This document specifies the method and apparatus for: — the measurement of the delta ferrite content, expressed as Ferrite Number (FN), in largely austenitic and duplex ferritic-austenitic stainless steel[1] weld metal through the attractive force between a weld metal sample and a standard permanent magnet; — the preparation and measurement of standard pads for manual metal arc covered electrodes. The general method is also recommended for the ferrite measurement of production welds and for weld metal from other processes, such as gas tungsten arc welding, gas shielded metal arc welding and submerged arc welding (in these cases, the way of producing the pad should be defined); — the calibration of other instruments to measure FN. The method laid down in this document is intended for use on weld metals in the as-welded state and on weld metals after thermal treatments causing complete or partial transformation of ferrite to any non-magnetic phase. Austenitizing thermal treatments which alter the size and shape of the ferrite change the magnetic response of the ferrite. The method is not intended for measurement of the ferrite content of cast, forged or wrought austenitic or duplex ferritic-austenitic steel samples.
[1] The term "austenitic-ferritic (duplex) stainless steel" is sometimes applied in place of "duplex ferritic-austenitic stainless steel".
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Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Calibration
5.1 Coating thickness standards
5.2 Magnet
5.3 Instruments
5.4 Calibration curve
6 Standard method for covered electrode test pads
6.1 Dimensions of weld metal test specimens
6.2 Depositing weld metal test specimens
6.3 Measuring
7 Standard methods for test pads of other processes and for production welds
7.1 Standard method for test pads for other weld metals
7.2 Production welds
8 Other methods
8.1 Methods
8.2 Maintaining calibration
9 Procedures used to prepare secondary standards for delta ferrite in austenitic stainless steel weld metal
Annex A Manufacture of secondary standards by strip cladding (informative)
Annex B Manufacture of secondary standards by centrifugal chill casting (informative)