NDT system Eliminates Cold Welds, reduces scrap by 0.7% for ERW - HFI tube producer

Dec. 30, 2011 - PRLog -- In the modern world of tube and pipe manufacturing, it depends upon producing the right product for the least cost.   New innovations regularly receive attention when they can increase a mill’s productivity and efficiency.  Cutting edge techniques have started to streamline a market that once required tedious and time-consuming efforts to ensure quality.

As a supplier to tier 1, quality is paramount to successful programs.  High value and of key importance for this ERW / HFI tube producer, is the ability for the NDT weld inspection system to detect cold welds.

Scanning at 400Hz, the sensor takes cross sectional slices of the hot weld and stitches the data back together to form the visual thermal field.  The thermal data is then used to calculate a set of deterministic parameters for monitoring of disturbances in the thermal field.  In the image the parameter field exceeded the control limit and  flagged the fault which in turn generated the alarm for the ERW mill marking system.  

Says the production manager of ERW mill, "it doesn’t happen overnight, over
the past several months we have been tuning and dialing in the parameters and really starting to understand our process. We are running the threshold limits fairly tight and we have seen a net reduction in our scrap rate.”

DEFECT UNDECTED BY EDDY CURRENT
Many parameters can affect the eddy current responses. This means that the signal
from a desired material characteristic  may be masked by an unwanted parameter.
Tests are generally restricted to surface-breaking conditions and slightly subsurface flaws.  In this particular case, the flaw was not detected by the eddy current system
and the tube length with the flaw was received at the customer’s door.

EVOLUTION OF WELD INFORMATION FOR NDT
Defects usually are classified into two categories—major flaws that can cause tube and pipe failure and minor variances that have no effect on tube or pipe use.  Tube and pipe producers are constantly managing material costs, yield, efficiency and quality to improve profitability, acquire and retain clients and mitigate liability costs.  The costs of shipping defective product are difficult to quantify. However, the risks and costs associated with repairs, loss of customers, or subsequent legal action are potentially huge—they are the main impetus for installing NDT equipment in the first place.

For tube and pipe production applications, which require high throughput speeds for maximum profitability traditional NDT equipment such as eddy current testing is used to detecting small, short, incomplete welds; inclusions; voids; or cavities. Ultrasonic testing normally is used to find long, continuous defects, such as incomplete seam welds.

The Thermal Profile System is based on the recording and the evaluation of the thermal radiation which is emitted by a solidifying welded seam.   Operating at 400Hz, the system can scan on tube and pipe mills to a speed of 180m/min.  As a result, disturbances can be recognized of dimension less than 1 mm in the thermal signature across a range from approx. 750 °C to about 1400 °C.

To view additional detail and video about this system follow this link:
http://www.invisuale.com/solutions/tube-and-pipe-technolo...

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Pierre Huot founded Invisual E Inc. in response to a desire to implement his vision to the market for identified needs for manufacturing. Huot's adherence to a customer-driven development approach combined with his strategic abilities helping OEM, integrators and manufacturers deliver improvements on key objectives to build brands, expand markets and grow revenues through the implementation of control systems, process improvement and quality management systems

Huot possesses an MBA from the Richard Ivey School of Business and a bachelor's degree in chemical engineering from the University of Ottawa. He is the author of several published case studies and white papers.