|Metallography Subcommittee Approves Extensive Inclusion Content Standard Revision
ASTM International Committee E04 on Metallography has concluded an extensive revision of an important standard, E 45, Test Methods for Determining the Inclusion Content of Steel. Because of this revision, manual and automated image analysis (IA) test methods for obtaining JK nonmetallic inclusion ratings for steel are now defined within one document.
The new version of the standard, which was approved in November 2005, incorporates large elements of another standard, E 1122, Practice for Obtaining JK Inclusion Ratings Using Automatic Image Analysis. Since the approval of the revised E 45, E 1122 has been withdrawn. Both standards are under the jurisdiction of Subcommittee E04.09 on Inclusions.
In order to facilitate the use of the more sophisticated automated inclusion ratings methods, an effort was initiated to combine the two procedures in an extensive revision of Test Methods E 45. A comparison of the revised E 45 to previous versions reveals the following improvements:
• The most important change was incorporating the E 1122 IA procedures into methods A and D of ASTM E 45.
• The aspect ratio of globular oxides was changed from ≤5:1 to ≤2:1.
The rationale for this change was that globular oxides are defined as nondeformable and therefore spherical and the fact that D type inclusions on Plate Ir are never shown exceeding an aspect ratio of 1.8.
In the macroscopic methods, the magnetic particle section has been reduced by eliminating the detailed procedure and simply referring to the appropriate magnetic particle methods such as ASTM E 1444, Practice for Magnetic Particle Testing; E 709, Guide for Magnetic Particle Examination; and the following Society of Automotive Engineers aerospace material specifications: AMS 2300, Premium Aircraft-Quality Steel Cleanliness: Magnetic Particle Inspection Procedure; AMS 2301, Aircraft Quality Steel Cleanliness: Magnetic Particle Inspection Procedure; AMS 2303, Aircraft Quality Steel Cleanliness: Martensitic Corrosion-Resistant Steels Magnetic Particle Inspection Procedure; and AMS 2304, Special Aircraft-Quality Steel Cleanliness: Magnetic Particle Inspection Procedure.
Future improvements to E 45 might include IA techniques from methods B, C and E. Committee E04 welcomes all parties who are interested in participating in future revisions of Test Methods E 45.
With the approval of this latest revision of E 45 and the withdrawal of E 1122, metallographic labs now have the freedom to utilize current technology when rating nonmetallic inclusions in steel. //
Technical Information: John Chir, Timken Latrobe Steel, Latrobe, Pa.
ASTM Staff: Diane Rehiel
November Committee Week