AS 2025-1991

1 - AS 2025-1991 METALLIC MATERIALS - ROCKWELL SUPERFICIAL HARDNESS TEST - N AND T SCALES
4 - PREFACE
5 - CONTENTS
6 - SECTION 1 SCOPE AND GENERAL
6 - 1.1 SCOPE
6 - 1.2 REFERENCED DOCUMENTS
6 - 1.3 DEFINITIONS
6 - 1.3.1 Arithmetic mean deviation
6 - 1.3.2 Calibration
6 - 1.3.3 Calibrating authority
6 - 1.3.4 Hardness test blocks
6 - 1.3.5 Indenter, reference
6 - 1.3.6 Indenter, standard
6 - 1.3.7 Standard hardness blocks
6 - 1.3.8 Standardizing authority
6 - 1.3.9 Test piece
6 - 1.3.10 Test specimen
6 - 1.3.11 Normative
7 - 1.4 ROCKWELL TEST PRINCIPLE
7 - 1.5 DESIGNATION OF ROCKWELL SUPERFICIAL HARDNESS
8 - 1.6 HARDNESS CONVERSIONS
9 - SECTION 2 TESTING OF METALS
9 - 2.1 GENERAL
9 - 2.2 TESTING MACHINE
9 - 2.2.1 General
9 - 2.2.2 Installation
9 - 2.2.3 Calibration
9 - 2.3 INDENTERS
9 - 2.4 ANVIL
9 - 2.5 MAINTENANCE OF THE TESTING MACHINE BY THE USER
9 - 2.5.1 General
9 - 2.5.2 Inspection of components and operations
9 - 2.5.3 Performance tests by the user
9 - 2.5.4 Record of user tests
10 - 2.5.5 Assessment of results of user tests
10 - 2.6 TEST PIECE
10 - 2.6.1 Preparation of test piece
10 - 2.6.2 Thickness of test piece
10 - 2.7 TEST PROCEDURE
11 - 2.8 RECORD OF TEST RESULTS
12 - 2.9 TEST REPORT
13 - SECTION 3 COMPLETE CALIBRATION OF THE TESTING MACHINE
13 - 3.1 GENERAL
13 - 3.2 PRELIMINARY INSPECTION
13 - 3.3 CALIBRATION OF APPLIED FORCES
13 - 3.3.1 Calibrating equipment
13 - 3.3.2 Preliminary force (initial setting)
13 - 3.3.3 Preliminary force (after application and removal of the additional force)
14 - 3.3.4 Total force
14 - 3.4 CALIBRATION OF MEASURING APPARATUS
14 - 3.4.1 Scale
14 - 3.4.2 Calibration ranges
14 - 3.4.3 Accuracy
14 - 3.5 VISUAL EXAMINATION OF INDENTERS
14 - 3.5.1 Diamond cone indenter
14 - 3.5.2 Steel ball indenter
14 - 3.6 PERFORMANCE TEST
14 - 3.6.1 Preparation of steel ball indenters prior to the performance test
14 - 3.7 RECORD OF RESULTS
15 - 3.8 REPORT OF COMPLETE CALIBRATION
16 - SECTION 4 PARTIAL CALIBRATION OF THE TESTING MACHINE
16 - 4.1 GENERAL
16 - 4.2 PRELIMINARY INSPECTION
16 - 4.3 INDENTING PROCEDURE
16 - 4.3.1 General
16 - 4.3.2 Calibration procedure
16 - 4.4 ASSESSMENT OF PERFORMANCE
16 - 4.4.1 Acceptance
17 - 4.4.2 Repeatability
17 - 4.4.3 Error
18 - 4.5 RECORD OF RESULTS
18 - 4.6 REPORT OF PARTIAL CALIBRATION
19 - SECTION 5 CALIBRATION OF STANDARD HARDNESS BLOCKS
19 - 5.1 GENERAL
19 - 5.2 REQUIREMENTS FOR STANDARD HARDNESS BLOCKS
19 - 5.3 CALIBRATION OF BLOCKS
19 - 5.3.1 Procedure
19 - 5.3.2 Uniformity of hardness
19 - 5.3.3 Assigned value
19 - 5.3.4 Report
19 - 5.4 STANDARDlZING MACHINE
19 - 5.4.1 General
19 - 5.4.2 Forces
20 - 5.4.3 Reference indenters
20 - 5.4.4 Measuring apparatus
20 - 5.4.5 Application of forces
20 - 5.4.6 Verification of standardizing machine
21 - SECTION 6 CALIBRATION OF STANDARD DIAMOND CONE INDENTERS AND STEEL BALLS
21 - 6.1 GENERAL
21 - 6.2 DIAMOND CONE INDENTER
21 - 6.2.1 Condition
21 - 6.2.2 Dimensions
21 - 6.2.3 Performance
21 - 6.3 STEEL BALL INDENTER
21 - 6.3.1 Sampling for assessment of batch
21 - 6.3.2 Surface condition
21 - 6.3.3 Diameter
21 - 6.3.4 Hardness
22 - APPENDIX A - TESTS ON CURVED SURFACES

Sets out requirements for the measurement of the Rockwell superficial hardness of metals when using the N and T scales, and for the installation, calibration and maintenance of the testing machine. It also specifies requirements for the calibration of standard hardness blocks and diamond cone and steel ball indenters. In this edition the testing and calibration requirements have been combined into one Standard.

This Standard sets out methods for measuring the hardness of metals and metal products using the N and T scales of Rockwell superficial hardness. It includes requirements for the installation and calibration of the testing machine and recommendations for its maintenance by the user. This Standard does not preclude the use of portable hardness testing machines which meet the appropriate requirements of Section 2. This Standard does not meet the requirements of Rockwell scales A to K, as these are dealt with in AS 1815, nor does it cover the testing of materials other than metals.

First published as AS 2025.1-1977.
Revised and redesignated AS 2025-1991.