The experiment also studied the effect of the original […]
The experiment also studied the effect of the original beta grain size on the level of ultrasonic flaw detection. Two kinds of test blocks with different original β grain sizes were obtained by heat treatment at different temperatures above the phase transition point. The two heat treatment regimes were: (1) 1300 ° C / 1 h, FC; (2) 1000 ° C / 1 h, FC . After the heat treatment and descaling, the test piece has a super-final size of Φ120 mm×20 mm, and then ultrasonic testing is performed on the test pieces with different grain sizes. test results:
(1) The denser the distribution of the microstructure unevenness of the test block, the higher the detection clutter, and the crystal orientation of the adjacent uneven zone is different.
(2) Since the size of the uneven region is larger than the lower limit of the ultrasonic detection limit, and the elastic properties of the adjacent uneven regions are different (such as the difference in crystal orientation), the sound velocity and the acoustic impedance are different on both sides of the interface of the uneven region, resulting in the occurrence of ultrasonic waves at the interface. Reflection, generating clutter.
(3) The test piece of the same thickness has a smaller interface than the alloy of the coarse original β grain (such as the β grain boundary and the α crystal group interface), and the number of times the ultrasonic wave is reflected to generate the clutter is less, and the generated clutter is generated. The level is lower than the test piece with the smaller original β grains.