The Xiris Blog

How to Detect Scarf Tool Wear on a Tube Mill

Posted by Cameron Serles on Thursday, December 13, 2018 @ 11:00 AM

During tube production, immediately after the tube has been welded and before any further in-line processing is done, the weld bead must be scarfed off the tube. Scarfing is the process whereby the weld bead is cut off with a knife, or scarfing tool.  Unfortunately, if the scarfing tool is not done properly, the tube may not meet end user customer specifications because of a rough surface left behind by the scarf tool.  The result can be the primary contributor to creating a leak path on a compression fitting.

Using a surface profiling tool such as the Xiris WI2000, the scarf defect measurement can be used to detect how well the scarfing tool is cutting the weld bead and indicate the amount of scarf tool wear. 

Scarf tool wear describes the gradual failure condition of a scarf cutting tool on a tube mill as a result of ongoing use.  It can occur either as flank wear in which the portion of the scarf tool in contact with the welded tube erodes over time sometimes causing a ridge to be left behind in the scarf zone; or as crater wear, in which contact with chips of weld bead erodes the rake face of the tool causing an uneven cut surface; or a cluster of weld bead material building up on the face of the tool causing it to dredge a groove in the scarf zone. These conditions are somewhat normal for tool wear, and they do not seriously degrade the use of the scarf tool until it becomes serious enough to cause a scarf tool cutting edge failure that may be a concern for a potential leak path for the tube in its final use.

The scarf defect measurement on the WI2000 looks for any significant deviations in surface height above or below the ideal scarf surface.  The Scarf Defect will detect the absolute value of the largest defect on the scarf surface.  Any significant amount of scarf tool wear could reduce the specifications and performance of the final tube, especially for some automotive applications where tight assembly requirements or a smooth, scratch free surface is required.

Scarf Defect_2017-01

The Definition of a Scarf Tool Wear: The scarf plane can be defined as the straight line drawn between the left and right scarf edges.  Any detected features above or below the scarf plane, are measured as a scarf defect.  The actual amount of wear is defined as the distance from the scarf plane measured perpendicularly to the scarf plane.

If you have any questions about our profile inspections for tube and pipe, please feel free to contact us. 

 

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Topics: tube mill, tubedefects, WI-2000p, defects, tube, pipe, scarfing, bead height, Tube and Pipe welding, quality control

Detecting Bead Ripple During Tube Manufacturing

Posted by Cameron Serles on Friday, October 05, 2018 @ 11:45 AM

Lighter wall mild steel pipe production requires bead height monitoring for bead ripple. Bead ripple is a condition sometimes associated with a weld process that is too hot and may result in longitudinal weld cracks.  Bead ripples appear along the length of the weld bead as undulations with measurable differences in height by as much as 1/8” (3 mm).  Often the height of the bead ripple on a welded pipe is a function of the heat that has gone into the weld process:  the higher the heat, the greater the height of the bead ripple. In most applications, a weld bead should have a smooth, consistent height as an indicator of a stable weld process.

Bead Ripple1An image of a weld bead with bead ripple

In some applications, a weld bead ripple can be desired, such as in certain coated steel products. This ensures that all contaminants from the area of the weld have been squeezed out, preventing potential inclusions from occurring in the weld bead, which would result in compromised weld quality.

By measuring the bead height on a weld bead over a period of time using a laser based triangulation system , an indication of the smoothness of the weld bead can be made.  By calculating ongoing historical statistics of the head height (e.g. min/max, average, standard deviation), an indication of smoothness of the weld bead or bead ripple can be made.  Tolerances of the amount of smoothness or ripple can be set to match the process and when exceeded, an alarm can be set.

Bead Ripple Detection1 Measuring the weld bead height over successive images can detect bead ripple over time

Topics: tube mill, tubedefects, productivity tools, tube, bead height, Tube and Pipe welding, quality control

Monitoring Tube and Pipe Production to Find the TOE ANGLE

Posted by Cameron Serles on Tuesday, September 02, 2014 @ 04:30 PM

 Recent advancements in machine vision technology have made a new type of inspection, capable of finding defects related to the forming and welding area of a tube or pipe.  The result is improved quality assurance and process control on the production line.  The new inspection device is a laser-based triangulation system that measures the outside contour of a tube or pipe in the vicinity of its weld. 

Typically NDT (non-destructive testing) systems are placed at the end of a production as a final check.  However, the laser inspection system can be placed directly after the weld box.  This system can let operators know what is changing in their welding process, allowing them to perform corrective action before significant scrap occurs. This capacity is especially helpful for a closely monitored measurement on ERW/HFI production mills:  the Toe Angle.

The Bead Slop Angle

The Left and Right Bead Slope Angles are measured in degrees at either edge of the weld bead, and represent the angle subtended by a line that follows the contour of the weld bead on either side and a horizontal line.  Also referred to as the Toe Angle, it can indicate the strength of the weld, and the correct forming of the parent material during the creation of the weld, particularly on an ERW/HF process.  A forming problem could be detected because of a larger or smaller than normal slope angle.  It is important to measure both the left and right slope angles separately. This is because the forming of the parent material could be asymmetric on a pipe mill, causing the slope angles to be different on either side of the weld bead, and thereby indicating a forming problem.

als;kdgjdsa;lghfdag resized 600The Bead Slope Angle or Toe Angle, measured in degrees from the horizontal.

