual-sub-arc-welded-seam.pngCross section of Dual Sub Arc Welded Seam [1]

The quality of these welds is paramount to the success of the pipe. With applications in the transportation of oil, natural gas, water, and other flammable and nonflammable liquids, a small defect in the weld seam affects not only the density of the weld—causing higher risk of leaks—but also becomes a major point of corrosion-induced wear. Porosity, thermal cracking, undercut, and insufficient penetration are all critical defects caused by relatively common circumstances during the submerged arc welding process.

Detecting Defects Sooner With HDR Weld Cameras
Various standards organizations such as the American Society of Testing and Materials or the American Water Works Association prescribe hydrostatic testing to 2800 psi / 193 bar, as well as ultrasonic or radiography testing, to ensure the quality of the weld seam for its service life. But these tests determine the quality of the seam in a retroactive way, after the defects have already propagated throughout the tube.

The Xiris Weld Camera for Sub Arc applications, the XVC-S, is an affordable turnkey solution for monitoring the sub arc welding process. The XVC-S features an out-of-the box solution with integrated lighting, graphical-overlay-producing crosshairs, and a rugged housing suitable for the welding environment.

With on-screen monitoring tools, operators can easily identify and correct any deviations from standard operating procedures, including insufficient flux supply, misalignment of the torch or seam, and damage to the weld tip. The remote viewing monitor can display multiple processes, allowing a single operator to monitor the quality of the inner and outer sub arc welding processes simultaneously.

operator-remote-monitoring-sub-arc-welding-process.jpgOperator remotely monitoring a sub arc welding process

The small size of the XVC-S camera allows it to be easily integrated into an existing sub arc welding mount and the high-voltage and high-temperature resistant design, combined with the built-in solid-state lighting, allows high-quality images to be produced even in the harshest environments. By ensuring the quality of the weld during the sub arc welding process itself, defects can be caught sooner and corrected before the quality of the entire pipe length is compromised—saving time, money, and resources to provide an overall more-efficient process.

[1] RIBEIRO, Anderson Clayton Nascimento; HENEIN, Hani; IVEY, Douglas G. and BRANDI, Sergio Duarte. Evaluation of AH36 microalloyed steel welded joint by submerged arc welding process with one and two wires. Mat. Res. [online]. 2016, vol.19, n.1 [cited 2017-06-22], pp.143-152.

Topics: High Dynamic Range, Tube and Pipe welding, submerged arc welding

Using Cameras When Welding Spiral Pipe: Processing and Tacking

Posted by Cameron Serles on Wednesday, August 16, 2017 @ 10:18 AM

Helical (or Spiral) Submerged Arc Welding (HSAW) allows for larger, thinner-wall welded pipe, but this benefit has a cost—a higher chance of welding defects.

By enabling greater visibility and control during processing and tacking, high dynamic range (HDR) weld cameras are a powerful tool to counter this risk.

The Advantages of HSAW

HSAW has a unique capability for producing large diameter pipes for flammable and nonflammable liquid transportation. While longitudinal pipe welding is limited to approximately 42” (1.1 m) outer diameter due to the size of the feedstock sheet, helical pipe welding is only limited by the size of the equipment, allowing pipes as large as 140” (3.6 m) outer diameter to be manufactured.  

Helically welded pipe also has a distinct advantage over longitudinally welded pipe because the radial stress in the weld seam is not concentrated along a single axis but instead rotates around the circumference of the pipe, creating a more-even stress distribution. This advantage allows for thinner tube wall construction using more economical, non-high-strength materials.

Limiting Defects with HDR Weld Cameras

Spiral welded pipe is made using either one-stage or two-stage weld processing.  While both processes begin with the incoming skelp coil of material being unwound, flattened, trimmed, squared, and then fed into the forming  stage, in one-stage processing, the forming process is immediately followed by simultaneous inside and outside Submerged Arc Welding.

In two-stage processing, the material is formed and tack welded into the pipe body shape by a gas metal welder prior to the Submerged Arc Welding process. The tack welding stage is critical for the quality of the pipe because misalignment of the initial tack will cause defects when further processed during the Submerged Arc Welding stage. Numerous factors can cause misalignment, including defects in the metallurgical properties of the feedstock, gaps between sheets, misalignment of the welding heads, or dull tooling during the processing of the skelp coil.

With the latest in camera and software technology, the Xiris XVC-1000e high-dynamic-range weld camera permits the operator to see the spiral pipe feedstock,  the weld head, and torch location relative to the weld seam during the welding process. By monitoring the images directly, an operator can make adjustments to the material inputs or torch position to quickly correct the fault before the defect propagates throughout the length of the weld.  The camera’s robust, IP65-rated enclosure allows it to survive the harsh environments of HSAW pipe mills.

Additionally, the XVC-1000e can be used with Xiris’ seam tracking software, as shown in the figure below. The seam tracker software identifies the location of the welding head and the arc contact with the material and the material seam, detecting fluctuations in alignment. With such software, out-of-alignment conditions can automatically alert the operator to make process-control adjustments or even provide closed-loop feedback to automatically move the torch back into position.

XVC-1000e with Seam Tracker Software

Summary

Adding a Xiris XVC-1000e weld camera to an HSAW pipe mill can help operators monitor the feedstock material forming process and alignment to the welding torch, ensuring that minimal defects occur during the preliminary material processing and forming stages. In so doing, pipe weld quality can be improved, reducing the risk that weld defects will propagate down the pipe mill and make it to the customer.

