Nondestructive detection of cold flakes in aluminum alloy die-cast plate with ultrasonic measurement
Nondestructive detection of cold flakes in aluminum alloy die-cast plate with ultrasonic measurement
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DOI：
10.2320/matertrans.45.2403
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发表时间：
2004-07-01
影响因子：
1.2
通讯作者：
Kageyama, K
中科院分区：
文献类型：
--
作者：
Kato, H;Suzuki, T;Kageyama, K
对铝合金压铸件（ADC 12）进行超声波测量，获得超声波强度分布与板中出现的冷屑位置之间的关系，以开发一种无损检测压铸件中冷屑的方法。生产长170 mm、宽50 mm和厚6.8 mm的压铸板，其具有更宽的浇口以在板中引入更大的冷薄片。然后，通过使用产生频率为20 MHz的纵波的探头，用浸入法进行超声波测量。得到了超声波从表面到底部的强度分布。通过截面分析，考察了冷片的分布情况。从截面分析中观察到三种类型的冷片：A型，初始凝固时边界平直，有氧化薄层; B型，边界平直，无氧化层; C型，边界不规则，呈波浪形，无氧化层。在C型的情况下，氧化层被认为是在观察到的部分之外。超声波在冷片与基体之间的前后边界处有轻微的反射，通过超声波测量可以检测出冷片的位置和厚度。
Aluminum alloy die-cast plates (ADC 12) were subjected to ultrasonic measurement to obtain a relation between the intensity distribution of the ultrasonic wave and positions of cold flakes appearing in the plate for developing a nondestructive method to detect cold flakes in the die-casts. Die-cast plates of 170 mm in length, 50 mm in width and 6.8 mm in thickness were produced with wider gates to introduce larger cold flakes in the plate. Then the ultrasonic measurement was carried out with the immersion method by using a probe generating a longitudinal wave of 20 MHz in frequency. Intensity distributions of the ultrasonic wave were obtained from the surface to the bottom. The cross section analysis was carried out to examine the distribution of the cold flake. From the cross section analysis, three types of cold flakes were observed: the type A with a straight boundary of initial solidification with oxide thin layer, the type B with a straight boundary without oxide layer, and the type C of an irregular and wavy boundary without oxide layer. In the case of the type C, the oxide layer was thought to be out of the observed section. The ultrasonic wave was slightly reflected from the front and rear boundaries between the cold flake and the matrix, and it was found that the position and the thickness of the cold flake can be detected by ultrasonic measurement.