SVENSK STANDARD SS :2019

Transkript

1 SVENSK STANDARD SS :2019 Fastställd/Approved: Utgåva/Edition: 4 Språk/Language: engelska/english ICS: Jernkontorets skala II för kvantitativ bestämning av ickemetalliska inneslutningar i metaller och legeringar Jernkontoret s inclusion chart II for quantitative assessment of the content of non-metallic inclusions in metals and alloys

2 Standarder får världen att fungera SIS (Swedish Standards Institute) är en fristående ideell förening med medlemmar från både privat och offentlig sektor. Vi är en del av det europeiska och globala nätverk som utarbetar internationella standarder. Standarder är dokumenterad kunskap utvecklad av framstående aktörer inom industri, näringsliv och samhälle och befrämjar handel över gränser, bidrar till att processer och produkter blir säkrare samt effektiviserar din verksamhet. Delta och påverka Som medlem i SIS har du möjlighet att påverka framtida standarder inom ditt område på nationell, europeisk och global nivå. Du får samtidigt tillgång till tidig information om utvecklingen inom din bransch. Ta del av det färdiga arbetet Vi erbjuder våra kunder allt som rör standarder och deras tillämpning. Hos oss kan du köpa alla publikationer du behöver allt från enskilda standarder, tekniska rapporter och standardpaket till handböcker och onlinetjänster. Genom vår webbtjänst e-nav får du tillgång till ett lättnavigerat bibliotek där alla standarder som är aktuella för ditt företag finns tillgängliga. Standarder och handböcker är källor till kunskap. Vi säljer dem. Utveckla din kompetens och lyckas bättre i ditt arbete Hos SIS kan du gå öppna eller företagsinterna utbildningar kring innehåll och tillämpning av standarder. Genom vår närhet till den internationella utvecklingen och ISO får du rätt kunskap i rätt tid, direkt från källan. Med vår kunskap om standarders möjligheter hjälper vi våra kunder att skapa verklig nytta och lönsamhet i sina verksamheter. Vill du veta mer om SIS eller hur standarder kan effektivisera din verksamhet är du välkommen in på eller ta kontakt med oss på tel Standards make the world go round SIS (Swedish Standards Institute) is an independent non-profit organisation with members from both the private and public sectors. We are part of the European and global network that draws up international standards. Standards consist of documented knowledge developed by prominent actors within the industry, business world and society. They promote cross-border trade, they help to make processes and products safer and they streamline your organisation. Take part and have influence As a member of SIS you will have the possibility to participate in standardization activities on national, European and global level. The membership in SIS will give you the opportunity to influence future standards and gain access to early stage information about developments within your field. Get to know the finished work We offer our customers everything in connection with standards and their application. You can purchase all the publications you need from us - everything from individual standards, technical reports and standard packages through to manuals and online services. Our web service e-nav gives you access to an easy-to-navigate library where all standards that are relevant to your company are available. Standards and manuals are sources of knowledge. We sell them. Increase understanding and improve perception With SIS you can undergo either shared or in-house training in the content and application of standards. Thanks to our proximity to international development and ISO you receive the right knowledge at the right time, direct from the source. With our knowledge about the potential of standards, we assist our customers in creating tangible benefit and profitability in their organisations. If you want to know more about SIS, or how standards can streamline your organisation, please visit or contact us on phone +46 (0)

3 Denna standard ersätter SS :2016, utgåva 3. This standard supersedes the Swedish Standard SS :2016, edition 3. Copyright/Upphovsrätten till denna produkt tillhör SIS, Swedish Standards Institute, Stockholm, Sverige. Användningen av denna produkt regleras av slutanvändarlicensen som återfinns i denna produkt, se standardens sista sidor. Copyright SIS, Swedish Standards Institute, Stockholm, Sweden. All rights reserved. The use of this product is governed by the end-user licence for this product. You will find the licence in the end of this document. Upplysningar om sakinnehållet i standarden lämnas av SIS, Swedish Standards Institute, telefon Standarder kan beställas hos SIS som även lämnar allmänna upplysningar om svensk och utländsk standard. Information about the content of the standard is available from the Swedish Standards Institute (SIS), telephone Standards may be ordered from SIS, who can also provide general information about Swedish and foreign standards. Denna standard är framtagen av kommittén för Bestämning av mikrostruktur i stål, SIS/TK 121. Har du synpunkter på innehållet i den här standarden, vill du delta i ett kommande revideringsarbete eller vara med och ta fram andra standarder inom området? Gå in på - där hittar du mer information.