Topics: Tube and Pipe welding, submerged arc welding, weld seam alignment

Post Scarf Inspection of Automotive Fuel Line Tubing

Posted by Cornelius Sawatzky on Wednesday, June 14, 2017 @ 04:00 AM

Fuel line tubing is typically manufactured on an ERW welding mill similar to traditional seam welded tubing.  Once the tube has been welded, it moves down the mill for further in-line processing that may include reducing, sizing, annealing and coating processes to meet the customer’s needs.

Fuel line tubing must be perfectly round in order to create a good seal when compression fittings are applied to it. The tube surface must be free from longitudinal scratches, grooves or beads in order to prevent a leak path from developing at the interface point of the fittings.

Immediately after the fuel line tube has been welded and before any further in-line processing is done, the weld bead must be scarfed (the process whereby the weld bead is cut off with a knife).  Unfortunately, the scarfing process can be the primary contributor to creating a leak path on a compression fitting because:

1. Insufficient scarfing can leave a small portion of the weld bead protruding from the     surface of the tube. This may be on either one or both sides of the weld bead where scarfing tool positioning is critical.

June 14 Image 1.jpg

Insufficient Scarfing

2. Excessive scarfing may look perfectly round to the human eye however a non-uniform wall thickness may be lurking below the surface. What is not always apparent and usually only observed during thorough end cut inspection is a thinned portion of the tubing wall that may compromise the integrity of the tube. The reducing process applies enough external force to the tube that the tube may buckle or collapse, causing a deep surface groove.


June 14 Image 2.jpg

Excessive Scarfing

3. A mismatched setup may also be a contributor to a non-uniform wall thickness. The scarfing tool may cut the bead on the outside diameter so that it looks perfectly round to the human eye, disguising the compromised wall thickness below the surface. Sufficient mismatch conditions will most certainly cause the tube to split on end forming later in the fabrication process.

June 14 Image 3.jpgMismatched Defect, Post Scarfing

The Xiris WI2000/3000 Weld Inspection System uses laser-based imaging techniques to continually monitor the scarf zone for any variations in the scarf height, seam mismatch and possible scarf tool wear or chips that may cause a longitudinal line on the tube. By detecting and responding to these conditions proactively, a mill operator is able to reduce the chance of a leak path on the tube and avoid an unplanned stoppage to the mill due to a tube collapse during the reducing process.

For more information on how a Xiris Weld Inspection System can enhance your scarfing processes visit Xiris.com 

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Topics: quality control, Tube and Pipe welding, laser-based monitoring, scarfing, productivity tools, automotive

Why Weld Cameras are Essential when Welding Large Pipe

Posted by Cameron Serles on Monday, April 03, 2017 @ 12:56 PM

 

 

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Large Pipe Fabrication

Welding large pipes using either Submerged Arc or Open Arc welding processes may pose a number of problems, such as:

  • poor alignment of torch to seam
  • improper levels or placement of shielding gas or flux
  • improper joint preparation
  • jammed wire feeders
  • wrong welding power levels

to name just a few.

 In order to avoid these problems and ensure the highest possible quality, welding processes must be monitored closely.  When automated welding processes were first introduced, fabricators stationed an operator in a chair atop a welding machine, such as a column and boom welder, to visually monitor the welding process directly.  Surprisingly, this is still a widely used approach to weld monitoring!

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An empty chair waiting for the operator….

Even today, there are fabricators who are unfamiliar with automated inspection process and are forced to place an operator on a chair high above the welded pipe to monitor the welding process.  This is a health and safety problem waiting to happen!  Not only does the operator face fume inhalation, they risk injury from moving equipment, inadequate protection and dangerous heights.

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Can you see the Operator monitoring the process?

In addition to the safety concerns, work breaks are a major drain on productivity.  Just think of the production time lost while moving the gantry robot or hoisting equipment down so that the operator can safely exit the equipment at ground level, not to mention the idle time until the operator returns to their position.

Apr 3 image 4.png

Or Here?

A Better Solution

The better solution is to use a remote monitoring weld camera installed at the weld head that can be viewed from as far as 100 m away.  Operators are on the production floor, removed from the welding process but still able to see all the details of a welding process.   Watch the video below, created by LJ Welding in Edmonton, Alberta, Canada, for an excellent demonstration of how weld cameras are being used in the field:

 Apr 3 image 5-1.png

 

You can visit our

WELD VIDEO LIBRARY

for dozens of examples of the camera in action. 

For more information on how Xiris Weld Cameras can enhance your weld processes visit Xiris.com or REQUEST A DEMONSTRATON 

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Topics: quality control, Xiris, welding, weld safety, Tube and Pipe welding, productivity tools

How to Reduce Customer Returns from your Tube Mill

Posted by Cameron Serles on Tuesday, February 14, 2017 @ 04:00 AM

When a customer refuses to accept a shipment because of a quality problem, the cost escalates as soon as the tube leaves the plant. The cost of customer returns includes all product that gets returned from, rejected by or credited to a customer. It also includes the expense of sorting, investigations, meetings, reporting, shipping, handling and containment.  The tube producer may have to rework the product until it meets customer expectations, scrap it or, worse, send a team to the customer’s site to inspect each piece manually.  By adding weld inspection into a tube production line, the rate of defect detection will be higher as the weld inspection system will be able to detect, at a high level of accuracy, defects that are not easily detected by NDT equipment or manual operators.  With higher defect detection rates, better quality product will be shipped, ultimately reducing customer returns.

Feb 13 Blog Image 1.jpg(photo courtesy of www.demacmedia.com)

 

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For more information on how Xiris Weld Cameras can help monitor your weld processes, visit Xiris.com or sign up to receive the Weld Video of the Month 

Topics: quality control, Xiris, welding, Tube and Pipe welding, ROI, return on investment, productivity tools

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