1、 ISO 2016 Heat-resistant steels Aciers rfractaires INTERNATIONAL STANDARD ISO 4955 Fourth edition 2016-05-01 Reference number ISO 4955:2016(E) ISO 4955:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specifi
2、ed, 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 written permission. Permission can be requested from either ISO at the address below or ISOs
3、 member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO 4955:2016(E)Foreword iv 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 2 4 D
4、esignation 2 5 Information to be supplied by the purchaser. 2 6 Classification of gr ades 3 7 Requirements 3 7.1 Manufacturing process. 3 7.2 Delivery condition 3 7.3 Chemical composition 4 7.4 Mechanical properties 4 7.4.1 Mechanical properties at room temperature 4 7.4.2 Mechanical properties at e
5、levated temperatures 4 7.5 Surface quality . 4 7.6 Internal soundness 5 7.7 Dimensions and tolerances on dimensions and shape 5 8 Inspection, testing and conformance of products 5 8.1 General . 5 8.2 Inspection procedures and types of inspection documents 6 8.3 Specific inspection and testing 6 8.3.
6、1 Extent of testing 6 8.3.2 Selection and preparation of samples and test pieces 6 8.4 Test methods . 6 8.5 Retest . 7 9 Marking 7 Annex A (informative) Technical information on heat- and creep-resistant steels .21 Annex B (informative) Data for creep strength to 1 % plastic strain and creep rupture
7、 strength .28 Annex C (informative) Designations of the steels given in Table 2 and of comparable grades covered in various designation systems .33 Annex D (informative) Applicable dimensional International Standards36 Bibliography .37 ISO 2016 All rights reserved iii Contents Page ISO 4955:2016(E)
8、Foreword ISO (the International Organization for Standardization) 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 t
9、echnical committee has been established has the right to be 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
10、 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 particular the different approval criteria needed for the different types of ISO documents should be noted. This docum
11、ent 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 of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all su
12、ch 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 (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and do
13、es not constitute an endorsement. For an explanation on the meaning 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 infor
14、mation The committee responsible for this document is ISO/TC 17, Steel, Subcommittee SC 4, Heat treatable and alloy steels. This fourth edition cancels and replaces the third edition (ISO 4955:2005), which has been technically revised.iv ISO 2016 All rights reserved INTERNATIONAL ST ANDARD ISO 4955:
15、2016(E) Heat-resistant steels 1 Scope This International Standard specifies requirements for the grades listed in Table 2, which are usually employed for products for which the resistance to the effects of hot gases and the products of combustion at temperatures in the region above 550C and/or to lo
16、ng-term mechanical stress is the main requirement. NOTE 1 Grades mentioned in this International Standard may also be used for corrosion and creep resistant purposes. This International Standard is applicable to the following: flat products; bars, sections, rod, semi-finished products and forgings.
17、NOTE 2 Hammer-forged semi-finished products (blooms, billets, slabs, etc.), seamless rolled rings and hammer-forged bars are in the following, covered under semi-finished products or bars and not under the term “forgings”. NOTE 3 Not all of the grades included in this International Standard are nece
18、ssarily available in all product forms. NOTE 4 In Table 2, two alloys are listed in addition to the steels since they belong to the heat resistant grades. NOTE 5 Heat resistant wire in the cold worked condition is covered by ISO 16143-3. NOTE 6 Corrosion resistant stainless steels for which resistan
19、ce to corrosion is of primary importance are covered by ISO 16143-1 and ISO 16143-2. NOTE 7 Heat-resistant steels for valves are covered by ISO 683-15. In addition to this International Standard, the general technical delivery requirements of ISO 404 are applicable. 2 Normative references The follow
20、ing 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 amendments) applies. ISO 377, Steel an
21、d steel products Location and preparation of samples and test pieces for mechanical testing ISO 404, Steel and steel products General technical delivery requirements ISO 4885, Ferrous products Heat treatments Vocabulary ISO/TS 4949, Steel names based on letter symbols ISO 6506-1, Metallic materials
22、Brinell hardness test Part 1: Test method ISO 6892-1:2009, Metallic materials Tensile testing Part 1: Method of test at room temperature ISO 6929, Steel products Vocabulary ISO 2016 All rights reserved 1 ISO 4955:2016(E) ISO 9443, Heat-treatable and alloy steels Surface quality classes for hot-rolle
23、d round bars and wire rods Technical delivery conditions ISO/TR 9769, Steel and iron Review of available methods of analysis ISO 10474, Steel and steel products Inspection documents ISO 14284, Steel and iron Sampling and preparation of samples for the determination of chemical composition ISO 15510,
24、 Stainless steels Chemical composition ISO 20723, Structural steels Surface condition of hot-rolled sections Delivery requirements 3 T erms a nd definiti ons For the purposes of this document, the terms and definitions given in ISO 377, ISO 404, ISO 4885, ISO 6929, ISO 14284 and the following apply.
