Metal Technology Co. Ltd.




Non-destructive inspection

These FAQs were answered during the MTC webinar. Please click here for more details.


Is it possible to train people outside the company in NDT?

Training is available for NAS 410 PT, UT and RT. Please contact us for more information.

Is it possible to undertake an external Responsible Level 3 contract?

Yes it is. However, there is a concern that if external accreditation of "RL3", which requires familiarity with all in-house NDTs, is carried out, the commissioning risk may be high due to the wide range of evidence required for RL3 certification. as an outsourcer, the evidence required for RL3 certification may be diverse and the risk of outsourcing may be high.

Is it possible to have NDT only?

Yes it is. Please contact us for more information.

We have requested heat treatment and machining services, but can we also request NDT in addition?

Yes. This will reduce delays in outsourcing.It is no problem. Please consider this as a way of reducing saw-shape outsourcing, which is a problem in many areas.

Are there any restrictions on the size, shape or material of the product to be NDT tested?

The inspection method may limit the size, shape, material and detectable defects of the test part. Please contact us for more information.

What is the turnaround time if only NDT is requested?

The shortest is three days.

Is it possible to issue a quality certificate for NDT?

It is possible to issue a certificate in the form of JIS Q 9100.

What form will the test results be provided in?

We will provide you with a quality assurance letter + any other documents you request.

Is it possible to carry out on-site inspections at other companies or bring products to MTC for inspection?

Yes it is. Please contact us for more information.


What is the difference between surface defects and defects just below the surface?

The classification of non-destructive testing includes (1) surface, (2) just below the surface, and (3) interior, with (1) being cracks connected to the surface. The same internal defects are classified as (2) and (3), but (2) indicates defects located in the area close to the surface where the closed part cannot be confirmed from the surface by a test method.

What is the penetration depth of Ultrasonic Testing (UT)?

The higher the frequency of the probe, the thinner the wall can be inspected. Depending on the material, for example, 20 Mhz will result in a thickness of about 0.2 mm, while 5 Mhz will result in a thickness of about 30 cm.

In Magnetic particle Testing (MT), when circular magnetisation is followed by longitudinal magnetisation, is it always necessary to demagnetise between each magnetisation?

Depending on the manufacturer's manual for the test object, demagnetisation between each magnetisation is recommended. If not demagnetising after circular magnetisation could affect the inspection decision after longitudinal magnetisation.

What is the minimum size of flaws that can be detected by Magnetic particle Testing (MT)?

The minimum detectable size of flaws is approximately 0.1-0.25 mm.

When Penetrant Testing (PT) is carried out on parts that are to be passivated, is the inspection usually carried out before or after the passivation process?

If the objective is to do a final check, it is fine to do it after the treatment. On the other hand, if the soundness of the treatment needs to be monitored, it would be better to carry this out before and after.

Are there differences in the visibility of monocrystalline and polycrystalline metals in NDT?

The direction of crystals may be visible on Radiological Testing (RT).

What is the maximum dimension of the inspection body that can be subjected to Eddy current Testing (ET)?

It can be carried out manually and has no dimensional limitations. The inspection range and inspection time are proportional.

Can NDT detect cracks as small as 0.5 mm?

It is possible. The inspection method is selected according to the material and the location of the defect.

Is it possible to carry out Magnetic particle testing (MT) and Penetrant Testing (PT) of areas that are inaccessible to the human eye, such as tubular inner surfaces?

It is physically impossible to PT or MT into areas that cannot be reached by the eye, so if inspection using a camera is required, the regulations will be followed. However, the use of cameras requires special skills and management. You may wish to try Radiological Testing (RT).

Are film or digital results easier to see in X-ray testing?

Although it is difficult to say, advances in digital technology have made it possible to detect defects as small as 0.25 mm. The advantage of digital technology is that defects can be magnified by a factor of up to four, making them easily visible to everyone and enabling inspection results to be checked anywhere in the world.


How much does it cost to commission a NDT?

It costs around 50,000 yen, depending on the test.


What is the difference between ASNT and NAS?

ASNT (The American Society for Nondestructive Testing), equivalent to JSNDI (Japan Society for Non-Destructive Inspection) in Japan; National Aerospace Standard (NAS) (publicly known standard). 

Compact electron beam irradiation device

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  • Company information
  • Technology information (Japanese)
  • Technology information (English)
  • HIP unit list
  • Hot press equipment list
  • Possible material combinations for brazing
  • MICROTRON Test Machine MIC1
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