Kawasaki Steel Corporation has developed an on-line wall thickness gage with joint efforts of Fuji Electric Co., Ltd.. The development took four calender years. This gage was developed for the first time in the world, and started on-line use in October, 1981.
This gage utilizes γ-rays and is possible to measure continuously the wall thickness along the longitudinal direction of pipe to an accuracy of 0.1 mm and a response speed of 0.1 second with no physical touch. Principle of measurement of this gage is named multi-beam method which is based on a premise that three γ-ray beams forming triangular shape cross each other within the pipe wall thickness.The wall thickness gage utilyzes micro computer systems effectively. Particurally analyzing the twist angle of the wall thickness deviation, FFT (Fast Fourier Transformer) was used at first time for on-line analysis.
With the running of this gage system, the suitable action on the wall thickness control has been established in seamless tube production line. As a result, this gage system has advanced the new tube production technology and improved the dimensional quality of seamless tube.
