Nondestructive testing (NDT) examines materials and parts without damaging them, so they can go on to do their job. It works mostly out of sight, in almost every industry that builds or runs anything that matters. This series explains, in plain English, where it is used and why.
Each article covers what can fail, which methods are used and on what, how inspection fits into manufacturing and maintenance, the codes and standards you are likely to meet, and what it all means for buyers and owners.
Spot welds, castings, forgings, battery packs and leak-tight systems — how inspection keeps high-volume production safe without slowing the line.
Read article →Structural steel welds, bolted connections, concrete and bridges — how inspection confirms that what was built matches what was designed.
Read article →Hygienic welds, pressure vessels, clean utilities and container closure integrity — where inspection supports product quality and GMP.
Read article →Launch vehicles, pressure vessels, composites and 3D-printed engine parts — why spaceflight hardware gets some of the most demanding inspection anywhere.
Read article →Engine disks, forgings, castings and composites — how aerospace suppliers inspect parts, qualify inspectors under NAS410 and stay Nadcap-accredited.
Read article →Fatigue cracks, hidden corrosion and composite damage — how airlines, repair stations and operators use inspection to keep aircraft flying safely for decades.
Read article →Robots that perform inspections, and robots that need inspecting — why automation changes how NDT is done but not what it has to prove.
Read article →Hygienic welds, heat exchangers, retorts, refrigeration systems and sealed packages — where inspection protects consumers and keeps plants running.
Read article →Hull welds, thickness gauging, shafting and piping — how inspection supports classification surveys, naval requirements and a ship's long working life.
Read article →Military aircraft, vehicles, ships and munitions — how inspection supports readiness, and what makes defense NDT programs different from commercial ones.
Read article →Roller coasters, spinning rides and water slides — how inspection finds fatigue cracks in axles, welds and pins before riders ever notice anything.
Read article →Who performs the eddy current, who signs the logbook — how A&P mechanics and IAs work with NDT in annuals, 100-hours and airworthiness directives.
Read article →From the wellhead to the refinery gate: what inspection looks for across the oil and gas value chain, and how the rules change from one segment to the next.
Read article →Sulfidation, hydrogen attack, corrosion under insulation and the turnaround crunch: how refineries use inspection programs, RBI and fitness-for-service to keep hot, hazardous units running.
Read article →Drill pipe that bends a million times, casing that must hold a well for decades, and platforms standing in seawater: how inspection keeps the upstream end of the industry running.
Read article →Girth welds, smart pigs, dig verification and tank floors: how pipeline operators use inspection to build safely and to keep thousands of miles of buried pipe in service.
Read article →Cracking furnaces, hot hydrogen, corrosion hidden under insulation and vibrating small-bore piping: how petrochemical plants find damage before it becomes a release.
Read article →Corrosive chemicals, stainless steel that cracks, plastic and lined equipment, and OSHA's mechanical integrity rule: how chemical plants build inspection programs that hold up.
Read article →The recovery boiler, where a tube leak can mean an explosion; digesters that crack; and pressurized dryer cylinders the size of a room: how mills use inspection to run safely.
Read article →Topic guides that cut across industries: how a technique is chosen, what a certification means, and what the abbreviations stand for.
API 510 vs 570 vs 653, where 1169, 577, 571, 580 and 936 fit, how they compare with a CWI, and how API inspectors and NDT technicians share the work.
Read article →Eddy current, remote field, near field, MFL or IRIS? How to match a tube inspection technique to the tube material and the damage you expect, and why the analyst matters as much as the probe.
Read article →How high-frequency sound finds internal flaws and measures wall thickness, where UT is used, and what it can miss.
Read article →How X-rays and gamma rays show the inside of welds and castings, what film and digital radiography record, and why radiation safety shapes the job.
Read article →How induced electrical currents reveal cracks, corrosion and material differences in conductive metals, and why the method is a staple of aircraft and tube inspection.
Read article →How a magnetic field and iron particles make surface cracks in steel visible, why direction matters, and which materials it cannot test.
Read article →How a dye drawn into surface-breaking cracks is pulled back out so they can be seen, why cleaning decides the result, and what PT cannot find.
Read article →Why looking carefully, with the right light, tools and acceptance criteria, is a real inspection method and usually the first one performed.
Read article →How sensors listen for the tiny bursts of energy a growing flaw releases under load, why AE can watch a whole structure at once, and why it needs follow-up.
Read article →How bubble, pressure change and tracer gas tests show whether something is sealed, how they differ, and why a leak test is not a strength test.
Read article →What Level I, II and III people actually do, how employer-based certification differs from central certification, and how training hours, experience, exams and vision tests fit together.
Read article →Plain-English definitions of the abbreviations you meet in inspection: methods, certifications, standards bodies, integrity programs and more.
Open the glossary →The articles refer to these methods by their usual two-letter names. Each has strengths and limits, and choosing the right one for the part and the defect is most of the job. For more than 180 abbreviations and terms, from PAUT and IRIS to RBI and NAS410, see our NDT Acronyms and Terms glossary.
Looking closely, often with borescopes, cameras and magnifiers. The first and most widely used method.
A dye drawn into surface-breaking cracks, then drawn back out so they show. Works on most non-porous materials.
Magnetizes steel parts so iron particles gather at surface and near-surface cracks.
High-frequency sound finds internal flaws and measures thickness. Phased array (PAUT) adds imaging.
Electrical currents induced in conductive metals reveal cracks, corrosion and material differences.
X-rays or gamma rays show inside a part; CT builds a full 3D picture.
Listens for the tiny bursts of sound a growing flaw releases while a structure is loaded.
Infrared cameras see how heat moves through a part, revealing disbonds, voids and hot spots.
Tell us what you build, buy or maintain and we will help you work out the inspection approach that fits.
NDT LLC is an independent consulting firm and is not affiliated with, endorsed by or sponsored by any standards body, regulator, agency or other organization named in these articles; names are used only for identification. Articles are general information, not engineering, legal or regulatory advice.