汽车变速器普遍采用焊接齿轮组结构，汽车行驶时变速器齿轮会承受高负荷扭矩并频繁受到冲击，故必须通过无损检测手段来保证齿轮焊缝的质量，目前汽车齿轮焊缝检测的主要方法是脉冲反射法超声检测。探讨了相控阵超声技术用于汽车齿轮焊缝检测的可行性和优越性，对两种齿轮进行了检测试验。试验结果表明，相控阵超声检测技术具有扫查速度快、成像质量好、测量精度高、检测可靠性高等优点。

The welded gear set is widely used in automobile transmission. When the automobile is running, the transmission gear bears high load torque and is frequently impacted. The gear welds must pass the nondestructive testing to ensure their quality. Up to now, the main method of automobile gear weld detection is pulse reflection ultrasonic testing. In this paper, the feasibility and superiority of phased array ultrasonic testing for automobile gears are discussed, and the testing tests for two kinds of gears are carried out. Experimental results show that this method has the advantages of high scanning speed, good imaging quality, high measurement accuracy and high detection reliability.