1、DEUTSCHE NORM Auaust 199% Determination of resistance to intergranular corrosion of stainless steels Part 2: Ferritic, austenitic and ferritic-austenitic (duplex) stainless steels - English version of DIN EN IS0 3651-2 Corrosion test in media containing sulfuric acid (IS0 3651-2 : 1998) DIN - EN IS0
2、 3651 -2 ICs 77.060 Descriptors: Stainless steel, corrosion resistance, testing. Supersedes DIN 5091 4, September 1996 edition. Ermittlung der Bestndigkeit nichtrostender Sthle gegen interkristalline Korrosion - Teil 2: Nichtrostende ferritische, austenitische und ferritisch-austenitische (Duplex-)S
3、thle - Korrosionsversuch in schwefelsurehaltigen Medien (IS0 3651 -2 : 1998) European Standard EN IS0 3651 -2 : 1998 has the status of a DIN Standard. A comma is used as the decimal marker. National foreword This standard has been published in accordance with a decision taken by ECISS/TC 1 to adopt,
4、 without alteration, International Standard IS0 3651 -2 as a European Standard. The responsible German body involved in its preparation was the Normenausschu Materialprfung (Mate- rials Testing Standards Committee), Technical Committee Korrosion und Korrosionsschutz. Amendments DIN 5091 4, September
5、 1996 edition, has been superseded by the specifications of EN IS0 3651 -2. Previous editions DIN 5091 4: 1968-09, 1970-09, 1982-04, 1984-06, 1996-09. EN comprises 11 pages. No pari of this standard may be reproduced without the prior permission of Ref. No. DIN EN IS0 3651-2 : 1998-0 Y Deutsches Ins
6、titut fr Normung e. V., Berlin. wth Verlag GmbH, D-10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). English price group O7 Sales No. 1107 12.98 EUROPEAN STANDARD NORME EUFIOPEENNE EUROPISCHE NORM EN IS03651 -2 May 1998 ICs 77.060 Descriptors: Stainless steel, corrosio
7、n resistance, testing. English version Determination of resistance to intergranular corrosion of stainless steels Part 2: Ferritic, austenitic and ferritic-austenitic (duplex) stainless steels - Corrosion test in media containing sulfuric acid (IS0 3651 -2 : 1998) Dtermination de la rsistance la cor
8、rosion intergranulaire des aciers inoxydables - Partie 2: Aciers inoxydables ferritiques, austnitiques et austno-ferritiques (duplex) - Essai de corrosion en milieux contenant de l?acide sulfurique (IS0 3651 -2 : 1998) Ermittlung der Bestndigkeit nicht- rostender Sthle gegen interkristal- line Korro
9、sion - Teil 2: Nichtrostende ferritische, austenitische und ferritisch-austenitische (Duplex-) Sthle - Korrosionsversuch in schwefelsurehaltigen Medien (IS0 3651 -2 : 1998) This European Standard was approved by CEN on 1998-03-26. CEN members are bound to comply with the CENKENELEC Internal Regulati
10、ons which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national stand- ards may be obtained on application to the Central Secretariat or to any CEN member. The Euro
11、pean Standards exist in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the nati
12、onal standards bodies of Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisati
13、on Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1998. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN IS0 3651-2 : 1998 E Page 2 EN IS0 3651 -2 : 1998 Foreword International Standard I
14、S0 3651 -2 : 1998 Determination of resistance to intergranular corrosion of stainless steels - Part 2: Ferritic, austenitic and ferritic-austenitic (duplex) stainless steels - Corrosion test in media con- taining sulfuric acid, which was prepared by ISO/TC 17 Steel of the International Organization
15、for Standardization (ISO), has been adopted by ECISS/TC 1 Steel testing as a European Standard. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, and conflicting national standards withdrawn, by November 1998 at the
16、 latest. In accordance with the CENKENELEC Internal Regulations, the national standards organizations of the follow- ing countries are bound to implement this European Standard: Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the
17、Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. Endorsement notice The text of the International Standard IS0 3651 -2 : 1998 was approved by CEN as a European Standard without any modification. Contents Page Scope Purpose of the test 2.1 Verification of the intrins
18、ic resistance of the steel to intergranular corrosion . 2.2 Inspection of the efficiency of the solution treatment _. _. . . . . . . . . . . Sensitization treatment . . . . . . 3.1 Sensitization heat treatment . 3.2 Sensitization by welding . Corrosion test 4.1 Principle . 4.2 Test pieces . 4.3 Prep
19、aration of test pieces . Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test methods , . . . . , . . . . . . . . 6.1 Method A 6.2 Method B 6.3 Method C 6.4 Bend test Evaluation . . . . . . . . . .
