1、BS ISO 18203:2016Steel Determination of thethickness of surface-hardenedlayersBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 18203:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18203:2016.The UK participation in i
2、ts preparation was entrusted to Technical Committee ISE/101/7, Methods of physical and metallographic testing.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Use
3、rs are responsible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 80815 9 ICS 77.040.99 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority
4、of the Standards Policy and Strategy Committee on 31 December 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 18203:2016 ISO 2016Steel Determination of the thickness of surface-hardened layersAcier Dtermination de lpaisseur des couches durcies superficiellesINTE
5、RNATIONAL STANDARDISO18203First edition2016-12-01Reference numberISO 18203:2016(E)BS ISO 18203:2016ISO 18203:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reprod
6、uced 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 written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.
7、ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 18203:2016ISO 18203:2016(E)Foreword ivIntroduction v1 Scope . 12 Normative reference . 13 Terms and definitions . 14 Symbols, abbreviations and
8、 designations 35 Principle 36 Apparatus . 37 Test specimen 47.1 Selection and preparation of samples . 47.2 Preparation of the surface to be examined . 58 Method of measurement 58.1 Hardness testing method . 58.2 Microscopic methods. 68.2.1 Total thickness of surface hardening depth (THD) 68.2.2 Com
9、pound layer thickness (CLT) . 69 Evaluation of the results . 79.1 Case hardening depth (CHD), surface hardening depth (SHD) and nitriding hardness depth (NHD) . 79.2 Total thickness of surface hardening depth (THD) 79.3 Compound layer thickness (CLT) 710 Test report . 8Annex A (normative) Interpolat
10、ion method for determining the case hardening depth . 9Annex B (informative) Examples of CLT measurements .11Bibliography .12 ISO 2016 All rights reserved iiiContents PageBS ISO 18203:2016ISO 18203:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of n
11、ational 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 represented on that committee. Inter
12、national 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 develop this document and those inte
13、nded 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 the ISO/IEC Directives, Part 2 (see www
14、.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 during the development of the document w
15、ill 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 meaning of ISO specific terms and expres
16、sions related to conformity assessment, as well as information about ISOs adherence 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 17, Steel, Subcommi
17、ttee SC 7, Methods of testing (other than mechanical tests and chemical analysis).This first edition of ISO 18203 cancels and replaces ISO 2639:2002, ISO 3754:1976 and ISO 4970:1979, which have been technically revised.iv ISO 2016 All rights reservedBS ISO 18203:2016ISO 18203:2016(E)IntroductionIn t
18、he past, there are three ISO standards for measuring surface-hardened layer. Because those standards employed almost the same principle of measuring, it is intended to make it easy for maintenance of the standards and application of test by integrating these three standards.The method of estimating
19、uncertainty of measurement is not included in this document. In future revision, uncertainty of measurement may be reflected based on real applications to this test. ISO 2016 All rights reserved vBS ISO 18203:2016BS ISO 18203:2016Steel Determination of the thickness of surface-hardened layers1 Scope
20、This document specifies a method of measuring the case hardening depth, surface hardening depth, nitriding hardness depth and total thickness of surface hardening depth obtained, e.g. thermal (flame and induction hardening, electron beam hardening, laser beam hardening, etc.) or thermochemical (carb
21、onitriding, carburizing and hardening, hardening and nitriding, etc.) treatment.NOTE Surface-hardened layer can be produced by mechanical method (shot blasting, shot peening, etc.). The depth of these layers is generally shallow. Measuring a profile of hardened depth may require lower test force of
22、hardness test.2 Normative referenceThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documen
23、t (including any amendments) applies.ISO 4545-1, Metallic materials Knoop hardness test Part 1: Test methodISO 4545-2, Metallic materials Knoop hardness test Part 2: Verification and calibration of testing machinesISO 6507-1, Metallic materials Vickers hardness test Part 1: Test methodISO 6507-2, Me
24、tallic materials Vickers hardness test Part 2: Verification and calibration of testing machines3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC
25、Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at http:/www.iso.org/obp3.1case hardening depthCHDperpendicular distance between the surface and the layer having a hardness of 550 HV in accordance with ISO 6507-1 or equivalent Knoop hardness in accordan
26、ce with ISO 4545-1Note 1 to entry: For steels which present a hardness greater than 450 HV at a distance of three times the case hardening depth (determined with a limiting hardness value of 550 HV) from the surface, a limiting hardness value greater than 550 HV, in steps of 25 units, can be selecte
27、d for the determination of the case hardening depth by agreement between interested parties.Note 2 to entry: In general, case hardening consists of carburizing or carbonitriding followed by quench hardening (see ISO 4885).INTERNATIONAL STANDARD ISO 18203:2016(E) ISO 2016 All rights reserved 1BS ISO
28、18203:2016ISO 18203:2016(E)3.2surface hardening depthSHDdistance between the surface and the layer where HV is equal to the value specified by the term “hardness limit”Note 1 to entry: Hardness limit is a function of the minimum surface hardness required for the part, given by the following formula:
29、hardness limit (HV) = A minimum surface hardness (HV)Note 2 to entry: 0,80 is usually used for A. Other values can be applied.Note 3 to entry: SHD measurement should be applied for parts which, in the surface hardened condition, have a hardness less than (hardness limit 100 HV) at a distance 3 SHD f
