1、Designation: A1084 13A1084 15Standard Test Method forDetecting Detrimental Phases in Lean Duplex Austenitic/Ferritic Stainless Steels1This standard is issued under the fixed designation A1084; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The purpose of this test method is to allow detection of the presence of detrimental chromium-co
3、ntaining phases in selectedlean duplex stainless steels to the extent that toughness or corrosion resistance is affected significantly. Such phases can formduring manufacture and fabrication of lean duplex products. This test method does not necessarily detect losses of toughness norcorrosion resist
4、ance attributable to other causes, nor will it identify the exact type of detrimental phases that caused any loss oftoughness 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
5、 of 30-70 % 30 to 70 % ferritecontent with a typical alloy composition having Cr 17 % and Mo 1 % and with additions of Nickel, Manganese, Nitrogen andcontrolled low carbon content as well as other alloying elements. This standard test method applies only to those alloys listed inTable 1. Similar tes
6、t methods for some higher alloyed duplex stainless steels are described in ASTM Test Methods A923, but theprocedures 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
7、 detrimental chromium-containing compounds such asnitrides and carbides and other undesirable phases. Typically this occurs during exposures in the temperature range fromapproximately 300 to 955C (570 to 1750F) with a maximum susceptibility in the temperature range around 650 to 750C (1200to 1385F).
8、 The speed of these precipitation reactions is a function of composition and the thermal or thermo-mechanical historyof 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 sta
9、inless steels only exhibit a minor susceptibility to sigma or othertypes of molybdenum containing intermetallic phases. Heat treatment, that could lead to formation of small amounts ofmolybdenum containing intermetallics, would result in a large amount of precipitation of detrimental nitrides or car
10、bides longbefore 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 thesedetrimental phases as well as minimizing Cr-depletion in the matrix phase in the immediate vici
11、nity of these phases. Adequatelyrapid cooling of the product from a suitable annealing temperature provides the maximum resistance to formation of detrimentalphases by subsequent thermal exposures. For details of the proper annealing temperature recommendations for the alloy andproduct in question,
12、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 necessarilyindicate the absence of detrimental phases in the product.1.7 These test methods include the following:
13、1.7.1 Test Method AEtch Method for detecting the presence of potentially detrimental phases in Lean Duplex Stainless Steels1.7.2 Test Method BCharpy V-notch Impact Test for determining the presence of detrimental phases in Lean Duplex StainlessSteels.1.7.3 Test Method CInhibited Ferric Chloride Corr
14、osion Test for determining the presence of detrimental phases in LeanDuplex Stainless Steels.1.7.4 Examples of the correlation of thermal exposures, the occurrence of detrimental phases, and the degradation of toughnessand corrosion resistance are given in Appendix X2, Appendix X3 and the References
15、.1.8 Guidelines for the required data needed for subcommittee A01.14A01.14 to consider listing a lean duplex stainless steel in1 This test method is under the jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee A01.14on Metho
16、ds of Corrosion Testing.Current edition approved June 1, 2013May 1, 2015. Published July 2013May 2015. Originally approved in 2013. Last previous edition approved in 2013 as A1084 13.DOI: 10.1520/A1084A1084 15.13This document is not an ASTM standard and is intended only to provide the user of an AST
17、M standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published
18、by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1this 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 pa
19、rentheses are mathematical conversionsto other units that are provided for information only and are not considered standard.1.10 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish ap
20、propriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testing of Steel ProductsA923 Test Methods for Detecting Detrimental Intermetallic Phase in Duplex A
21、ustenitic/Ferritic Stainless SteelsA1084 Test Method for Detecting Detrimental Phases in Lean Duplex Austenitic/Ferritic Stainless SteelsE6 Terminology Relating to Methods of Mechanical TestingE23 Test Methods for Notched Bar Impact Testing of Metallic MaterialsG15 Terminology Relating to Corrosion
22、and Corrosion Testing (Withdrawn 2010)3G48 Test Methods for Pitting and Crevice Corrosion Resistance of Stainless Steels and RelatedAlloys by Use of Ferric ChlorideSolution3. Terminology3.1 Definitions:3.1.1 The terminology used herein, if not specifically defined otherwise, shall be in accordance w
23、ith Terminology G15E6 andG15Terminology E6. . Definitions provided herein and not given in Terminology G15E6 or in E6G15 are limited only to thisstandard.4. Significance and Use4.1 Test Method A shall only be used to supplement the results of Test Methods B and C. It shall not be used as a rejection
24、criterion, nor shall it be used as an acceptance criterion. Test Methods B and C are intended to be the procedures giving theacceptance criteria for this standard.4.2 Test Method A can reveal potentially detrimental phases in the metallographic structure. As the precipitated detrimentalphases can be
25、 very small, this test demands high proficiency from the metallographer, especially for thinner material.4.3 The presence of detrimental phases is readily detected by Test Methods B and C provided that a sample of appropriatelocation and orientation is selected.4.4 The tests do not determine the pre
26、cise nature of the detrimental phase but rather the presence or absence to the extent thatthe normally expected toughness and corrosion resistance of the material are significantly affected.4.5 This standard covers testing of samples taken from coil, coil- and plate mill plate, sheet, tubing, piping
27、, bar and deformedbar, though some of these products might not be suitable for testing according to Method B (see Test Method B for further details).Other product forms have thus far not been sufficiently tested and documented to be an integral part of this standard, though thestandard does not proh
