Skelp Inspection

As demands for higher tensile steel increase, width and edge tolerances are important since high-strength material will not form like softer grade steel. Factors within a tube and pipe producer’s control are slit edge and width quality, which can be inspected offline or online.

Tube & Pipe Producers Challenge

Bad steel coil does exist, the yield strength could vary, the edges could be damaged, the skelp width might vary along the length of the coil, just to name the most common visual problems. Achieving a quality weld requires starting with good edges. In manufacturing tube and pipe using ERW, Plasma, TIG or Laser processes, this is a critical factor towards consistent yield.

Preparing the edge of a metal strip properly before it enters a tube mill makes a huge difference in the quality of the final product. Perfect edges are almost impossible to obtain consistently by trimming process, either by rotary side trimming single-width coils or side trimming and slitting master coils. Slitting introduces affects surface appearance, width dimension, flatness, camber, and edge wave. These may affect the final quality and acceptability of the pipe or tube being made.

Edges that don’t smooth out in the fin passes cannot be presented parallel to one another at the weld point. They will heat unevenly, and the result will be periodic or continuous weld splits.

Skelp Edge Inspection Solution

Collecting comparative data over time is a good starting point to develop statistical process control (SPC) for skelp and edge conditions. However one cannot expect an operator to begin logging measurement data.

Using a laser profile sensor the laser line generates a set of world data points which are then used by the application software to detect edge and skelp faults. The system identifies:

• Skelp width
• Skelp thickness
• Edge wave and edge finish
• Burr
• Shear angle
• Shear to break ratio

These two images represent a bad edge. The image above shows the shear zone is wider than the break zone and excess material exists at the break point.

On the second image the resultant scan shows that edge finish is bad, which could be damage to the rotary wheel.

The skelp inspection system comes loaded with an SPC system under the hood as well. Important features are:

• Collect data
• Calculate metrics
• Monitor in real-time
• Allow for business rules to initiate events for Out of tolerance
• Store to database for traceability
• Publish to report for production and quality

Alerts are generated based upon a defined set of production rules. These rules define how the system responds to events. The events can alert mill operators via, screen indicator, light tower, marking system. The event can also trigger a corrective action list to appear or initiate a shut down sequence if the event is severe.

Having the ability to view the monitoring data in a summarized manner allows for quicker decision making and also allows communication of the skelp metrics to the operations and production teams. The reporting system can either be driven manually or by an automated process based upon an event, a schedule or business rule trigger. The reports are customized according to the needs of the client.

Adhering to a good quality program can lead to a better business process. Not only does compliance keep products and services consistent, fit for use the first time, but it also keeps the company running conveniently and smoothly when quality plays is role effectively. Give us a call today to discuss another way in which we are helping manufacturing reduce liability and increase profit.