Seamless Steel Pipe Ultrasonic Thickness Measurement Process And Device Research

This paper introduces the background and significance of the project and a brief overview of the technique and equipments used in the thickness measurement of steel tube is given. By evaluating various methods and techniques, the one using ultrasonic wave is chosen. With the technique, a thickness measurement equipment which is suitable for the production condition of seamless steel tube at home is developed.According to the technology requirement, various methods and techniques are compared at first. Combining with the production situation at present, a thickness measurement method of "part-immersion" and measuring technique in which the steel tube does not rotate and the probe is static are chosen. Based on the selected technique, the design of the whole equipment is discussed. The structure of this equipment which consists of mechanical system, coupling system, measuring system and control system is determinated through discussing. The device designed can fulfill high-speed automatic measuring and visual monitoring, save and query the measurement data automatically, display the thickness curve visually, and give an alarm automatically. It has low cost and strong usability.Using the theory of ultrasonic wave and experiments, analysis and computation using the theory are carried out in the design process of coupling system which is the critical part of the whole equipment in terms of the selected technique. The determination of the coupling layer depth is discussed, the value of the depth is gained through computation. Based on the ultrasonic theory, the relation equation among diameter of the probe, repetition frequency, measuring speed and the resolution is summed up. With the help of this equation, the number of probes used and their distribution are determinated. At last, the measuring container, sealing structure and the water-processing sub-system which are parts of the coupling system are also designed, and the experiments are done to improve the design.This equipment has been applied to the production successfully. Compared to similar technique at home and abroad, it is easy to design and make, the transfer and receiving system of the signal is very simple, it can be also applied to the steel tube with big diameter. The cost, fault rate and the fee for maintenance is low.