How can you use non-destructive testing to evaluate materials?

NDT is useful because it doesn't require destroying the sample to determine the desired characteristic. Some traditional methods are: visual inspection for surface defects; X-ray (for welds); ultrasonic testing (measuring thickness of sheetmetal, or searching for defects embedded in a forging, for example); durometer testing for polymer hardness; and indentation testing of metals for hardness. Although indentation testing leaves a mark, it can be classified as NDT if done in a specific area where the indent doesn't affect the form, fit, or function of the article being tested. Other methods include dimensional measurement (in the case of machined parts); dry film measurement of coatings can be easily measured depending on the substrate.

One way is to build a standard product using known good materials and then build additional devices using new versions of the same materials and test and compare reliability and performance to your standard.

Principle: The simplest form of NDT, visual inspection involves visually examining the surface of a material or component for defects. Application: A preliminary method for detecting surface flaws, corrosion, or other visible issues.

Nondestructive testing (NDT) is a variety of methods used to detect flaws, cracks, or defects in materials or welds without causing damage. Visual inspection is the simplest NDT method, which involves examining the surface and appearance of materials with tools such as magnifiers, cameras, or mirrors.

Using visual inspection as NDT (non destructive test) is simplest method. MSA (Measurement System Analysis) implement to verify and standardize visual inspection. Sensory inspection is common method in food industry. Using x ray inspection is more powerful method although need investment.

? Principle: UT involves the use of high-frequency sound waves that travel through a material. Changes in the wave pattern can indicate defects or inconsistencies in the material. ? Application: Used to detect internal flaws, measure material thickness, and assess bond quality in materials like metals and composites.

We were able to use ultrasonic sound waves for leak testing tanks. It was fast and efficient in detecting weld defects. It can detect discontinuities in the welded material such as crcks, porosity and poor fusion.

Great to use to test welds without having to break them apart. Saves both time and money but requires a learned skill set. Great cost savings initiative.

Common methods include ultrasonic testing, radiography, magnetic particle testing, and eddy current, centric testing. These techniques help identify defects, discontinuities, or material properties, ensuring structural integrity without compromising the material's functionality or structure.

During a supplier Quality Assurance audit, I was very impressed with an in-house audio oscilloscope methodology as a useful QA tool for anyone working with net shape cold formed or cast metal parts. The manufacturer had determined the signal's shape or waveform changed if certain geometries were not present on the part. They developed a process to measure properties of the amplitude or frequency and monitored the sound of parts hitting a bespoke designed metal plate as parts were ejected after a threading process. Upper and lower [sound wave] control limits were established on known good parts. Parts that were not threaded delivered different signals and could be easily isolated for anomaly audits.

Principle: RT uses X-rays or gamma rays to penetrate materials, and the resulting image reveals internal structures and defects. This is quite more efficient and effective for detecting internal defects like cracks, voids, or inclusions in materials such as welds and castings.

X-ray and gamma ray radiography offer advantages in NDT inspections: visualizing internal structures, detecting hidden flaws, analyzing material density and structure, no surface preparation needed, cost-effectiveness, wide range of applications, high accuracy, and ability to inspect assembled components. However, proper safety protocols are essential to mitigate ionizing radiation exposure risks.

In radiographic testing, visual inspection complements the process by allowing inspectors to examine the material's surface for any visible defects or anomalies that may not be fully captured in the radiographic images. Inspectors assess factors like surface irregularities, weld profile, and the presence of cracks, porosity, or other imperfections. This combined approach enhances the overall evaluation of materials for quality assurance in various industries, such as manufacturing and construction.

In radiographic testing, visual inspection complements the process by allowing inspectors to examine the material's surface for any visible defects or anomalies that may not be fully captured in the radiographic images. Inspectors assess factors like surface irregularities, weld profile, and the presence of cracks, porosity, or other imperfections. This combined approach enhances the overall evaluation of materials for quality assurance in various industries, such as manufacturing and construction.

Radiography using x-rays has been used in industry since before the Second World War and the technology has seen significant changes in the last couple of decades. Initially established with x-rays and film, artificial radioisotopes encased in gamma cameras have been introduced as the source of radiation allowing more flexibility on industrial sites. Isotopes such as Cobalt 60, Iridium 192 and more recently Selenium 75 are also used. A shadow image based on material density variations is formed and when used to examine welds defects such as cracks, porosity, and inclusions show up darker than the surrounding metal. Radiation beam orientation must be within about 10o of the crack plane to show cracks.

Principle: MPT is used to detect surface and near-surface flaws in ferrous materials. A magnetic field is applied, and magnetic particles are used to identify irregularities. Application: Commonly employed for inspecting welds, forgings, and other components susceptible to surface defects.

In magnetic particle testing, visual inspection is crucial for evaluating materials. After applying magnetic particles to the surface, a magnetic field is used to detect and highlight defects. During visual inspection, look for indications such as cracks or discontinuities revealed by the accumulated particles. Pay attention to size, shape, and location of indications, as they provide insights into the nature and severity of defects in the material. Consistent lighting and proper training are essential for accurate visual assessment in magnetic particle testing.

Principle: AET involves monitoring the release of acoustic waves during material deformation or damage. Application: Used for monitoring structural integrity, detecting crack growth, and assessing the stability of materials under stress.

In liquid penetrant testing, visual inspection plays a crucial role. After applying the penetrant and developer, carefully examine the surface for indications such as cracks or discontinuities. Look for variations in color or intensity, as these can indicate defects. Proper lighting and thorough observation are key to identifying and evaluating flaws during visual inspection in liquid penetrant testing.

Principle: ECT uses electromagnetic induction to detect changes in conductivity or permeability of a material. Variations can indicate defects. Application: Applied to non-ferrous materials for detecting surface and subsurface cracks, measuring material thickness, and identifying conductivity variations.

Eddy current testing is a non-destructive testing method used to assess materials for defects or inconsistencies. It involves inducing electrical currents in a conductive material and monitoring the resulting eddy currents. Changes in the material, such as cracks or variations in conductivity, affect these currents and can be detected. This method is non-destructive as it doesn't harm the material being tested, making it suitable for quality control and inspection without compromising the integrity of the tested object.

También existe una prueba que no es muy común que sería la de Acid Etch , la cual nos sirve para detectar corrosión o grietas

Friction testing to determine desired sliding properties. Although limited to flat surfaces it is useful in determining tolerances on some specifications. In general used by R&D to benchmark specific coating

Quite new to NDT is CT. Having the ability to view and manipulate the component in 3D has advantages over conventional X-ray. Being able to visualise the faults/porosity and present these to the customer in a way that is easy to see has been a huge step forward in x-ray NDT. Along with advances in Additive manufacturing and the complex shapes being printed, XCT is now a powerful and invaluable tool to the NDT toolkit.

IR Inspection - especially useful in electrical panels. Probably one of the best methods to find problems early before they cause downtime.

Other ways used to do quality inspections for defects or malformations on a manufactured product test device that can measure the clarity of a PET or polyurethane or poly propylene manufactured product. This is very important when you are producing PT for example, parts for grocery store customers bakeries that sell cakes because they want a clear product because visual presentation of the merchandise is very important for sales.