25、 3.1 heat resistant steels heat resistant steels of this International Standard are used at above 550C (wustite point) due to their excellent resistance to the effects of hot gases and products of combustion, as well as their resistance to the influence of molten salts and molten metals but also sho
26、wing good mechanical properties during short and long-term stressing 3.2 creep resistant grades steels, nickel- or cobalt-alloys with a minimum of 8 % chromium, which are characterised by good mechanical behaviour at temperatures above 500 C under long-range service conditions, i.e. primarily by cre
27、ep strength to 1 % plastic strain or creep rupture strength during long-time stressing 4 Designation For the steel grades covered by this International Standard, the steel names as given in the tables are allocated in accordance with ISO/TS 4949. For the steel grades covered by this International St
28、andard, the steel numbers as given in the tables are allocated in accordance with ISO 15510. 5 Information to be supplied by the purchaser It shall be the responsibility of the purchaser to specify all requirements that are necessary for products under this specification. Such requirements to be con
29、sidered include, in the order listed, but not limited to, the following: the desired quantity; the product form; the number of the appropriate dimensional standard (see Annex A), the nominal dimensions, plus any choice of requirements; the type of material (grade); the number of this International S
30、tandard (ISO 4955); the name or number of the steel grade;2 ISO 2016 All rights reserved ISO 4955:2016(E) if, for the relevant steel in Tables 6 and 7 for the mechanical properties, more than one treatment condition is covered, the symbol for the desired heat treatment; the desired process route, in
31、cluding surface finish (see 7.2, 7.5 and Table 4, footnote d); if a verification of internal soundness is required, the requirements have to be agreed at the time of enquiry and order; any further optional test agreed between the manufacturer and purchaser at the time of enquiry and order; the type
32、of inspection document and its designation in accordance with ISO 10474 (see 8.2). EXAMPLE 1 ton of plates according to ISO 9444-2 with a specified thickness of 5,0 mm, a specified width of 1 200 mm, with trimmed edges (T) and a specified length of 2 500 mm made of a steel grade with the name X8NiCr
33、AlTi3221 (487608800-I) as specified in ISO 4955, in process route 1U and inspection certificate 3.1 as specified in ISO 10474: 1 t plate ISO 9444-2 5,0 1200T 2500 Steel ISO 4955 X8NiCrAlTi3221 + 1U ISO 10474 3.1 or 1 t plate ISO 9444-2 5,0 1200T 2500 Steel ISO 4955 4876-088-00-I + 1U ISO 10474 3.1 6
34、 Classific ation of gr ades Heat-resistant steels covered in this International Standard are classified according to their structure into the following: austenitic grades; ferritic grades; martensitic grades; precipitation hardening grades. 7 Requirements 7.1 Manufacturing process Unless a special s
35、teelmaking process is agreed when ordering, the steelmaking process shall be at the discretion of the manufacturer. When he so requests, the purchaser shall be informed what steelmaking process is being used. 7.2 Delivery condition The products shall be supplied in the delivery condition agreed in t
36、he order by reference to the process route given in Tables 4 and 5 (see also Annex A) and where different alternatives exist to the treatment conditions given in Tables 6 and 7. ISO 2016 All rights reserved 3 ISO 4955:2016(E) 7.3 Chemical composition 7.3.1 The chemical composition requirements given
37、 in Table 2 apply with respect to the chemical composition of the cast analysis. 7.3.2 The product analysis may deviate from the limiting values for the cast analysis given in Table 2 by values listed in Table 3. 7.4 Mechanical properties 7.4.1 Mechanical properties at room temperature The mechanica
