Reasonable process design and ultrasonic testing of high chromium white iron castings

- Jan 25, 2019-

Ultrasonic detection of high chromium white iron castings can also be directly used to check their internal defects when in use. When in use, the sound beam with high frequency sound energy is mainly used to propagate inside the castings and produce reflection when it encounters the internal surface or defects and finds the defects.The magnitude of reflected sound energy is a function of the directivity and nature of the inner surface or defect and the acoustic impedance of such a reflector. Therefore, various defects or reflected sound energy on the inner surface can be applied to detect the location of defects, wall thickness or the depth of defects under the surface.


Ultrasonic testing of high chromium white iron castings is widely used as a non-destructive testing method. Its main advantages are as follows: high detection sensitivity, small cracks can be detected, large penetration ability, and thick section of castings can be detected.The main limitation is that it is difficult to explain the reflection waveform of the disconnection defect with complex profile size and poor directivity.Undesirable internal structures, such as grain size, microstructure, porosity, inclusion content, or fine dispersed precipitates, also interfere with waveform interpretation.


The reasonable process design of high chromium white iron casting, its inner runner will be located in the machine tool casting relative to the thin wall, the number of more and scattered, in the operation of the first into its wall thickness of the metal liquid take the lead in solidification, thin wall after solidification, so that the basic balance of everywhere solidification.For machine tool castings with uniform wall thickness, multiple internal gates and air holes are used.Multiple internal runner, dispersion and uniform distribution, so that the overall heat balance.The air hole is thin and many, namely the exhaust gas is unobstructed also plays the heat dissipation