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5 Contents Page Introduction... iv 1 Scope Terms, definitions and designations General terms Quantifiable terms Designations Agreements before assessment Sampling Equipment for assessment of non-metallic inclusions Assessment principles Assessment of non-metallic inclusions in a field of view General Rules for assessment of a field of view Methods for evaluation General Method 1 Frequency of grades for group and type Method 2 Maximum grades for group and type Method 3 Specific agreement between parties Calculations General Calculation of grade for group Calculation of grade for type Calculation of quantitative parameters Calculation of shape factor Calculation of stringer length Reporting of results Reporting of Method 1 Frequency of grades for group and type Reporting of Method 2 Maximum grades for group and type Reporting of Method 3 Specific agreement between parties Reporting of results in accordance with other standards Annex A (normative) Algorithms for calculation of grades A.1 Calculation of grade for group A.2 Calculation of grades for type Annex B (normative) Formulas for calculation of quantitative magnitudes Annex C (informative) Examples of assessments C.1 Examples of ductile inclusions of different widths C.2 Examples of inclusions with greater length than shown in the picture chart Annex D (informative) Statistical considerations Bibliography Copyright SIS. Reproduction in any form without permission is prohibited. iii

6 Introduction Jernkontoret s inclusion chart II and this standard have been the basic pillars for steel development and the development of clean steel in Sweden. Due to the data and experience which have been gathered with the method over the years, it still plays a very important role in steel and process development. Compared to edition 3, only editorial changes and corrections have been made. Application of the standard enables quantification of all inclusions in a field of view which results in higher reproducibility than standards based on traditional comparative charts assessment of size distributions by width for all types of inclusions assessment of shape factor (reduction ratio) of ductile inclusions use of different magnifications in order to assess the presence of inclusions irrespective of size that the results of the assessment can be transformed and presented in accordance with methods in other standards. Annex A and B present all algorithms and formulas for calculation. Examples of assessment with this method are provided in Annex C. Some statistical considerations are presented in Annex D. See SIS-TR 34 for transformation of results to other standards. There is software, for example, PCMIC, which simplifies recording, calculations and the presentation of results. iv Copyright SIS. Reproduction in any form without permission is prohibited.

7 1 Scope This standard describes a method for assessment and reporting of quantity, size, morphology and distribution of non-metallic inclusions in plastic wrought steel, metals and alloys with the help of a Light Optical Microscope (LOM) and a comparative chart. The pictures in the chart are based on the logarithmic Gauss- (Galton) distribution with respect to the inclusion size. The method described in this standard is primarily intended for inclusions in plastic wrought metallic materials but can also be used for cast and sintered steels. NOTE The chemical composition of the inclusions does not form the basis of categorisation. 2 Terms, definitions and references For the purposes of this document, the following terms and definitions apply. 2.1 General terms grade quantified step of nominal density specified in a picture chart group category based on inclusion width size class step in the geometric series of widths inclusion generic term for a type of microstructural constituent sample macroscopic unit intended to be analysed specimen surface prepared surface intended for examination stringer sequence of minimum three inclusions arranged at a mutual distance which is less than 40 µm in the working direction and less than 10 µm mutual displacement transverse the working direction. Note 1 to entry See figure 1 for length, width and distance between inclusions in a stringer type category based on inclusion morphology 2.2 Quantifiable terms width maximum projected spread of an inclusion or a stringer transverse the working direction Copyright SIS. Reproduction in any form without permission is prohibited. 1

8 2.2.2 shape factor anisotropy measure which states the relationship between length and width of an inclusion length maximum projected spread of an inclusion or a stringer in the working direction field of view area surrounded by etched frame in an ocular or which is demarcated by an aperture and which forms the basis of manual or automatic assessment KEY In order to be assessed as a stringer, the distance t and s shall be less than 40 µm and 10 µm respectively. Figure 1 Length (l), width (w) and distance (s, t) of and between inclusions in a stringer 2 Copyright SIS. Reproduction in any form without permission is prohibited.

