ASTM E930c Test for Estimating the Largest Grain Observed in a Metallographic Section (ALA Grain Size)

ASTM E930 provides manual procedures for determining the size of the largest grain cross-section observed on a metallographically prepared plane section.

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ASTM E930c Test for Estimating the Largest Grain Observed in a Metallographic Section (ALA Grain Size)

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Overview
Scope, Applications, and Benefits
Test Process
Specifications
Instrumentation

Overview

ASTM E 930 ALA grain size testing is the standardized test method for determining the largest grain size found in the metallographic section of the metal material, which gives a measure of the abnormal grain size of the metal material consisting of austenite grains that are significantly larger than the average grain size of the metal material. ASTM E 930 ALA grain size testing defines the test methods required to identify the largest grain size found in the metal material by specifying the metallographic test procedures and ALA grain size rating necessary to obtain the ALA grain size test results for the metal material.

Scope, Applications, and Benefits

Scope

ASTM E 930 provides an estimation of the maximum grain size of a specimen through an examination of polished and etched specimens of metals under specific magnification conditions. This is done by determining the largest grain size observed from the specimen area and rating it using the ASTM grain size number scale.

ASTM E 930 ALA grain size testing evaluates:

Largest abnormally large austenite grain size in heat-treated metallic material sections
ALA grain size rating of steels, aluminum alloys, and metallic materials requiring grain size control
Comparatively, the largest grain size across heat treatment conditions and processing variables
Effect of austenitizing temperature, time, and cooling rate on abnormal grain growth behavior
Compliance with maximum ALA grain size requirements for metallic material specifications

Applications

Heat-treated steel components requiring ALA grain size verification for mechanical property assurance
Carburized, nitrided, and case-hardened steel components requiring abnormal grain growth assessment
Aerospace and automotive metallic components requiring maximum grain size control verification
Aluminum alloy and non-ferrous metallic materials require the largest grain size characterization
Material suppliers and heat treaters requiring ASTM E 930 ALA grain size test data

Benefits

Provides reliable ALA grain size data for metallic material heat treatment verification
Supports grain size specification compliance and supplier assessment programs
Identifies abnormal grain growth in heat-treated metallic materials before component deployment
Delivers traceable ALA grain size test records for engineering and research submissions
Reduces mechanical property risk by verifying the largest grain size early in heat treatment approval

Test Process

Sample Preparation

Metallic specimens sectioned, mounted, polished, and etched to reveal grain boundaries per ASTM E 930.

Metallographic Examination

Polished sections examined at 100x magnification to identify largest grain across specimen area.

ALA Grain Size Rating

Largest observed grain rated against ASTM grain size number scale per ASTM E 930 procedures.

Data Analysis & Reporting

ALA grain size rating assessed against material specification criteria for test compliance result.

Technical Specifications

Parameter	Details
Applicable Materials	Steels, aluminum alloys, and metallic materials requiring largest grain size characterization
Specimen Preparation	Sectioned, mounted, polished, and etched per ASTM E 3 metallographic preparation requirements
Examination Magnification	100x primary examination magnification per ASTM E 930 grain size rating procedures
Grain Size Scale	ASTM grain size number scale per ASTM E 112 from grain size number 1 to 14
Performance Compliance Benchmarks	ALA grain size number assessed against maximum grain size specification requirements
Measured Outputs	ALA grain size number, largest grain observations, and test compliance result

Instrumentation Used for Testing

Optical metallographic microscope with 100x magnification capability
Specimen preparation equipment, including mounting press, grinder, and polisher
Metallographic etchant system for grain boundary revelation
ASTM grain size comparison chart for ALA grain size number rating
Image analysis system for grain size measurement and documentation
Data reporting and metallographic image capture system

Metallographic examination images showing the largest grain observations across the specimen area
ALA grain size number rating per ASTM E 930 and ASTM E 112 grain size scale
Largest grain size observations and abnormal grain growth assessment data
Test compliance result assessed against the maximum ALA grain size specification requirements
ASTM E 930 ALA grain size test report for material approval, heat treatment verification, and supplier assessment submissions

Why Choose Infinita Lab for ASTM E 930?

Infinita Lab is a trusted USA-based testing laboratory offering ASTM E930 testing services across an extensive network of accredited facilities across the USA. Infinita Lab is built to serve the full spectrum of modern testing needs—across industries, materials, and methodologies. Our advanced equipment and expert professionals deliver highly accurate and prompt test results, helping businesses achieve quality compliance and product reliability.

Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote

Frequently Asked Questions

ASTM E930c includes grain size measurement, magnification level, metallographic preparation, field selection, and largest grain identification, evaluating abnormal grain growth by estimating the largest grain observed in a polished and etched section.

ASTM E930c requires proper metallographic preparation. This includes sectioning, mounting, grinding, polishing, and etching. These steps help to show grain boundaries clearly for the correct identification and measurement of the largest grains present.

ASTM E930c uses optical microscopy at specific magnification to examine metallographic sections. It identifies the largest grain, usually reported with grain size numbers or equivalent diameter measurements.

ASTM E930c is commonly applied to metals and alloys used in aerospace, automotive, and industrial applications where abnormal grain growth can affect mechanical properties and performance.

ASTM E930c depends on visual observation. It can be affected by sample preparation, etching quality, and the judgment of the operator. This means careful analysis is necessary to achieve consistent and reliable results in grain size estimation.