Non Destructive Tests
- Spark Optical Emission Spectroscopy
Emission spectrometry is a comparative analytical method in which a small amount of surface material is removed from the specimen. Recent developments in sensors and microelectronics have produced transportable systems that can be used on or adjacent to production lines. In some systems, light from the spark discharge is carried by fiber optics to the sensors, where the wavelengths and intensities of the several spectrum constituents are detected and measured. Photomultipliers are used with diffraction gratings to measure the intensities of preselected analytical lines in the spectrum. The numerical results are displayed in digital form on readouts or printed out in hard copy, or both.
- X-Ray Florescence Method
XRF is an acronym for X-ray fluorescence spectroscopy. XRF is a non-destructive analytical technique used to determine the elemental composition of materials. Handheld XRF analyzers work by measuring the fluorescent (or secondary) X-rays emitted from a sample when excited by a primary X-ray source.
Portable hardness test is a means of determining resistance to penetration (hardness) of a specimen and is occasionally employed to obtain a quick approximation of tensile strength. There are 3 types of portable hardness tests available:
- Vickers
- Rockwell
- Brinell
All tests under this category are conducted on-site by acquiring portable hardness tester equipment.
In-situ Metallography refers to the examination of the microstructure of a metallic component on site. It is typically considered a non-destructive method because the area of interest does not need to be extracted for examination in a lab. However, in practice, In-situ Metallography will require the removal of any paint coatings and the application of light grinding followed by etching before examination can be carried out. Examination of the polished and etched surface can then be carried out immediately by using a portable microscope with attached digital camera or alternatively, by making a replica of the microstructure using special resins or plastics followed by examining the replica in a laboratory.
In-situ Metallography can be used to determine the ferrite to austenite ratio in duplex stainless steel, estimate grain size in carbon and stainless steels as well as examining the general macrostructure and microstructure of a component. It has applications in examination of boilers, heat exchangers and reactors during annual shutdown maintenance, check the effects of post weld heat treatment processes on site, and to verify weld microstructure of very large fracture mechanics (CTOD) specimens prior to notching.