38、l properties at room temperature as specified in Tables 6 and 7 apply for the relevant specified heat treatment condition. This does not apply to the process route 1U (hot rolled, not heat- treated, not descaled). If, by agreement at the time of ordering, the products are to be supplied in a non- he
39、at-treated condition, the mechanical properties specified in Tables 6 and 7 shall be obtainable from reference test pieces which have received the appropriate heat treatment (simulated heat treatment). 7.4.2 Mechanical properties at elevated temperatures The mechanical properties at elevated tempera
40、ture as specified in Table 8 apply for each specified heat treatment condition. This does not apply to the process route 1U (hot rolled, not heat-treated, not descaled) and to semi-finished products. The tensile test at elevated temperature shall be carried out at temperature of interest only when a
41、greed at the time of enquiry and order. If, by agreement at the time of ordering, the products are to be supplied in a non-heat-treated condition, the mechanical properties specified in Table 8 shall be obtainable from reference test pieces which have received the appropriate heat treatment (simulat
42、ed heat treatment). 7.5 Surface quality Availability, and the determination of the types of process route and surface finish (for flat products, see Table 4 and for long products, see Table 5) most suited to a particular case, should be discussed with the manufacturer. The general surface appearance
43、 with respect to soundness and surface finish shall be consistent with good production practice, for the grade and quality ordered, as determined by visual inspection. When flat products are delivered in coil form, the degree and extent of imperfections may be expected to be higher, due to the impra
44、cticability of removing short lengths of coil. Flat products delivered with hot-rolled or cold-rolled finishes (see Table 4) shall, unless otherwise agreed, be supplied with only one surface inspected to the required finish (the prime surface). In such instances, the manufacturer should indicate the
45、 prime surface, by marking the material or the packaging, or by some other agreed method. The default method is to mark the prime surface, and to make this surface the top surface of plates, sheets and cut lengths, or the outside surface of coiled products. For long products, the available surface f
46、inishes are given in Table 5. Slight surface imperfections, inherent to the production process, are permitted. Exact requirements concerning the maximum depth of acceptable discontinuities for bars, rods and sections in the relevant conditions are given in Table 1.4 ISO 2016 All rights reserved ISO
47、4955:2016(E) Table 1 Maximum depth of acceptable discontinuities for bars, rods and sections Conditions Product forms Permissible depth of discontinuities a Max. % of delivered weight in excess of permissible depth of discontinuities 1U, 1C, 1E, 1D Sections To be agreed upon at the time of enquiry a
48、nd order on the basis of ISO 20723. 1U, 1C, 1E, 1D Rounds and rod Specified at the time of enquiry and order, otherwise ISO 9443 class 1 za2. 1X b Rounds max. 0,2 mm for d 20 mm max. 0,01 d for 20 75 mm 1 % Hexagons max. 0,3 mm for d 15 mm max. 0,02 d for 15 d 63 mm 2 % Other bars max. 0,3 mm for d
49、15 mm max. 0,02 d for 15 d 63 mm 4 % 1G Rounds Technically defect free by manufacture. 0,2 % aDepth of discontinuities is understood as being the distance, measured normally to the surface, between the bottom of the discontinuities and that surface. bAt the time of enquiry and order, it may be agreed that the product shall be delivered with a surface that is technically defect free by manufacture. In this case, also the maximum % of delivere