20、. . , . , , . . . , . . . . . , . . . . . . . . . . , . . . . . . Test report . Annex A (informative) Examples of application Annex B (informative) Comparison of commonly available national standards and this part of IS0 3651 3 3 3 4 4 4 4 4 4 4 6 7 7 7 7 8 8 9 9 10 11 Page 3 EN IS0 3651 -2 : 1998 I
21、ntroduction The term “intergranular corrosion test“ denotes the corrosion test carried out by means of preferential attack of the grain boundaries. Ferritic, austenitic and ferritic-austenitic (duplex) stainless steels may be subject to such an attack when they are held at a temperature between abou
22、t 500 “C and 1 O00 OC. This heat cycle, which may provoke sensitization to intergranular corrosion, may occur during hot-forming (forging, rolling) as the result of incorrect solution treatment or during a welding operation. NOTE- In the field of application of this test, intergranular corrosion may
23、 be connected with the presence along the grain boundaries of a chromium-depleted region due to precipitation of chromium carbides, sigma phase or other intermetallic phases. 1 Scope This part of IS0 3651 specifies methods for the determination of the resistance to intergranular corrosion of ferriti
24、c, austenitic and ferritic-austenitic (duplex) stainless steels in media containing sulfuric acid. It also specifies the purposes which may be assigned to the test. The test methods included are: - method A: the 16 Yo sulfuric acid/copper sulfate test (Monypenny Strauss test); - method B: the 35 Yo
25、sulfuric acid/copper sulfate test; - method C: the 40 Yo sulfuric acid/ferric sulfate test. The methods are applicable to stainless steels supplied in the form of cast, rolled or forged products and tubes and intended for use in a mildly oxidizing acid medium (for example, sulfuric acid, phosphoric
26、acid). Unless specified in the product standard, the method to be used, A, 6 or C, shall form the subject of an agreement between the interested parties. Annex A gives examples of application of the three methods on stainless steels. NOTE - It is important to note that the result of the corrosion te
27、st is only strictly valid for the corrosive medium used in the test. It constitutes a basis for estimating the resistance to intergranular corrosion but may not be used to check resistance to other forms of corrosion (general corrosion, pitting, stress corrosion, etc.). It is necessary for the user
28、to adapt the specified corrosion test to the use which will be made of the alloy. These test should, in no case, be considered as an absolute criterion of the quality of the metal. 2 Purpose of the test This intergranular corrosion test may have either of the purposes given in 2.1 and 2.2. 2.1 Verif
29、ication of the intrinsic resistance of the steel to intergranular corrosion This verification applies only to low carbon steels (C s 0,03 %) and stabilized steels specified for resistance to intergranular corrosion. The metal is inspected after having undergone a heat treatment for sensitization whi
30、ch can be a heat treatment or welding for sensitization (see clause 3). Page 4 EN IS0 3651 -2 : 1998 2.2 Inspection of the efficiency of the solution treatment This inspection is only carried out on thin products for which the cooling speed may be made sufficiently rapid. It is only of interest for
31、the steels which are not defined in 2.1. The metal is inspected in the state in which it is delivered to the user, without heat treatment for sensitization. 3 Sensitization treatment 3.1 Sensitization heat treatment In order to verify the intrinsic resistance to intergranular corrosion (see 2.1), it
32、 is necessary to carry out a heat treatment for sensitization for stabilized steels and steels with low carbon content. The sensitization heat treatment can be: - T1: heating the specimen at 700 “C k 10 “C for 30 minutes followed by water cooling; - T2: heating the specimen at 650 “C f 1 O “C for 1
33、O minutes followed by water cooling The above defined treatments only apply to austenitic and duplex steels. The type of sensitization heat treatment shall be defined in the product standard or in the order. If not specified, heat treatment TI shall be applied. 3.2 Sensitization by welding Sensitiza
34、tion by the preparation of welded test pieces may be used as an alternative to 3.1, by agreement between the interested parties. Test pieces which are not solution annealed after welding shall be tested in the as-welded condition. No additional sensitization heat treatment shall be performed. Sensit
