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ASTM E methods for grain counting using microscope reticle. cited ASTM standards, is concerned with the measurement of grain size when the grains are . What is ASTM E standard, and why is this of importance? Number”. Therefore, an image with very small size grains will have more boundaries, resulting in. Using ASTM E as our accredited test specification, and an optical microscope , we can determine the average grain size in various metallic materials.

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Most metals are crystalline in nature and contain internal boundaries, commonly known as “grain boundaries”. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.

Also, choosing a camera that can e12 a fast refresh-rate in live mode will help when focusing or positioning the sample. In addition to analyzing these grains size and distribution trends, rigorous internal quality-control procedures may require that these results be well documented and rgain for future reference.

Grain Size Examination – ASTM E Grain Size Analysis | SGS MSi Testing

How can a metallurgical quality-control laboratory implement a turn-key, fully-automated grains analysis solution, eliminating potential inaccuracies and subjectivity introduced by the human factor, while complying with ASTM E or other international standards?

In many instances, overall accuracy and repeatability, as well as reproducibility has shown improvement. The precision of the method is a function of the number of intercepts or intersections counted. Sorry, this page is not available in your country. A manual or motorized XY scanning stage is required to manipulate the sample and position at the area of interest for observation and analysis.

Equivalent inch-pound values, when listed, are in parentheses and may be approximate.

ASTM E112 Grain Size Examination

Application to Special Situations. Unlike former techniques where operators performed a visual estimation of the grain size, or “G-Number” manually by eye, modern material-science microscope specific image-analysis software allows the grain size to be calculated accurately and repeatedly, as human intervention asrm minimized. Aerospace component manufactures need to pay strict attention to the grains characteristics of an aluminum component used in the landing gear of a commercial aircraft.


When considering a digital camera for Grains analysis, more important than digital resolution is the pixel size, or resulting pixel density. Image of Grains in Steel at x Magnification.

For example, because human life may be at stake, automotive manufactures study the size and distribution of grains in a particular alloy to determine if a newly designed automotive component will hold up under extreme circumstances.

Grain analysis via the Planimetric method. Because an accurate count can be made without need of marking off intercepts or intersections, the intercept method is faster than the planimetric method for the same level of precision. Since the grain size is being estimated by the operator, these methodologies can produce inaccurate and unrepeatable results, often not reproducible between different operators.

This means that the actual, calibrated pixel size must be smaller than nm providing the required 3 pixels per smallest distinguishable feature. Many software packages are designed to comply with ASTM E and a wide-range of international standards, and can be implemented with minimal efforts.

Grain Size Analysis in Metals and Alloys

In former times, and even still in practice today, most quality-control laboratories would analyze grains via the “Chart Comparison” method. The precision of the method is a function of the number of grains counted. Sorry, this page is not available in your country Let us know what you’re looking for by filling out the form below.

This site uses cookies to enhance performance, analyze traffic, and for ads aastm purposes. The test methods may also be used for aize structures having appearances similar to those of the metallic structures shown in the comparison charts. Each time the overlaid pattern intercepts with a grain boundary, an intercept is drawn on the image and recorded hence the name “Intercept Method”.

A PC meeting the minimum system requirements of the camera and image-analysis software, and high-resolution monitor are required. For higher degrees of accuracy in determining average grain size, the intercept sizze planimetric procedures may be used.


Because they show a distribution of grain dimensions, ranging from very e112 to very large, depending on the relationship of the planar section and the three-dimensional array of grains, the charts are not applicable to measurement ast, individual grains. At the time of purchase, the user should determine if the Intercept or Planimetric method is more appropriate.

With accessories including a coded revolving nosepiece and software, the microscope’s modular design makes it easy to customize for your requirements.

Although this may sound confusing, a general rule of thumb is that most common material-science microscopy specific cameras 3MP or greater considering the pixel asttm of most common CCD and CMOS sensors are recommended for Grains analysis. Fracture Grain Size Method. Example of a microscope eyepiece reticle used to compare against a live image.

Results of Interlaboratory Grain Size Determinations. Or, instead of comparing to a micrograph poster, one can insert an eyepiece reticle containing images satm predefined grain size patterns, directly into the microscope’s optical path.

Partially recrystallized wrought alloys and lightly to moderately cold-worked material may be considered as consisting of non-equiaxed grains, if a grain size measurement is necessary. A typical equipment configuration for analyzing grains via digital image-analysis consists of: Enter the modern digital metallurgical QC laboratory. Since the results are calculated internally within the image-analysis software, the guesswork attributed to the human element is removed.

What’s more, many metallurgical-specific microscope image-analysis software packages can be configured to archive the grains results automatically into a spreadsheet or optional integrated database.

When considering a turn-key solution for automatic grains analysis, working directly with an experienced material-science specific microscope manufacturer is of utmost importance, as they can assist you in every step of this process, from equipment selection to full deployment.

The intercept procedure is particularly useful for structures consisting of elongated grains see Section