小口径薄壁管超声检测系统中发射接收电路的设计与实现

Design and Realization of Transmitting and Receiving Circuit of Ultrasonic Detection System for Tubes with Small Diameter and Thin Wall

针对小口径薄壁管曲率大、缺陷小、回波幅度小、衰减大等问题设计了一种超声发射接收电路。主要包括两个方面:一方面设计优良的发射电路以最有效的方式激励超声探头;另一方面设计具有较低噪声的接收电路。所设计的发射电路能够产生幅度-120 V、前沿时间8 ns的高压激励脉冲;接收电路的增益可调范围为80 dB。将研制的发射接收电路应用于超声检测系统中,并进行试验研究,检测试样为钛合金管,最小尺寸为φ6 mm×0.5 mm,样管上的最小人工缺陷尺寸为0.05 mm×0.11 mm×2.9 mm的内伤,试验结果表明,所设计的超声发射接收电路具有足够高的信噪比来对小尺寸钛合金管进行实时检测。

A transmitting and receiving circuit was presented and developed for ultrasonic detection for tubes with small diameter and thin wall. Detecting for this kind of tubes usually encounters the difficulty of large curvature, small defects and small echo amplitude. The transmitting and receiving circuit is realized from two aspects. One is designing good transmitting circuit to excite the ultrasonic probe effectively. The other is designing good receiving circuit with low noise. The transmitting circuit can transmit high voltage pulse with the leading edge transition duration of 8 ns and the amplitude of -120 V. The range of the gain change of the receiving circuit can reach 80 dB. The experiments have been conducted by the transmitting and receiving circuit for detecting the titanium alloy tubes with different size. The minimum diameter and wall thickness of the tubes are 6 mm and 0. 5 mm respectively. The artificial defects are fabricated in the tubes. The minimum defect is on the inner surface of the tube and the size is 0. 05 mm（depth） × 0. 11 mm（width） × 2.9 mm（length）. The experiment results show that the transmitting and receiving circuit is well performed at the detection for the tubes with small diameter and thin wall.