ASTM A1084-15a(2022)
Standard Test Method for Detecting Detrimental Phases in Lean Duplex Austenitic/Ferritic Stainless Steels

Standard No.

ASTM A1084-15a(2022)

Release Date

2022

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM A1084-15a(2022)

Scope

1.1 The purpose of this test method is to allow detection of the presence of detrimental chromium-containing phases in selected lean duplex stainless steels to the extent that toughness or corrosion resistance is affected significantly. Such phases can form during manufacture and fabrication of lean duplex products. This test method does not necessarily detect losses of toughness nor corrosion resistance attributable to other causes, nor will it identify the exact type of detrimental phases that caused any loss of toughness or corrosion resistance. The test result is a simple pass/fail statement. 1.2 Lean duplex (austenitic-ferritic) stainless steels are typically duplex stainless steels composed of 30 % to 70 % ferrite content with a typical alloy composition having Cr > 17 % and Mo < 1 % and with additions of Nickel, Manganese, Nitrogen and controlled low carbon content as well as other alloying elements. This standard test method applies only to those alloys listed in Table 1. Similar test methods for some higher alloyed duplex stainless steels are described in Test Methods A923, but the procedures described in this standard differ significantly for all three methods from the ones described in Test Methods A923. 1.3 Lean duplex stainless steels are susceptible to the formation of detrimental chromium-containing compounds such as nitrides and carbides and other undesirable phases. Typically this occurs during exposures in the temperature range from approximately 300 °C to 955 °C (570 °F to 1750 ºF) with a maximum susceptibility in the temperature range around 650 °C to 750 °C (1200 °F to 1385 ºF). The speed of these precipitation reactions is a function of composition and the thermal or thermo-mechanical history of each individual piece. The presence of an amount of these phases can be detrimental to toughness and corrosion resistance. 1.4 Because of the low molybdenum content, lean duplex stainless steels only exhibit a minor susceptibility to sigma or other types of molybdenum containing intermetallic phases. Heat treatment, that could lead to formation of small amounts of molybdenum containing intermetallics, would result in a large amount of precipitation of detrimental nitrides or carbides, long before any signs of sigma and similar phases would be observed. 1.5 Correct heat treatment of lean duplex stainless steels can eliminate or reduce the amount and alter the characteristics of these detrimental phases as well as minimizing Cr-depletion in the matrix phase in the immediate vicinity of these phases. Adequately rapid cooling of the product from a suitable annealing temperature provides the maximum resistance to formation of detrimental phases by subsequent thermal exposures. For details of the proper annealing temperature recommendations for the alloy and product in question, the user is referred to the relevant applicable ASTM product specification. 1.6 Compliance with the chemical and mechanical requirements for the applicable product specification does not necessarily indicate the absence of detrimental phases in the product. 1.7 These test methods include the following: 1.7.1 Test Method A—Etch Method for detecting the presence of potentially detrimental phases in Lean Duplex Stainless Steels 1.7.2 Test Method B—Charpy V-notch Impact Test for determining the presence of detrimental phases in Lean Duplex Stainless Steels. 1.7.3 Test Method C—Inhibited Ferric Chloride Corrosion Test for determining the presence of detrimental phases in Lean Duplex Stainless Steels. 1.7.4 Examples of the correlation of thermal exposures, the occurrence of detrimental phases, and the degradation of toughness and corrosion resistance are given in Appendix X2, Appendix X3, and the References. 1.8 Guidelines for the required data needed for subcommittee A01.14 to consider listing a lean duplex stainless steel in this standard test method are given in Annex A1. 1.9 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to other units that are provided for information only and are not considered standard. 1 This test method is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.14 on Methods of Corrosion Testing. Current edition approved June 1, 2022. Published June 2022. Originally approved in 2013. Last previous edition approved in 2015 as A1084 – 15a. DOI: 10.1520/A1084 – 15AR22. Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. 1 1.10 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.11 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

ASTM A1084-15a(2022) Referenced Document

• ASTM A370 Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• ASTM A923 Standard Test Methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic/Ferritic Stainless Steels
• ASTM E23 Standard Test Methods for Notched Bar Impact Testing of Metallic Materials
• ASTM E6 Standard Terminology Relating to Methods of Mechanical Testing
• ASTM G15 Standard Terminology Relating to Corrosion and Corrosion Testing
• ASTM G48 Standard Test Methods for Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by Use of Ferric Chloride Solution

ASTM A1084-15a(2022) history

• 2022 ASTM A1084-15a(2022) Standard Test Method for Detecting Detrimental Phases in Lean Duplex Austenitic/Ferritic Stainless Steels
• 2015 ASTM A1084-15a Standard Test Method for Detecting Detrimental Phases in Lean Duplex Austenitic/Ferritic Stainless Steels
• 2015 ASTM A1084-15 Standard Test Method for Detecting Detrimental Phases in Lean Duplex Austenitic/Ferritic Stainless Steels
• 2013 ASTM A1084-13 Standard Test Method for Detecting Detrimental Phases in Lean Duplex Austenitic/Ferritic Stainless Steels