ARP1820C Chord Method of Evaluating Surface Microstructural Characteristics

Revised

05/19/2021

Features
Issuing Committee
Scope
Content
This practice provides a method for evaluating microhardness and microstructure very close (0.002 inch (0.051 mm) or less) to the surface of a disk specimen. Specific accept/reject criteria for partial decarburization (3.7.1), inadvertent carburization/nitriding (3.7.3), total decarburization/intergranular oxidation (3.8), and other characteristics evaluated are to be found in the applicable specification where this ARP is referenced.
Rationale
Content
ARP1820C results from a Five-Year Review and update of this specification with rewritten Introduction and Scope to add clarity, disc surface texture changed from 32 to 18 as it was more desirable but that higher texture may be needed for smaller diameters (3.1), added ASTM E385 for determining Knoop microhardness and allowed for staggered indentations (3.5), changed hardness for Depth of Decarburization to be consistent with AMS2759 (3.6), added clarifying wording for Inadvertent Carburization and Nitriding (3.7.2), and Figures 2, 3, and 4 were replaced with more accurate figures.
Meta TagsDetails
DOI
https://doi.org/10.4271/ARP1820C
Pages
7
Citation
SAE International Recommended Practice, Chord Method of Evaluating Surface Microstructural Characteristics, SAE Standard ARP1820C, Revised May 2021, Reaffirmed April 2012, Issued October 1984, https://doi.org/10.4271/ARP1820C.
Additional Details
Publisher
Published
May 19, 2021
Product Code
ARP1820C
Content Type
Recommended Practice
Status
Revised
Language
English

Revisions