Request: The customer produces large-diameter API pipe in an ERW rolling mill. A critical control element in their process is ultrasonic weld inspection. To meet API (American Petroleum Institute) standards, every length of pipe must be inspected for weld defects prior to shipment. When a weld defect is found anywhere along a length of a pipe, the entire pipe is essentially scrap. For that reason, it’s paramount to detect weld defects in the mill immediately after the pipe is created. We decided to create an ultrasonic weld inspection system as a result.

While inspecting, the expensive testing electronics would be at risk of being damaged by passing butt-welds, splits, and cut-outs. Thus, the system would need to be adjustable for the wide range of diameters produced on the mill. It’d also require providing technicians with a means of confirming the test setup over a sample-pipe with known defects. As a result, system would need to package in a very narrow gap between the welder and the seam annealers, as well as be extremely rigid to avoid introducing noise to the testing results. Finally, the inspection system would need to apply a “human-readable” mark to the exterior of the pipe anytime a flaw is detected and anytime the mill is operating with the testing electronics disabled. 

Challenges: Design, build and install an articulation system (UT Bridge) that would package in the available space, adjust to the diameter being processed, and protect the testing-electronics from damage. It would need to incorporate a means of detecting approaching threats and automatically retracting to a safe position. The system would also require to provide a convenient means of conducting & confirming setup, and a means of applying human readable markings to the exterior of the pipe. 

Our Solution: we created a ruggedly constructed cantilevered steel bridge frame. It provides a rigid mounting surface for a ball-screw actuated carriage running horizontally on the bridge. The carriage supports a vertically articulated mounting plate that accommodates pipe diameter change. The carriage also provides a mounting surface for the testing electronics, crash sensors, and integrated fast-retract system. The pipe marking is accommodated by a gravity fed, fast drying ink marking system, which also adjusts for height and diameter. The onboard PLC and a pedestal mounted HMI allows technicians direct control over the bridge for setup and regular operations. The onboard control integrates to both upstream and downstream control and safety systems.