1、PD ISO/TR 16203:2016 Corrosion of metals and alloys Guidelines for the selection of methods for particle-free erosion corrosion testing in flowing liquids BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06PD ISO/TR 16203:2016 PUBLISHED DOCUMENT National foreword This
2、Published Document is the UK implementation of ISO/TR 16203:2016. The UK participation in its preparation was entrusted to Technical Committee ISE/NFE/8, Corrosion of metals and alloys. A list of organizations represented on this committee can be obtained on request to its secretary. This publicatio
3、n does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 978 0 580 71144 2 ICS 77.060 Compliance with a British Standard cannot confer immunity fro
4、m legal obligations. This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 July 2016. Amendments issued since publication Date Text affectedPD ISO/TR 16203:2016 ISO 2016 Corrosion of metals and alloys Guidelines for the selection of methods fo
5、r particle-free erosion corrosion testing in flowing liquids Corrosion des mtaux et alliages Lignes directrices pour la slection des mthodes dessai drosion-corrosion exempte de particule dans des liquides en mouvement TECHNICAL REPORT ISO/TR 16203 Reference number ISO/TR 16203:2016(E) First edition
6、2016-07-15PD ISO/TR 16203:2016ISO/TR 16203:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electron
7、ic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier
8、, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.orgPD ISO/TR 16203:2016ISO/TR 16203:2016(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 Terms and definitions . 1 4 Principles . 1 5 Test methods . 2 5.1 Tests for uniform corrosion . 2 5.1
9、.1 Rotating cylinder test . 2 5.1.2 Test in a pipe or channel . 2 5.2 Tests for localized corrosion . 3 5.2.1 Rotating disc test . 3 5.2.2 Test in a pipe or channel with changes in flow cross section 4 5.2.3 Jet impingement test 4 6 Guidelines 5 6.1 General guidelines 5 6.2 Applications and limitati
10、ons of tests 6 Bibliography 8 ISO 2016 All rights reserved iii Contents PagePD ISO/TR 16203:2016ISO/TR 16203:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Stand
11、ards 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 represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also ta
12、ke part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In p
13、articular 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 the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements
14、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 during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (se
15、e 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 meaning of ISO specific terms and expressions related to conformit y assessment, as well as information about ISOs adherenc
16、e to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html. The committee responsible for this document is ISO/TC 156, Corrosion of metals and alloys.iv ISO 2016 All rights reservedPD ISO/TR 16203:2016ISO/TR 16203:
17、2016(E) Introduction Particle-free erosion corrosion is a major problem in industries handling liquids flowing rapidly that are corrosive especially at high temperatures and high pressures. This mode of corrosion usually leads to rapid metal loss with possibly catastrophic consequences. In order to
18、prevent, mitigate and control the problems, it is important to determine the resistance to corrosion of materials accurately. This may be achieved by the use of test methods reproducing a specific mode of erosion corrosion. ISO 2016 All rights reserved vPD ISO/TR 16203:2016PD ISO/TR 16203:2016Corros
19、ion of metals and alloys Guidelines for the selection of methods for particle-free erosion corrosion testing in flowing liquids 1 Scope This Technical Report provides information on the erosion corrosion test of materials in single-phase flowing liquids and guidance for selection of test methods. 2
20、Normative references The following documents, in whole or in part, are normatively referenced 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 amendme
21、nts) applies. ISO 8044, Corrosion of metals and alloys Basic terms and definitions 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply. 3.1 erosion progressive loss of original material from a solid surface due to mechanical
22、interaction between the surface and a fluid, a multicomponent fluid, or impinging liquid or solid particles 3.2 erosion corrosion process involving conjoint corrosion and erosion 3.3 particle free erosion corrosion corrosion of metallic materials in single phase flowing liquids 4 Principles 4.1 Eros
23、ion corrosion describes the mechanical removal of metals leading to enhanced corrosion. The process is synergistic in the sense that the localized loss of material can create additional turbulent flow that encourages further film removal or even prevents its formation. The conditions in which erosio
24、n corrosion occurs will be a sensitive function of the application but there are a range of laboratory test methods that have been developed to simulate typical service applications and can provide a basis for assessing the relative susceptibility of materials to damage development. 4.2 Erosion corr
25、osion test is conducted either by setting up a uniform flow velocity distribution or by inducing different flow velocities or different rates of corrosion over the surface of test specimen. In the former, corrosion damage increases as the flow velocity of liquid increases, while in the latter, the d
26、amage increases as the difference in the corrosion rates becomes larger. TECHNICAL REPORT ISO/TR 16203:2016(E) ISO 2016 All rights reserved 1PD ISO/TR 16203:2016ISO/TR 16203:2016(E) 5 Test methods 5.1 Tests for uniform corrosion 5.1.1 Rotating cylinder test This test uses a cylinder-shaped specimen
27、insulated at the top and bottom end (see Figure 1). The cylindrical surface is the test surface. It is attached with a shaft at the top end with which it is rotated around the longitudinal axis in test solution. The radius of the cylinder may be chosen freely, but needs to be constant along the long
28、itudinal distance, so that a uniform distribution of circumferential flow velocity over the entire surface of specimen is achieved. This test is widely used for elucidating the effect of flow velocity on the uniform corrosion. Figure 1 Rotating cylinder test 5.1.2 Test in a pipe or channel The flat
