Macroscopic Examination

Macroetch, Grain Flow, Surface Condition & More

Macro-etchMacroscopic Examination, also called Macro Test or Macro Examination, evaluates the quality and consistency of a test sample using only low or no magnification. Macro examination of metals can be used to assess quality through the evaluation of a sample’s macrostructural features, which may include grain flow, porosity and cracks.

The metallurgical engineering team at Laboratory Testing Inc., near Philadelphia, PA (USA), offers the following macroscopic examination services:

LTI Capabilities

  • Macroetching (ASTM E340)
  • Grain Flow
  • Weld Qualification
  • Surface Condition
  • Surface Finish
  • Digital Imaging

The macro sample is prepared at LTI and generally entails cutting, grinding, polishing and etching. During macroscopic examination, findings can be documented with digital imaging to provide customers with a visual image in the Certified Test Report or a digital file that can be emailed.


  • ASME Sect. IX
  • ASTM E340
  • ASTM E381
  • MIL Specifications

Macro examination of specimens exposed to passivation, salt spray, case depth and other testing, as well as macroscopic examination of welds are frequently performed. A weld cross section examination will reveal internal discontinuities, weld profile, extent of penetration and more. The macrostructural properties of a weldament can be important in weld procedure qualification or welder qualification.

Contact us to discuss your material and requirements.

The Test Process

Before macroscopic examination begins, the test sample must be prepared to specification. Often etching is required after the sample has been cut, ground and polished. Etching is a chemical reaction on the surface of the test sample that allows viewing of the flow properties of the material. The samples can be ingots, castings, plates, bars, sheets or finished products.

The macro examination is performed on the cross section, longitudinal section or through the thickness (‘Z’ direction) of the test sample. The sample is viewed with the unaided eye or at low magnification, usually no greater than 10 times.

Macroetch test to ASTM E340 is the controlled surface etching of a metal or alloy sample to reveal a structure such as grain flow lines and ingot patterns that are visible at the low magnification. Grain flow lines are the resulting fiber pattern observed in a hot or cold worked material, showing the manner in which the metal flowed during the forming process.

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Customer Testimonials

“I wanted to say thank you to the LTI Team for all the support they have provided in our source inspections, as well as on expedited projects. It is nice to work with a group that not only has technical knowledge, but cares about getting the job done right the first time. I know I can count on the LTI team to help me in many situations. N.G.K. Metals looks forward to many more years of working with you.”

David Britt,
N.G.K. Metals Corp.


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