Metal Technology Co. Ltd.





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

Inspection Method

What method is used to look at the stresses in a joint?

We verify the product from test pieces with the same history as the product using tensile and shear tests and other testing methods according to the application.

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 the test method.

In brazing and soldering, the interface with the base metal is alloyed to form a compound layer. Can EPMA determine the bonding status?

The characteristic X-ray detection area is several micrometers, and although it is possible to narrow the area by suppressing irradiation conditions, it is difficult to obtain a completely segmented result because of mutual interference information in the reaction layer in the smallest part. If the cross-section observation result is below the resolution, the pass / fail criteria that meet the requirements other than EPMA are first set, such as combining the results of the strength test.

A product that breaks at the bonding surface and a product that breaks the base material near the bond are both considered to be broken, how do you deal with this case?

In fracture, we consider a base metal fracture to be good, but pass/fail is based on thresholds (stress, ductility, etc.) It depends on the customer's requirements, such as behavior due to cracking, etc. in the S-S curve diagram, or whether it reaches the plastic region above 0.2%.

What is the best method for evaluating the bonding of porous and dissimilar metals?

Evaluation methods vary depending on the requirements and purpose of the bond. If strength is required, it is appropriate to pre-establish appropriate conditions in terms of deformation, bond strength, ductility, and other physical properties, and to manage the evaluation by controlling the process.

Residual stresses occur on the bonded surfaces, but how do you check the stress distribution?

Verification by analysis is carried out in advance. Ex-post testing is verified by XRD, etc. Confirmation is performed when necessary for condition study.

Other than X-ray CT, what other inspections are performed on specimens produced by metal Additive Manufacturing?

In addition to 3D measurement, we can also perform composition analysis and physical property evaluation using test pieces, depending on requirements. For processing including machining, non-destructive testing may also be considered, so please contact us.


Have there been any cases of damage to items that have passed inspection and testing?

There have been no cases of damage in products that have been used within the required range and for which inspection methods have been established, and for which all tests have yielded acceptable results.

Do you have experience with fatigue strength testing in brazing?

Fatigue strength testing of brazed joints is not performed using our equipment, but we can perform such testing under certain conditions. We will also consider and propose joining methods depending on the application and other factors. Please consult with us.

When using an Xray-CT system, how thick can defects be detected in steel materials?

It depends largely on the device's capacity (output) and geometry. It also depends on the required resolution. Please contact us for more details.

Quality Control

Which inspection method is used for mass production inspection of bonded products: full inspection or spot checks?

The requirement determines whether the inspection is a 100% inspection or a spot check. If not specified, the number of sampling will be performed in accordance with official standards.

When inspecting bonded products, are there cases where process assurance would apply?

Control in charts such as treatment conditions (temperature, atmosphere, pressure) of the furnace used in the joining process. In some cases, we also apply inspection methods using stoppieces, etc. These are determined by requirements and consultation.

Do you use destructive testing during production to confirm the results?

This test is performed upon request from the customer. Please let us know when you decide on a contract.

What kind of equipment do you use for leak testing to evaluate airtightness?

In addition to confirming minute leaks with a helium leak detector, we also conduct pressure resistance tests.

Compact electron beam irradiation device

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Document download

  • 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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