AWS A4.2M:2020 pdf download.Standard Procedures for Calibrating Magnetic Instruments to Measure the Delta Ferrite Content of Austenitic and Duplex Ferritic-Austenitic Stainless Steel Weld Metal
1. Scope
1.1 AWS A4.2M specifies the method and apparatus for
• the measurement of the delta ferrite content, expressed as Fenite Number (FN). in largely austenhtie and duplex ferriticaustenitic stainless steel’ weld metal through the attractive force between a weld metal sample and a standard permanent magnet;
• the preparation and measurement of standard pads for shielded 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 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 described in this standard 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 will change the magnetic response of the ferrite.
The method is not intended for measurement of the ferrite content of cast, forged or wrought austenhtic or duplex ferriticaustenitic steel samples.
1.2 Safety and health issues and concerns arc beyond the scope of this standard: sonic safety and health information is provided, but such issues are not fully addressed herein. Safety and health information is available from the following sources:
American Welding Society:
(1) ANSI Z49. I, Safely iii Welding. Culling. and Allied Processes
(2) AWS Safety and Health Fact Sheets
(3) Other safety and health information on the AWS wehshe
Material or Equipment Manufacturers:
(1) Safety Data Sheets supplied by materials manufacturers
(2) Operating Manuals supplied by equipment manufacturers Applicable Regulatory Agencies
Work pertormed in accordance with this standard may involve the use of materials that have been deemed hazardous and may involve operations or equipment that may cause injury or death. This standard does not purport to address all safety and health risks that may be encountered. The user of this standard should establish an appropriate safety program to address such risks as well as to meet applicable regulatory requirements. ANSI Z49. I should be considered when developing the safety program.
3. Principle
The measurement of the ferrite content of largely austenitic stainless steel weld metal through the attractive force between a weld metal sample and a permanent magnet is based upon the fact that the attractive force between a two-phase (or multiphase) sample containing one ferromagnetic phase and one (or more) non-ferromagnetic phase(s) increases as the content of the ferromagnetic phase increases. In largely austenitic and duplex ferritic-austenitic stainless steel weld metal, ferrite is ferromagnetic, whereas austenite, carbides, sigma phase, and inclusions are non-ferromagnetic.AWS A4.2M pdf download.