-New equipment Hot slab measurement system A dedicated hot slab measurement system has been developed by Integrated Photomatrix. It enables the length of hot steel slabs, at temperatures of around 800°C, to be optically measured to ___ 5 mm. Typically this takes place while the 5-10 m slabs are on the roller table, after leaving the flame cutter and before proceeding to the reheat furnace.

The system involves the posit ioning of a single 80 mm low-distort ion lens camera over the slab's leading edge at a forward vanishing stop. Additionally, three 40 mm low-distort ion lens cameras, each with a 2000 mm field of vision, are mounted over the trail ing end of the slab.

Self radiation from the slab is harnessed to project an image onto linear arrays in the cameras, which are encased water-cooled housings. In the event of the slab temperature being too low to emit sufficient light, a warning system wil l alert the operator. Calibration light sources are mounted below the roller table.

The single forward camera, with a field of vision of

900 mm, measures the distance between the slab's leading edge and the nominal stop position. The three rear cameras measure the position of the trail ing edge with reference to the same nominal stop position, and the camera signals are processed on a microprocessor image analyser to calculate the slab length.

A wal l -mounted image analyser incorporates an oscil loscope and an IPL-designed software package for length measurement, calibration, temperature correction and data transfer by analogue signal to a Modicon 984 PLC. A pyrometer is incorporated to measure the temperature of the slab to al low the 'cold' length to be computed.

Integrated Photomatrix Limited, The Grove Trading Estate, Dorchester, Dorset DT1 1SY, UK

Automated imaging for rocket motor welds A $1.3 mil l ion contract from Babcock and Wilcox Aerospace Components Division has been awarded to f ie - Imag ing Research ( B I n ) to design, build and install an automated digital radiography (DR)

l off IPL camera for slab Concaster pulpit front end measurement

and pyrometer for slab End temperature pet" strand marking

/ machine Current ladle 3 off IPL cameras n~r k.~>-..~ I of molten steel strand for slab 'tail'- ~ _ ~ ' ~ , , , ~ = ~ ' ' " ~ Slabs to

end' m~urement i , ~ i ~ ~ ~ stockyard Next ladle of / molten steel fi'om steel making plant Tun dish I I

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Slab flame cutters

Mould

Slab cooling

Layout of the non-contact hot slab measurement system from Integrated Photomatrix

inspection system to be used in NASA's advanced solid rocket motor programme. Each case segment is 3.8 m in diameter, 10.7 m long and has steel walls 16 mm thick. Three segments are required per rocket motor and there are 11 circumferential welds per motor. The system wil l be able to inspect one 12 m long circumferential weld in 6.5 h to a sensitivity of 2-1T.

The design incorporates a 225 kV X-ray source and a 51 mm long, 2048-channel charge coupled device (CCD) detector wi th f IR designed scintillators. A manipulator controls case rotation and axial motion during scanning. Separate source and detector adjustments are also possible.

The operator initiates and controls scanning using an ACTIS 1000 computer system. This UNIX based system has a PC 396 bus and i860 image processor. Weld integrity is monitored on-l ine and the operator can automatically mark the location of features of interest. Weld images are viewed on two 1024 x 1280 pixel monitors, one for real-time X-ray data collection and one for image retrieval, v iewing and enhancement. Data storage is provided by a 1 Gbyte optical disc, a 700 Mbyte hard drive, a 1.44 Mbyte 3.5 inch f loppy drive, and a 1 50 Mbyte 1 /4 inch tape drive. The image data base is interfaced via Ethernet to computer systems at Babcock & Wilcox.

System controls include a six-axis closed loop DC serve control, wi th quadrature encoder inputs for position and speed. The operator has local system control via a gantry control processor. Addit ional remote control is available from the operator console located in a control room.

f ie-Imaging Research Inc, 425 Barclay Boulevard, Lincolnshire, IL 60069, USA

280 N DT& E International October 1 991