1、BSI Standards PublicationBS ISO 17248:2015Corrosion of metals andalloys Test method forhigh temperature corrosiontesting of metallic materialsby embedding in salt, ash, orother solidsBS ISO 17248:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 17248:2015.T
2、he UK participation in its preparation was entrusted to TechnicalCommittee ISE/NFE/8, Corrosion of metals and alloys.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract
3、. Users are responsible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 78212 1ICS 77.060Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of
4、 theStandards Policy and Strategy Committee on 30 April 2015.Amendments issued since publicationDate Text affectedBS ISO 17248:2015 ISO 2015Corrosion of metals and alloys Test method for high temperature corrosion testing of metallic materials by embedding in salt, ash, or other solidsCorrosion des
5、mtaux et alliages Mthode dessai pour essais de corrosion haute temprature de matriaux mtalliques par enfouissement dans du sel, des cendres ou dautres solidesINTERNATIONAL STANDARDISO17248First edition2015-04-15Reference numberISO 17248:2015(E)BS ISO 17248:2015ISO 17248:2015(E)ii ISO 2015 All rights
6、 reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior w
7、ritten permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO
8、 17248:2015ISO 17248:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 24 Test method . 24.1 Principle 24.2 Reagents and materials . 24.2.1 Test pieces . 24.2.2 Corrosive powder 34.3 Test apparatus . 34.3.1 Design of apparatus . 34.3.2 Temperature monitorin
9、g 44.3.3 Gas supply 54.4 Procedure 54.4.1 Preparation and placement of the test piece . 54.4.2 Test environment 64.4.3 Heating method 64.4.4 Test duration . 64.4.5 Cooling of test pieces 74.4.6 Discontinuous testing 74.5 Determination of mass change 74.5.1 Principle 74.5.2 Measurements prior to test
10、ing 74.5.3 Descaling prior to mass determination 74.5.4 Measurement of corrosion mass loss . 85 Examination of surface and microstructure of corroded test pieces . 86 Report 86.1 Matters to be described . 86.1.1 Test material 86.1.2 Test piece 96.1.3 Testing environments 96.1.4 Test results 96.2 Sup
11、plementary note 10Annex A (informative) Chemical and electrolytic procedures for removal of corrosion products from fully embedded test pieces .11Bibliography .14 ISO 2015 All rights reserved iiiContents PageBS ISO 17248:2015ISO 17248:2015(E)ForewordISO (the International Organization for Standardiz
12、ation) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be
13、 represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to
14、 develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of th
15、e ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified dur
16、ing the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the mea
17、ning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT), see the following URL: Foreword Supplementary information .The committee responsible for this document is ISO/TC 15
18、6, Corrosion of metals and alloys.iv ISO 2015 All rights reservedBS ISO 17248:2015ISO 17248:2015(E)IntroductionIn contrast to high temperature corrosion occurring in a gaseous environment, which is covered in ISO 21608 and ISO 13573, this International Standard focuses on high temperature corrosion
19、occurring on materials that are in direct contact with solid corrosive substances, commonly referred to as under-deposit corrosion.This International Standard considers the case of a metallic material embedded, partially or completely, in a corrosive powder that is present in abundance and remains c
20、ompletely or partially in the solid state throughout high temperature exposure. Partially embedded test pieces offer the advantage of allowing investigation of corrosion at three different positions, i.e. under the powder, at the powder/gas phase interface, and in the gas phase above the corrosive p
21、owder.The closely-related condition involving immersion in a molten salt or other liquid is described in ISO 17245, and that involving application of a surface deposit of salt, ash, or other substances in ISO 17224. ISO 2015 All rights reserved vBS ISO 17248:2015BS ISO 17248:2015Corrosion of metals
22、and alloys Test method for high temperature corrosion testing of metallic materials by embedding in salt, ash, or other solids1 ScopeThis International Standard specifies the method for high temperature corrosion testing of metallic materials by embedding in a corrosive powder made up of salt, ash,
23、and/or other solids and exposing them to high temperature in a controlled gas environment to evaluate their corrosion resistance.Two options exist: fully embedding and partially embedding.Fully embedding is used in cases in which a mass change measurement is required.Partially embedding is used to i
24、nvestigate three potentially different interaction zones on a single test piece, i.e. the embedded part, the non-embedded part, and the gas/powder interface region. Therefore, gravimetric measurements are not appropriate and metallographic investigations are necessary instead.This International Stan
25、dard does not cover methods where test pieces are immersed in a liquid or cases in which a surface deposit is applied to the test pieces. These methods are covered in ISO 17245 and ISO 17224, respectively.2 Normative referencesThe following documents, in whole or in part, are normatively referenced
26、in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3611, Geometrical product specifications (GPS) Dimensional measuring equipmen
27、t: Micrometers for external measurements Design and metrological characteristicsISO 6906, Vernier callipers reading to 0,02 mmISO 8044, Corrosion of metals and alloys Basic terms and definitionsISO 8407:2009, Corrosion of metals and alloys Removal of corrosion products from corrosion test specimensI
28、SO 21608:2012, Corrosion of metals and alloys Test method for isothermal-exposure oxidation testing under high-temperature corrosion conditions for metallic materialsISO 26146, Corrosion of metals and alloys Method for metallographic examination of samples after exposure to high-temperature corrosiv
29、e environmentsASTM E3, Standard guide for preparation of metallographic specimensASTM E220, Standard method for calibration of thermocouples by comparison techniquesASTM E230, Standard temperature-electromotive forces tables for standardized thermocouplesASTM E407, Standard practice for microetching
