The Ultromatic Detecting System Design Of Ductile Iron Pipe Thickness And Nodularity

Centrifugal casting ductile iron pipe is widely used in water,gas,oil transmission for it's merits of high intension,good tenacity,thin pipe wall and so on. In order to ensure the security of the transmission, the quality of the ductile iron pipe must be detected before used. The thickness and nodularity have the greatest impact on the quality in all kinds of parameters of ductile iron pipe, in which the wall thickness directly affects the carrying capacity. The uneven or partially thin thickness will cause the accident of pipe burst; nodularity directly affects the mechanical property of ductile iron pipe, such as intension, tensile property, abrasion resistance and so on, the low nodularity reduces these properties.At present, the usual non-destructive examination equipments mainly include non-destructive flaw detector,thickness detector,nodularity detector and so on.These equipments mostly only detect one parameter, and it only suit to manual single point test, and can not detect the thickness and nodularity atomaticly, fully and fastly at the same time.On the basis of close study of the traditional non-destructive detecting principle of thickness and nodularity, the property of the ductile iron pipe and the process of the production line, we design the detecting system to atomaticly, fully and fastly detect the thickness and nodularity at the same time, vividly show the thickness and nodularity results, accurately judge the result, and automatically mark the abnormal parts of ductile iron pipe. This system is mainly composed of host and save computer, and realized from hardware and software separately.In software, based on the VC6.0 platform, we process the collected ultrasonic echo data with some digital signal processing methods, such as filtering, difference, spectral estimation and so on, then get the velocity of ultrasonic and the wall thickness and nodularity of the ductile iron pipe. In additon, we designed the user operation and display interface in the host computer to visually show the results of measurement and judgment, and to set the parameters of ultrasonic card and serial communication. In hardware, we use ultrasonic card to transmit and collect the ultrasonic, and use CPLD as the core of control to control modules of motor, distance detector, marker, temperature detector and son on, and to communicate to the host with serial port. From the practical testing results, this detecting system can atomaticly, fully and fastly detect the thickness and nodularity at the same time, and can accurately judge the measuring results, further more, the precision and stability of the measuring results meet the requirements.