9 2.3 Designations Table 1 Designations and their meaning Designation Description Unit Other Quantifiable magnitudes Grade Group Type A B C D X T M H S P G Gmax G GA GL GN Ductile inclusions Brittle inclusions Brittle-ductile inclusions Undeformed inclusions Designation for extra thin inclusions with a width which is less than that represented by the picture chart Designation for thin inclusions Designation for medium inclusions Designation for heavy inclusions Designation for almost spherical inclusions of type A Designation for extra heavy inclusions with a width which is greater than that represented by the picture chart Grade Maximum calculated grade for a specific type Calculated mean grade Grade with respect to area Grade with respect to length Grade with respect to the number of inclusions Note: Type and group are given as exponent, for example, G A AT. d Diameter of field of view mm a Side length for square field of view Side length in the working direction for rectangular field of view b side length transverse the working direction for rectangular field of view mm SD The field of view s diameter, side length (square field of view) or side length in the working direction (rectangular field of view) mm li Inclusion length µm ls Stringer length µm lmin Minimum inclusion length µm wi Inclusion width µm ws Stringer width µm Li Ls Wi Ws Ws n k Inclusion length Stringer length Inclusion width Stringer width Mean width of a stringer Number of inclusions Number of stringer t Distance along the working direction between inclusions in a stringer µm s Distance transverse the working direction between inclusions in a stringer µm F c Factor for repetition of a comparative picture Shape factor Copyright SIS. Reproduction in any form without permission is prohibited. 3

10 3 Agreements before assessment The following items should be given in a product standard, or a delivery requirement, or be agreed between the relevant parties: Assessment alternative The size of the inclusions which shall be covered by the assessment The diameter of the field of view or the field of view s side length (for use of the frequency method, see 7.3.2) Scope of the assessment Position of the samples and specimens surfaces in the product Reporting of results Acceptance requirements. 4 Sampling Requirements for sampling and sampling scope are normally specified in a product standard or by other agreements. In the absence of requirements, at least mm 2 should be examined, distributed over at least 6 representative samples. The total individual specimen surface should permit examination of minimum 160 mm 2. For wrought steel, the specimen pieces shall be taken out so that the assessment can be conducted in the working direction. However, for assessment of the distribution of inclusions transverse the working direction, transverse samples should be taken out. The picture chart and the standardised assessment methods shall then be used with care and good judgement as they have been developed for assessment in the working direction. NOTE In all respects the statistical data is decisive for the relevance of the analysis, see Annex D. 5 Equipment for assessment of non-metallic inclusions Equipment in accordance with 5.1, 5.2 and 5.3 shall be used for the assessment: 5.1 Microscope with which assessments can be made at different magnifications 5.2 Ocular with a calibrated measurement scale 5.3 Picture chart, JK-II. 5.4 A customised software for registration of fields of view assessments and calculation of results may be used. 6 Assessment principles Study the number, length and width of inclusions in a microscope. Assess the inclusions type by comparison with standard pictures in a picture chart with quantified steps, grades see figure 2. The comparative pictures can be combined to obtain the relevant field of view, see clause 7. The picture in figure 2 shows a reduced reproduction of the picture chart JK-II. NOTE Figure 2 is not suitable as grounds for assessment. A full-size picture chart can be ordered from SIS. 4 Copyright SIS. Reproduction in any form without permission is prohibited.

11 Figure 2 Facsimile of Jernkontoret s inclusion chart II (JK-II) Copyright SIS. Reproduction in any form without permission is prohibited. 5