30、 metals and alloysASTM E1350, Standard test method for testing sheathed thermocouples prior to, during and after installationINTERNATIONAL STANDARD ISO 17248:2015(E) ISO 2015 All rights reserved 1BS ISO 17248:2015ISO 17248:2015(E)3 Terms and definitionsFor the purposes of this document, the terms an
31、d definitions given in ISO 8044 and the following apply.3.1affected layerlayer beneath the test piece surface that is affected in its composition and/or structure due to corrosion3.2corrosive powderpowder mixture made up of salt, ash, and/or other solids that contains compounds that are expected to
32、react with the metal at high temperature3.3controlled gas environmentflowing gas mixture of defined composition and flow rate which can affect the behaviour of the corrosive powder3.4descalingremoval of corrosion products and corrosive phases from the test piece surface before measurement of the mas
33、s of the remaining metal4 Test method4.1 PrincipleMass change measurements can be performed with fully embedded test pieces. In this case, the test shall be performed with at least three test pieces of each material to ensure reproducibility of the test results. Two test pieces shall be used for det
34、ermination of mass change or dimensional change, and one shall be used for observation of the surface and/or cross section.4.2 Reagents and materials4.2.1 Test piecesTest pieces for fully embedding shall have the form of a rectangular plate, a disc, or a cylinder with a minimum surface area of 300 m
35、m2and a minimum thickness of 1,5 mm.Test pieces for partially embedding shall have the form of a rectangular plate with a minimum length of 60 mm and a minimum thickness of 1,5 mm. The rectangular geometry allows accurate metallographic examinations of longitudinal sections as well as transverse sec
36、tions, which is not possible with a cylindrical test piece.If the test pieces cannot be made according to these specifications, the shape and dimensions of the test pieces shall be in accordance with the agreement between the parties involved.The test pieces shall be machined to remove the strata af
37、fected by cutting.The final finishing of the surface of the test pieces shall be performed with abrasives with a mean particle diameter of approximately 15 m. This can be achieved by the use of abrasives according to Table 1.2 ISO 2015 All rights reservedBS ISO 17248:2015ISO 17248:2015(E)Table 1 Des
38、ignation and mean diameter of particles of coated abrasives according to regional standardsStandard DesignationMean diameter mRegionFEPAa431984 R 1993: Grit Sizes for Coated AbrasivesISO 6344 Coated abrasives Grain size analysisP1200 15,3 1,0 EuropeJIS R600187 #1000 15,5 1,0 JapanANSI B74.1292 Speci
39、fications for the Size of Abrasive Grain Grinding Wheels, Polishing and General Industrial Uses600 16,0 AmericaaFederation of European Producers of Abrasives.If another surface finish is required by the parties involved, the surface finish condition shall be described.Sharp edges of test pieces migh
40、t give anomalous behaviour. These shall be slightly rounded during the final stages of test piece preparation.The dimensions of the test pieces shall be measured prior to exposure at a minimum of three positions for each dimension with a precision of 0,02 mm by means of the measuring instruments spe
41、cified in ISO 3611 and ISO 6906.After ultrasonically degreasing in isopropanol or ethanol, the test pieces shall be dried in hot air or in a desiccator.If it is suspected that test pieces might absorb significant amounts of atmospheric contaminants such as water, it is recommended that the cleaned t
42、est pieces be stored in a desiccator prior to weighing and exposure.4.2.2 Corrosive powderThe type of powder to be used in the test shall be selected in accordance with the environment for which the test is intended. The powder shall be prepared either by taking ash or deposit from actual equipment
43、or by mixing chemicals of reagent grade.The particle size of the powder shall not exceed 100 m. When using reagent grade chemicals, the particle size (according to the suppliers specification) shall be recorded.WARNING When working with dangerous substances (such as certain ashes, molten salts, heav
44、y metals, and organic materials), all necessary safety precautions shall be taken.4.3 Test apparatus4.3.1 Design of apparatusThe apparatus shall be composed as a whole, of the temperature-regulating device for heating all test pieces at a uniform temperature. The heating device shall be equipped wit
45、h a testing portion capable of separating the test pieces from outside air. The gas supply shall be controlled by a gas flow meter.A basic design of a closed, horizontal, apparatus is shown in Figure 1. Other designs can use vertical orientation. A design of the complete furnace setup is shown in IS
46、O 21608:2012, Figure 1. ISO 2015 All rights reserved 3BS ISO 17248:2015ISO 17248:2015(E)Key1 test gas inlet2 test chamber3 heating unit4 crucible5 test piece6 corrosive substance7 thermocouple8 gas exitFigure 1 Apparatus using a horizontal furnaceThe test chamber shall not be composed of materials t
47、hat react significantly with the gas environment or the corrosive substance during the test. If the reaction is not avoidable, the reaction shall be small enough to neglect a change in composition of the atmosphere.4.3.2 Temperature monitoringThe temperature distribution of the furnace shall be char
48、acterized at the exposure temperature prior to the testing to determine the width of the isothermal zone by the use of a movable thermocouple.The temperature-regulating device shall be capable of guaranteeing that the temperature of the test piece is kept within the permissible range given in Table
49、2.Table 2 Permissible tolerance of temperature of test piecesTemperature range, C 300 300 to 600 600 to 800 800 to 1 000 1 000 to 1 200 1 200Temperature tolerance, C 2 3 4 5 7 By agreementThermocouple sheaths shall be used to protect the thermocouple wires and shall fully withstand the test temperature and environment.A specimen thermocouple shall be positioned as close as possible to the test piece. If the experimental condition does not allow the use of such a thermocouple, the temperature of the
