A Brief History of Non-Destructive Testing

A Brief History of Non-Destructive Testing

Although history does not provide a precise starting date for non-destructive testing, its use dates back many, many years.

It is said that that flour and oil were used during Roman times to find cracks in marble slabs. For centuries, blacksmiths used sonic NDT when listening to the ring of different metals as they were being hammered into shape; a technique also used by early bell makers.

One of the first recorded uses of NDT was in 1868, when Englishman S.H. Saxby relied on the magnetic characteristics of a compass to find cracks in gun barrels.

X-Ray Testing

The first NDT method to come into industrial application was the X-Ray technique.

In 1895, German physicist Wilhelm Conrad Röntgen’s experiments with cathode rays led him to discover X-rays, an invention that earned him the first-ever Nobel Prize. In his first publication on the topic, Röntgen described various uses including possible flaw detection.

The industry did not need the invention at the time, but the medicine did, so medical equipment was the first to be developed. It wasn’t until 1930 that the industrial use of X-ray technology came into being when Richard Seifert developed higher energy medical equipment expanding its use with other application through cooperation with welding institutes.

Magnetic Particle Testing (MPT)

Magnetic particle crack detection was executed even earlier than X-ray testing. We already mentioned the Englishman S. M. Saxby, but, in 1917, an American by the name of William Hoke also tried to find cracks in gun barrels by magnetic indications.

Real industrial application came in 1929 by Alfred Victor de Forest and Foster Baird Doane, who, in 1934, formed the company Magnaflux to manufacture NDT products like those sold on our website.

Liquid Penetrant Testing (LPT)

According to Inspectioneering.com, one of the first methods of NDT was an early form of liquid penetrant testing called the “Oil and Whiting Method,” which came into use in the second half of the 19th century.

Primarily used by the railroad industry, early inspectors relied on this method to increase the “see ability” of defects not typically seen visually.

Ultrasonic Testing (UT)

Ultrasonic testing was the latest NDT technique to come into industrial use.

In 1847, methods of “exciting” ultrasound were discovered by James Prescott Joule and then later in 1880 by Pierre Curie and his brother Paul Jacques.

The first “industrial” application was recommended following the tragic sinking of the Titanic, and, in 1929, a Russian named Sokolov proposed the use of ultrasound for testing castings.

NDT Following World War II

NDT began to be recognized as an independent technology during WWII, partly through the founding of The American Industrial Radium and X-ray Society in 1941 – known today as ASNT.

The uses of visual aids such as mirrors, telescopes, and rigid borescopes (at times referred to as endoscopes), as well as other measuring devices, expanded into other industrial fields.

Water-washable penetrants and “wet” developers originated during WWII and were refined well into the 1950s.

The benefits of MPT were realized during the war, and in the years following, significant developments and refinements contributed to its increased use and expanded applications.

Radiographic testing also saw meaningful innovation after the war, as did the use of UT.


NDT has come a long way since the early years, and those of us involved in the industry today owe a debt of gratitude to these pioneers, many of whom never lived to see the fruit of their labor. Had it not been for their efforts, non-destructive testing as an industry might not even exist.