30、rom the surface. Where these conditions are not satisfied, the definition of SHD should be agreed between interested parties.Note 4 to entry: Recommended hardness limit values are listed in Table 1.Table 1 Recommended hardness limit values of SHDMinimum surface hardness HVHardness limit HV300 to 330
31、 250335 to 355 275360 to 385 300390 to 420 325425 to 455 350460 to 480 375485 to 515 400520 to 545 425550 to 575 450580 to 605 475610 to 635 500640 to 665 525670 to 705 550710 to 730 575735 to 765 600770 to 795 625800 to 835 650840 to 865 6753.3compound layer thicknessCLTthickness of the surface lay
32、er formed during the thermochemical treatment and made up of the chemical compounds formed by the elements introduced during the treatment and certain elements from the base metal2 ISO 2016 All rights reservedBS ISO 18203:2016ISO 18203:2016(E)3.4nitriding hardness depthNHDdistance from the surface o
33、f nitride layer to the point where the material hardness limit is 50 HV above core hardnessNote 1 to entry: The core hardness is determined by at least three hardness measurements and rounded to the nearest multiple of 10 HV.3.5total thickness of surface hardening depthTHDdistance from the examined
34、surface to the limit that shows the same hardness as the matrix hardnessNote 1 to entry: The distance is often measured by the microstructural method, which is the distance from the surface examined to the limit beyond which no visible structure variation is detected, as compared with the structure
35、of the unaffected metal. The microstructural method does not measure as deep as the hardness method.4 Symbols, abbreviations and designationsThe symbols and abbreviations used in this document and their corresponding designations are given in Table 2.Table 2 Symbols, abbreviations and designationsSy
36、mbol/ abbreviationUnit Designationdi mm distance of the centre of each impression from the surfaced mm distance of the centre of two adjacent impressionCHD mm case hardening depthSHD mm surface hardening depthCLT m compound layer thicknessNHD mm nitriding hardness depthTHD mm total thickness of surf
37、ace hardening depthHlimitHV hardness limit5 PrincipleThe case hardening depth, surface hardening depth and nitriding hardness depth are determined from the gradient of hardness on a cross-section normal to the surface.They are derived graphically from a curve representing the variation in hardness a
38、s a function of the distance from the surface of the part.The total thickness of surface hardening depth is determined from the structure variation observed by micrographic method or by measuring hardness variation.Compound layer thickness is determined from the chemical compound layer observed by m
39、icroscopic method.6 ApparatusThe hardness testing machine for determining Vickers hardness shall be verified and calibrated in accordance with ISO 6507-2. ISO 2016 All rights reserved 3BS ISO 18203:2016ISO 18203:2016(E)By agreement between the parties concerned, measurement of the Knoop hardness may
40、 be used. The hardness testing machine for determining Knoop hardness shall be verified and calibrated in accordance with ISO 4545-2.For measuring the total thickness of surface hardening depth, it is recommended that a microscope that can display the hardened layer as 1/3 to 2/3 of the view field s
41、hould be used (see ISO 1463).7 Test specimen7.1 Selection and preparation of samplesThe measurement shall be made, unless otherwise specially agreed, on a cross-section of the part in the following specified condition: a section perpendicular to the longitudinal axis of the product, or, if the produ
42、ct has no longitudinal axis, a section perpendicular to the surface at a location to be agreed between the parties concerned;For thin hardened layers, the following sample can be applied by agreement between interested parties.NOTE Because stepped test piece and oblique test piece may result in a di
43、fferent outcome from cross-section measurements, using lower test force including microhardness test to cross-section measurement is a better alternative (see ISO 6507-1, ISO 4545-1 and ISO 14577-1). a test piece with steps: These steps are precision-ground from the surface of the product to the poi
44、nt where the structure is that of the basis metal, and are 0,05 mm or 0,10 mm thick. The stepped test piece is to be used when a limiting value for the thickness of the surface layer is specified (see Figure 1 and Figure A.2); an oblique section (see Figure 2).Figure 1 Stepped test pieceKeyl distanc
45、e measurede actual depthNOTE The values of the distance measured should be adjusted by the slope (e/l).Figure 2 Oblique section4 ISO 2016 All rights reservedBS ISO 18203:2016ISO 18203:2016(E)7.2 Preparation of the surface to be examinedCut specimens for preparation with the gentlest possible techniq
46、ue, using only laboratory equipment. Mount specimens with a high-quality resin designed to provide excellent edge retention. Grind and polish using a proper sequence of abrasives to remove the damage from sectioning and grinding while maintaining edge retention. Exercise care to ensure that the regi
47、on of interest is not altered by the sample preparation. The lower the test load in hardness testing, the higher the preparation quality must be. After polishing, etch the specimen with an appropriate solution to determine if the preparation was adequate and to see if there is a modification to the
48、surface. Repeat one or more of the final preparation steps, if the quality is inadequate. Carefully clean off any films or residue on the surface. Do not touch the surface with fingers. For microindentation hardness testing, it is recommended to test an as-polished, non-etched surface. For the micro
49、graphic method, use the appropriate etch to reveal and discriminate between the different constituents present.8 Method of measurement8.1 Hardness testing methodMake hardness impressions along one or more parallel lines normal to the surface and within a band of width, W, of 1,5 mm (see Figure 3). The distance between these lines shall meet the requirement of ISO 6507-1.The distance, d, separating two adjacent impressions shall be not less than three times their diagonal (see Figure 3). The difference betw