 

How the WI2000p System Measures the Bead Slope, or Toe Angle

Xiris Automation Inc. has developed a non-destructive inspection system called the WI2000p Weld Inspection System. The WI2000p includes a laser line, and a camera with an optical axis that is offset to the axis of the laser line by an “offset angle”.  The WI2000p creates a visible cross-section of the tube by projecting the laser line on to the tube, and capturing an image of the line using the camera.  The resulting image shows a profile of the tube surface as if it were cut in cross section.  If a tube is the ideal round, the laser image will represent a section of an ellipse and any anomaly such as the bead can be mathematically detected and the bead slope, measured. 

The WI2000p bases all of its measurements on the differences between the actual laser profile line (seen by the camera), and the ideal mathematical profile based on the tube parameters.  By knowing the position of the actual laser profile, the ideal profile, and the size of the pixels in the image, the WI2000p can detect weld bead profile defects that often escape detection by other quality tools such as Eddy Current testing, or Ultrasonic Testing techniques.

Conclusion

Overall, laser-based 3D imaging systems, such as the WI2000p from Xiris, offer an excellent measurement option for tube mill owners/operators who want additional, real-time monitoring of weld features. They can be used in a proactive manner, warning operators what is changing in their welding process so that they can perform corrective action before significant scrap occurs. Laser--based 3D imaging systems can operate on any type of material, regardless of its reflectance or magnetic properties, using a single head to perform the measurement.

Topics: camera placement, welding instruction, Tube and Pipe welding, bead height, bead roll

Monitoring Tube and Pipe Production to Find BEAD HEIGHT Defects

Posted by Cornelius Sawatzky on Tuesday, April 08, 2014 @ 11:01 AM

Recent advancements in machine vision technology have made a new type of inspection able to see defects related to the forming and welding area of a tube or pipe.  The result is improved quality assurance and process control on the production line.  The new type of inspection device is a laser-based triangulation system that measures the outside contour of a tube or pipe in the vicinity of its weld. 

Typically NDT systems are placed at the end of a production as a final check.  However, the laser inspection system can be placed directly after the weld box.  This system can let operators know what is changing in their welding process, allowing them to perform corrective action before significant scrap occurs. This capacity is especially helpful for one of the most common defects found across all types of Tube manufacturing: Tube Bead Height Defects. 

 

The Bead Height Defect (Raised or Sunken Welds)

The material in the bead area may rise on top of the tube parent material surface (known as a “raised weld”) or drop below it (known as a “sunken weld”), depending on the compression force applied, the metallurgy of the material and the welding process parameters.

A sunken weld defect is a visibly significant and quality critical defect that could create weakness in the tube along the bead.  While a raised weld defect may not be considered as an important a defect (as it can be ground off later), it can indicate quality problems in the setup of the welding process.

The bead measurement is defined as the largest absolute value of a raised or sunken weld.  Calculating the bead metric in this way helps to determine the height of the tube material that needs to be ground off to smooth the profile (and restore the cylindrical shape, as required).  In cases where there exists a mismatch defect at the same time, the bead metric will include the mismatch measurement and will report the total loss of the material thickness after grinding.

April 08.14 Blog Bead Height resized 600

The Bead Height Defect, where “h” = the height of the defect.

 

How the WI2000p System Measures the Bead Height Defects

Xiris Automation Inc. has developed a non-destructive inspection system called the WI2000p Weld Inspection System. The WI2000p  includes  a laser line and a camera whose optical axis is offset to the axis of the laser line by an “offset angle”.  The WI2000p creates a visible cross-section of the tube by projecting the laser line on to the tube and capturing an image of the line using the camera. The resulting image shows a  profile of the tube surface as if it were cut in cross section.  If a tube is ideally round, the laser image will represent a section of an ellipse and any anomaly such as Bead Height defects can be mathematically detected. 

The WI2000p bases all of its measurements on the differences between the actual laser profile line seen by the camera, and the ideal mathematical profile based on the tube parameters.  By knowing the position of the actual laser profile, the ideal profile, and the size of the pixels in the image, the WI2000p can detect Bead Height profile defects that often escape detection by other quality tools such as Eddy Current testing, or Ultrasonic Testing techniques

 

Conclusion

A new technique for detecting Bead Height defects on welded Tube and Pipe has been developed by Xiris and is known as the WI2000p weld inspection system.  The WI2000p system is a laser based inspection system that is capable of detecting Bead Height defects immediately after welding to alert the operator of a defect in time to minimize rejects.  The result is improved quality, fewer field defects and a more reliable method for the operator to optimize the welding process.

Topics: weld inspection, High Dynamic Range, Laser welding, Tube and Pipe welding, image processing, quality control, laser-based monitoring, weld camera, Pipe Cladding, welding defect, bead height

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