35、ization by welding applies to all the stainless steels covered by this part of IS0 3651. 4 Corrosion test 4.1 Principle A test piece, prepared as specified in 4.2 and 4.3, is immersed in a solution according to method A, B or C for a specified time. The test piece is then subjected to a bend test. T
36、he convex surface of the test piece is examined after bending in order to reveal any cracks caused by intergranular corrosion. For small diameter tubes, up to 60 mm (tube diameter shall be compatible with the aperture of the flask containing the solution), a flattening test is used instead of the be
37、nd test. 4.2 Test pieces 4.2.1 Dimensions The test piece shall have a total surface area of 15 cm2 to 35 cm2. In the case of sheets with a thickness greater than 6 mm, the test piece shall have a maximum thickness of 6 mm and one of the rolled surfaces shall be retained. Page 5 EN IS0 3651 -2 : 1998
38、 The test pieces are selected from the product as defined in the product standard. In case of dispute, a flat test piece, when possible, shall be used having the following dimensions. These dimensions should be used in relation to the available bending apparat: - thickness between 2 mm and 6 mrn; -
39、width at least 10 mm; - length at least 50 mm. 4.2.2 Welded test pieces Welded test pieces are prepared as follows. For flat products, two pieces about 100 mm long and about 50 mm wide are welded together and the test piece is cut according to figure 1. For tubes with a circumferential weld, the tes
40、t piece is cut according to figure 2. When four pieces are welded together to form a cross weld, the first-laid weld bead shall be in the longitudinal direction of the test piece as shown in figure 3. If the thickness of the material is 6 mm the test piece shall be machined down to 6 mm from one sid
41、e. The retained surface shall form the convex side of the test piece after bending. For welded tubes with outer diameter over 60 mm, the test pieces with length of at least 50 mm and width of at least 20 mm are prepared as shown in figure 4. For welded tubes up to 60 mm outside diameter, the test pi
42、ece shall be a full cross section of the tube and will be subject to a flattening test (see 6.4). Dimensions in millimetres 1 2 Key 1 Weld 2 Axis of the bending mandrel Figure 1 - Test piece for testing of plates and strips with welded butt joint 1 Key 1 Weld Figure 2 -Test piece for testing of tube
43、 with welded butt joint Page 6 EN IS0 3651 -2 : 1998 L / 1 Key 1 Weld 2 Axis of the bending mandrel Figure 3 - Test piece for testing of plates and strip with cross welded butt joint Figure 4 - Test piece for testing the longitudinal weld of welded tubes 4.3 Preparation of test pieces Depending on t
44、he purpose of the test (see clause 2), the test piece, either with or without sensitization treatment, shall be prepared as specified in either 4.3.1 or 4.3.2. Unless otherwise stated on the order, the method of preparation shall be left to the manufacturer and shall be recorded in the test report.
45、4.3.1 Mechanical preparation The test piece shall be descaled mechanically by grinding in the longitudinal plane on all surfaces and sharp edges with grade 120 or finer, iron-free abrasive paper or cloth. Over-heating of the test piece shall be avoided. 4.3.2 Chemical preparation In order to have a
46、surface free of oxide without any previous mechanical treatment the test piece shall be descaled for no more than one hour, either in a solution of 50 volumes of hydrochloric acid in a solution 50 volumes of hydrochloric acid and 50 volumes of water at ambient temperature. = 1,19 g/ml), 5 volumes of
47、 nitric acid (pz0 = 1,40 g/mi) and 50 volumes of water at 50 to 60 OC, or In the case of the chemical preparation, it shall be necessary to ensure in advance that intergranular corrosion does not occur due to the preparation. This should be achieved by micro examination of samples of each steel grad
48、e tested. Page 7 EN IS0 3651 -2 : 1998 4.3.3 Degreasing The test piece shall be degreased in a suitable nonchlorinated agent, rinsed and dried before being placed in the corrosive solution. 5 Apparatus 5.1 condenser with at least four balls. Erlenmeyer flask, capacity 1 I, or other suitable flask of
49、 optional capacity fitted, with an Allihn 5.2 Support for the test piece, generally of glass, for method C. 5.3 Heating device, to keep the solution boiling. 6 Test methods 6.1 Method A: The 16 % sulfuric acidkopper sulfate test (Strauss test) 6.1.1 Corrosive solution The test solution shall be prepared as follows using analytical quality reagents Dissolve 1 O0 g of copper (li) sulfate pentahydrate (CuS0,-5H20) in 700 ml of distilled water. Then add 184 g (100 mi) of sulfuric acid (p20 = 1,84 g/ml) and make up to 1 O00 ml with distilled water. 6.1.2 Procedur
