ASNT

acoustic emission testing is also used for in-process weld monitoring, for detecting tool touch and tool wear during automatic machining, for detecting wear and loss of lubrication in rotating equipment, for detecting loose parts and loose particles, for pre-service proof testing, and for detecting and monitoring leaks, cavitation, and f low. Other Methods There are many other methods of nondestructive testing, including optical methods such as hologra- phy, shearography, and moiré imaging; material identification methods such as chemical spot testing, spark testing, and spectroscopy; strain gauging; and acoustic methods such as vibration analysis and tapping.

Acoustic event

Preamplifier

Computer

Test object

Figure 12 Acoustic emission testing setup in which eight sensors permit computer to calculate location of crack propagation.

CHAPTER 1

15

Part 1