29、plate specimen installed in the pipe line (the hatched part, upper in Figure 2) and the test specimens embedded in the wall of the duct (the hatched part, lower in Figure 2) are also used for investigating the effect of flow velocity on uniform corrosion. Because of the end effect, the specimen embe
30、dded in the wall of the duct is advantageous over the pipe. However, the former has some difficulties in setting the specimen precisely flat with the duct wall.2 ISO 2016 All rights reservedPD ISO/TR 16203:2016ISO/TR 16203:2016(E) Figure 2 Test in a pipe or channel with specimen surfaces parallel to
31、 the flow direction 5.2 Tests for localized corrosion 5.2.1 Rotating disc test In this method, a circular disc with comparably smaller thickness is rotated horizontally around the vertical shaft which is attached vertically at the centre (see Figure 3). The test surface is the underside surface of t
32、he disc over which the flow velocity distribution is not uniform but distributed. This is the main reason why the localized corrosion of erosion corrosion type can be developed in the rotating disc unlike in the rotating cylinder test. However, the distribution of flow velocity may deviate from the
33、theoretical calculation because the circumferential flow through the disc rotation is overlapped with the radial secondary flow as is shown in Figure 3 with the curved arrows. ISO 2016 All rights reserved 3PD ISO/TR 16203:2016ISO/TR 16203:2016(E) Figure 3 Rotating disc test 5.2.2 Test in a pipe or c
34、hannel with changes in flow cross section A water tunnel with sudden convergence and divergence in the cross section of liquid flow (see Figure 4) is used to produce the localized corrosion of differential flow-velocity corrosion type on the inside surface of the tunnel wall, which is essentially th
35、e test surface. Stagnant volume of fluid or fixed vortexes may be built at the downstream of the boundary layer separation points, which are usually located at the corner tips where the cross section of flow changes suddenly (the thin hatched part in Figure 4). Therefore, the flow velocity distribut
36、ion is not uniform along the flow axis, unlike that without change in the flow cross section, and localized corrosion occurs in this test. Figure 4 Test in flow tunnel with sudden convergence and divergence 5.2.3 Jet impingement test This test uses three types of jets: free jet; submerged jet; and j
37、et-in-slit (see Figure 5). The free jet is used in conventional impingement tests, where the liquid jet strikes at a right angle to the specimen surface in the air. The submerged jet is a jet submerged in solution. The jet injected into a narrow gap has been named as jet-in-slit. Typically, the insi
38、de diameter of the nozzle is 1,6 mm; the gap between the nozzle top end and the specimen is 0,8 mm; and the flow rate of the test liquid is 0,4 l/min. At this flow rate, the fluid velocity at the nozzle outlet is around 3,3 m/s, and the Reynolds number at that point is 8 100.4 ISO 2016 All rights re
39、servedPD ISO/TR 16203:2016ISO/TR 16203:2016(E) (a) free jet (b) submerged jet (c) jet-in slit Figure 5 Impinging jets used to evaluate localized corrosion 6 Guidelines 6.1 General guidelines 6.1.1 In selecting test methods, it is necessary to decide which mode of corrosion is intended to be produced
40、: uniform corrosion or localized corrosion. For the latter especially, factors should be chosen that produce the difference in corrosion rates over the specimen surface, i.e. shear force, turbulence in the flow, flow velocity difference, fixed vortex or active/passive states. 6.1.2 The flow conditio
41、ns over the specimen surface should be clearly verified, irrespective of the test method chosen. 6.1.3 It is important to reproduce the wall shear stress in the practical applications at the specimen surface as closely as possible. For the rotating disc method use Formula (1): ws= 6,302Re .0.5(1) Fo
42、r the rotating cylinder method use Formula (2): ws= 0,079 1 2r 2 Re -0.3(2) For the impinging jet method use Formula (3): ws= 0,044 7u 0 2 Re -0.182(x/d jet ) 2(3) For the flow channel method use Formula (4): ws= d(P/L)/4 (4) where ISO 2016 All rights reserved 5PD ISO/TR 16203:2016ISO/TR 16203:2016(
43、E) ws is wall shear stress, measured in Pa; is angular velocity, measured in radian/sec; is the solution density, measured in kg m -3 ; is the kinetic viscosity of the solution, measured in m 2s 1 ;Re is the Reynolds number;r is the radius of rotating cylinder, measured in m;d jet is the inner diame
44、ter of the jet nozzle, measured in m;u 0 is the fluid velocity at the front of the jet nozzle, measured in m s 1 ;x is the radial distance from the jet nozzle centre line, measured in m; P is the pressure drop; L is the length of the pipe; d is the diameter. 6.1.4 Specimens should be insulated from
45、the holder to avoid galvanic corrosion. 6.1.5 The test set-up, which can accommodate multiple specimens in the same run, is conveniently used for comparative tests of materials. Specimen should be small in weight but large in surface area to determine the amount of damage so that even a small loss c
46、an be measured, and it is possible to shorten the testing time. A specimen with a flat surface is recommended not only for easy surface finishing before test but also for observations after test. 6.1.6 The rate of damage in wall thinning rate or in penetration rate with the dimension of (mm h 1 ) is
47、 useful. 6.2 Applications and limitations of tests Applications and limitations of each test methods for particle-free erosion corrosion in flowing liquids are listed in Table 1.6 ISO 2016 All rights reservedPD ISO/TR 16203:2016ISO/TR 16203:2016(E) Table 1 Applications and limitations of tests Metho
48、d Applications Limitations Rotating cylinder Types of reproducible corrosion: uniform corrosion Corrosion damage information: wall thinning or penetration rate cumulative measurement of damage Information on materials performance in the field: qualitative evaluation or the order of merit of the mate
49、rials tested Testing in single phase liquid only for the equations to apply Maintaining good electrical contact with the rotating electrodes is difficult Testing under high pressure is difficult Rotating disc Types of reproducible localized corrosion: erosion corrosion due to shear force differential flow velocity corrosion Corrosion damage information: damage depth distribution over the specimen surface cumulative measurement of damage Information on materia
