The technology of the dimension and shape measurement of steel products is one of the most importantΔbases on the quality control of steel production process.
Kawasaki Steel Corporation has developed an excellent measurement technique which employs "water column method" to meet with strict requirements such as inconvenient environment, on-line continuous measurement and others.
The water column method is based on two kinds of principles. One is the ultrasonic measurement. Ultrasonic pulses are transmitted and received via water column to and from the object. The distance to the object and its thickness can be obtained from time intervals between echo pulses. The other is the electric resistance measurement. A constant electric current is fed to a water column which connects an electrically insulated fixed nozzle with an earthed object. By measuring the electric potential of the nozzle, the length of the water column, which shows one of the factors of the object's shape, can be known.
Five of on-line applications are as follows:
1) Thickness and outer/inner diameters measuring system for medium seamless pipes.
2) The same system for small seamless pipes as mentioned above.
3) Width gauge for hot sheet bar at hot strip mill.
4) Edger roll position sensor at heavy plate mill.
5) Flatness measuring system for hot strip.
