Research Of An Intelligent Electromagnetic Nondestructive Testing System

Low-alloy steel such as 40Cr has fine comprehensive mechanical quality after being quenched and tempered, and it is widely used in production, which makes inspection and control of its quality necessary. Hardness is its most important capacities, whereas, because of hardness overproof caused by some reasons, during the practical quenching and temping process, low-alloy steel can't satisfy the need of producing technology. So the research of intelligent electromagnetic nondestructive testing system that can inspect hardness effectively and vapidly is significant for improving the quality of steel and iron product and productivity.The paper describes the design thought, inspection principle of the intelligent electromagnetic nondestructive testing system (WFY-1 instrument), introduces the whole design procedure of analogue system, digital system and software system. Due to sensitive reactions to multiple parameters, the testing instrument must be able to restrain influence of multiple disturbances. The double-channel perpendicular coherent decomposing experimental device adopts the synchronous demodulation, by analyzing and processing the signals, separating useful hardness signals from multiple disturbances. Using the device, we tested two groups of samples that included the steel of 40Cr and the steel of 65Mn, got a single-valued relationship between displayed value on the device and tempering hardness. In addition, according to appliant characteristics of electromagnetic nondestructive testing for steel and iron, on the basis of characteristic parameters taken out of WGQ-268 electromagnetic nondestructive testing instrument, we established an arithmetic model about quality test for steel and iron, integrating pattern recognition method, we performed quality test for hardness of GCr15 bearing steel and the result is satisfactory.