AN ULTRASONIC INSPECTION SYSTEM TO DETECT INTERNAL PIPES IN HOT STEEL BLOOM

The experimental pressure contact system with a single transducer has been developed to detect internalpipes and measure ultrasonic wave velocities at temperatures up to 1120℃ and 1300℃,respectively.In thispaper,the design of the system and the special hardware and software about the inspection and the signalprocessing are described;the relation between the echo amplitude and the pressure exerted is analysed,as wellas the formulas and some of the experimental results of pipe detecting are also given.An application has beenmade for a patent.     

高温钢声速与声速滞后现象

本文给出了1200℃以下钢的纵波声速随温度变化的关系曲线,讨论了在加热与冷却过程中声速变化的规律性与声速滞后现象产生的原因是由于相变及其弹性系数比晶内小的晶界对质点位移的影响。同时指出这种现象的发现有利于透过声同物质的相互作用来研究奥氏相变,并有可能借助于声速-温度曲线推断出该种钢的奥氏相变温度,特别是A_(r1)和A_(r3)。本文所得结论,在高温钢坯超声检测中对缺陷定位及避开声速随温度发生陡变区域有重要指导意义。     

高温钢坯缩孔超声检测系统

本文发展了一整套单探头压力接触法高温钢坯缩孔超声检测实验系统。这个系统可分别用于1120℃钢坯缩孔的超声检测及1300℃以下试块的声速测试等。文中阐述了系统的设计原理,检测与信号处理专用硬件,软件。分析讨论了回波幅度与压力的关系,给出了关系曲线和关系式以及缩孔的检测结果。