Detection of cracks and bonding defects
in disk brake linings.
盘式制动衬片的粘接和裂纹缺陷的检测

In our Application Reports 06/97 and 07/97, we reported on ultrasonic testing of brake linings and of bonded joints in brake bodies.
在应用报告06/97 和07/97中，我们讲述了在制动体中粘接接头和制动衬片的超声检测
The present case deals with testing of brake bodies, consisting of a steel base plate, a welded-on grid mat as bonding agent and the sinter-fused braking substance (friction lining),
下图展示一个焊接上的网格垫作为粘接剂，钢基体和烧结熔融的制动物质组成的制动体检测。

SOLUTION:方案                                   
The present brake lining structure with its extremely high sound absorption and scattering calls for the through-transmission technique using a test frequency of 100 kHz. We recommend the use of the probes type B 0,1 NN for this application case. This probe type enables a dry and point-to-point coupling.
由于制动衬片结构具有很高的声吸收和散射，因此需要频率为100khz的穿透法技术，推荐使用B0型1 NN 探头，这种探头类型能够实现干式和点对点耦合。
In order to ensure uniform coupling conditions, it is necessary to have a device enabling to reach a pressure force of ~100 N.

为了确保耦合的均匀，需要一个能够达到100N压力的设备

In the case of cracks and bonding defects, a low through-transmission amplitude is obtained due to the reduced acoustic transmittance. On the other hand, a high sound amplitude indicates a flaw-free area.
有裂纹和粘接缺陷的存在情况下，由于降低了声能的穿透性能，穿透技术得到的波幅会很低，另一方面，在没有缺陷的区域穿透技术得到的声波波幅会很高。

The following figure is an example of the distribution of the through-transmission amplitude (in % screen height) over the lining surface, obtained by point scanning.
下图是通过点扫，在衬面上获得穿透法波幅高度（示波屏高度百分比）分布的举例

SUITABLE EQUIPMENT:
设备

Ultrasonic flaw detectors: USM 22L  USD 10NF
超声仪器
Probe:     B 0,1 NN  (transmitter and receiver)
探头