28、ibit testing of these product forms according to the three test methods. For these other product forms, thisstandard gives only limited and non-exhaustive guidance as to interpretation of result and associated acceptance criteria.4.6 Testing on product forms outside the present scope of this standar
29、d shall be agreed between purchaser and supplier.5. Sampling, Test Specimens, and Test Units5.1 Sampling:2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standard
30、s Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.TABLE 1 List of the Lean Duplex Grades Covered by thisStandardGradesUNS S32101,UNS S32304UNS S32101UNS S32304UNS S32202A1084 1525.1.1 Because the occurrence of detrimenta
31、l phases is a function of temperature and cooling rate, it is essential that the tests beapplied to the region of the material experiencing the conditions most likely to promote the formation of detrimental phases. Inthe case of common heat treatment, this region can be that which cooled most slowly
32、 or undergoes extremely rapid cooling.5.1.2 For practical purposes, it is considered sufficient that the sampling location for flat mill products be from a location thatis at least twice the material thickness from the as-heated edges.5.1.3 Purchaser and supplier may agree on more detailed rules reg
33、arding the sampling location.5.1.4 The number of samples as well as frequency of sampling shall be agreed between purchaser and supplier of the material.5.2 Test Specimens and Test Units:5.2.1 Details of test specimen and test unit requirements are listed together with each of the Test Methods A, B
34、and C.TEST METHOD AETCH METHOD FOR EVALUATION OF THE PRESENCE OF POTENTIALLYDETRIMENTAL PHASES IN LEAN DUPLEX STAINLESS STEELS6. Introduction6.1 The etch test in this standard shall only be used for exploratory purposes. The reason for this is the small size of thedetrimental phases typically occurr
35、ing in lean duplex stainless steels and the difficulty in achieving a fully reproducible etchstructure, which depends on factors such as specimen size and geometry, etching current and potential, composition of the leanduplex as well as the amount and type of detrimental phases present. The test met
36、hod contained in this standard is, however, thebest known metallographic procedure to show the appearance and approximate amount of detrimental phases in a lean duplexstainless steel.6.2 As there is no formal test result from the metallographic etch method, the actual test method is attached to this
37、 standard asAppendix X1.TEST METHOD BCHARPY V-NOTCH IMPACT TEST FOR DETERMINATION OF THE PRESENCE OFDETRIMENTAL PHASES IN LEAN DUPLEX STAINLESS STEELS7. Scope7.1 This test method describes the procedure for conducting the Charpy V-notch impact test as a method of detecting theprecipitation of detrim
38、ental phases in lean duplex stainless steels. The presence or absence of an indication of a detrimental phasein this test is not necessarily a measure of performance of the material in service with regard to any property other than thatmeasured directly. The Charpy V-notch procedure as applied here
39、is different from that commonly applied for the determinationof toughness and shall not be used when characterization of material toughness is the purpose of the testing.8. Significance and Use (Test Method B)8.1 The Charpy V-notch impact test may be used to evaluate mill products, provided that it
40、is possible to obtain a specimen ofthe proper size from a relevant location.8.2 Charpy V-notch impact toughness of a material is affected by factors other than the presence and absence of detrimentalphases. These factors are known to include different compositions, even when the material is in fully
41、 annealed condition; smalland otherwise acceptable variations in austenite/ferrite balance; and the lamellar distance between phases. Testing transverse andlongitudinal test specimens from mill products can also give different absolute levels of impact toughness.8.3 Table 2 indicates the applicabili
42、ty and acceptance criteria for Test Method B. These acceptance criteria have been shownTABLE 2 Applicability and Acceptance Criteria for Test Method BGrade SamplingLocation TestTemperature Minimum ImpactEnergyAS32101 base metal RoomtemperatureB70 J (50 ft-lb)S32304 base metal RoomtemperatureB100 J (
43、75 ft-lb)S32202 base metal RoomtemperatureB70 J (50 ft-lb)A Energy for a full-size specimen tested in transverse direction for flat rolledproducts and tested in the longitudinal direction for bar products. Required energyfor a sub-size specimen is discussed further in sectionsubsection 10.1.3 and No
44、te2.B In this standard, room temperature is defined as the temperature range 23 5C(73 9F).A1084 153to allow for the natural variation of impact toughness in sound material tested in the transverse direction on plate and in thelongitudinal direction on bar and deformed bar, while still being able to
45、identify whether detrimental amounts of undesirable phasesare present.8.4 Acceptance criteria for Test Method B for other products including mill welded pipe, weldments and weld metal are notpresently covered by this standard, though purchaser and supplier may agree upon an acceptance criteria (see
46、Note 1). Note thatthe results of weldment testing will depend on the filler metal or weld deposit chemistry.8.5 Acceptance criteria of sub-size specimens are not covered by this standard, though purchaser and supplier may agree upona proper conversion factor of the given acceptance criteria in Table
47、 2. Conversion factors generally vary by product type anddimensions of product for which the sub-size specimen sampling is needed (see Note 2).NOTE 1As no data has been presented to A01.14subcommittee A01.14 for welded mill products or other products, no recommendation can be givenas to the acceptan
48、ce criteria for these products.Any acceptance criteria and other details of the test should be supported with data from a pre-qualificationtest in line with the minimum requirements of Annex A1 in this standard.NOTE 2As stated in Test Methods and Definitions A370, Appendix A5.3.3 and ASTM Test Metho
49、ds E23, Appendix X1.3, there is no generalcorrelation between impact values obtained with specimens of different size or shape. However, limited correlations may be established for specificationpurposes on the basis of special studies of particular materials and particular specimens. It is commonly seen that the conversion factor is set directlyproportional to the ratio between standard and sub-size specimen fracture surface area or a percentage thereof, though whether this is an acceptable wayforward to still be able to identify the presence or absence of
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