BS-ISO-4992-2-2006.pdf

BRITISH STANDARD BS ISO 4992-2:2006 Steel castings Ultrasonic examination Part 2: Steel castings for highly stressed components ICS 77.040.20; 77.140.80 ? Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS ISO 4992-2:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2006 © BSI 2006 ISBN 0 580 49669 4 National foreword This British Standard was published by BSI. It is the UK implementation of ISO 4992-2:2006. The UK participation in its preparation was entrusted to Technical Committee ISE/6, Steel castings. A list of organizations represented on ISE/6 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI Reference number ISO 4992-2:2006(E) INTERNATIONAL STANDARD ISO 4992-2 First edition 2006-02-15 Steel castings Ultrasonic examination Part 2: Steel castings for highly stressed components Pièces moulées en acier Contrôle aux ultrasons Partie 2: Pièces moulées en acier pour composants fortement sollicités BS ISO 4992-2:2006 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI iii Contents Page Foreword iv 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 2 4 Requirements 2 4.1 Order information . 2 4.2 Extent of examination. 3 4.3 Maximum permissible size of discontinuities . 3 4.4 Personnel qualification 3 4.5 Wall-section zones 4 4.6 Severity levels. 4 5 Examination. 4 5.1 Principles. 4 5.2 Material 4 5.3 Equipment, coupling medium, sensitivity and resolution of detection 5 5.4 Preparation of casting surfaces for testing . 6 5.5 Examination procedure 6 5.6 Examination report. 9 Annex A (normative) Resolution of detection of the instrument/probe combination. 16 Annex B (informative) Sound-beam diameters . 17 Annex C (informative) Types of indications 19 Bibliography. 31 BS ISO 4992-2:2006 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI iv 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 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 take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. 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. ISO 4992-2 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 11, Steel castings. ISO 4992 consists of the following parts, under the general title Steel castings Ultrasonic examination: Part 1: Steel castings for general purposes Part 2: Steel castings for highly stressed conponents BS ISO 4992-2:2006 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 1 Steel castings Ultrasonic examination Part 2: Steel castings for highly stressed components 1 Scope This part of ISO 4992 specifies the requirements for the ultrasonic examination of steel castings (with ferritic structure) for highly stressed components, and the methods for determining internal discontinuities by the pulse echo technique. This part of ISO 4992 applies to the ultrasonic examination of steel castings which have usually received a grain-refining heat treatment and which have wall thicknesses up to and including 600 mm. For greater wall thicknesses, special agreements apply with respect to the test procedure and recording levels. This part of ISO 4992 does not apply to austenitic steels and joint welds. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 5577, Non-destructive testing Ultrasonic inspection Vocabulary ISO 7963, Non-destructive testing Ultrasonic testing Specification for calibration block No. 2 EN 583-1, Non-destructive testing Ultrasonic examination Part 1: General principles EN 583-2, Non-destructive testing Ultrasonic examination Part 2: Sensitivity and range setting EN 583-5,2005, Non-destructive testing Ultrasonic examination Part 5: Characterization and sizing of discontinuities EN 1330-4, Non-destructive testing Terminology Part 4: Terms used in ultrasonic testing EN 12223, Non-destructive testing Ultrasonic examination Specification for calibration block No. 1 EN 12668-1, Non-destructive testing Characterization and verification of ultrasonic examination equipment Part 1: Instruments EN 12668-2, Non-destructive testing Characterization and verification of ultrasonic examination equipment Part 2: Probes EN 12668-3, Non-destructive testing Characterization and verification of ultrasonic examination equipment Part 3: Combined equipment BS ISO 4992-2:2006 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 2 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 5577, EN 583-1, EN 583-2, EN 583-5 and EN 1330-4, and the following, apply. 3.1 reference discontinuity echo size smallest indication to be recorded during the assessment phase of an ultrasonic examination, usually expressed as an equivalent flat-bottomed hole diameter 3.2 point discontinuity discontinuity, the dimensions of which are smaller than or equal to the sound-beam diameter NOTE Dimensions in this part of ISO 4992 relate to length, width and/or dimension in the through-wall direction. 3.3 complex discontinuity discontinuity, the dimensions of which are larger than the sound-beam diameter NOTE Dimensions in this part of ISO 4992 relate to length, width and/or dimension in the through-wall direction. 3.4 planar discontinuity discontinuity having two measurable dimensions 3.5 volumetric discontinuity discontinuity having three measurable dimensions 3.6 special rim zone outer rim-zone part with special requirements NOTE Examples of special requirements are machined surfaces, higher stresses and sealing surfaces. 3.7 production welding any welding carried out during manufacturing before final delivery to the purchaser 3.7.1 joint welding production welding used to assemble components together to obtain an integral unit 3.7.2 finishing welding production welding carried out in order to ensure the agreed quality of the casting 4 Requirements 4.1 Order information The following information shall be available at the time of enquiry and order (see also EN 583-1): the areas of the casting and the number or percentage of castings to which the ultrasonic examination requirements apply; the severity level to be applied to the various zones or areas of the casting; BS ISO 4992-2:2006 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 3 requirements for a written examination procedure; whether there are any additional requirements for the examination procedure, see also 5.5.1. 4.2 Extent of examination The casting shall be examined so that the agreed areas are totally covered (insofar as this is possible from the shape of the casting) by the use of the best applicable examination technique. For wall thicknesses greater than 600 mm, agreement shall be made between the parties concerned on the test procedure and also on the recording and acceptance levels. 4.3 Maximum permissible size of discontinuities 4.3.1 General The purchaser shall specify the acceptance level according to the required severity level for planar and volumetric discontinuities within each zone and in each specified area of the casting. The wall section shall be divided into zones as shown in Figure 1. These sections relate to the sizes of castings ready for assembly (finish machined). 4.3.2 Indications without measurable dimensions In special rim zones and at weld preparation ends, indications without measurable dimensions are limited to a maximum number of indications. These indications shall not exceed the limits given in Table 1. 4.3.3 Indications with measurable dimensions 4.3.3.1 Planar discontinuities Planar discontinuities shall not exceed the limits given in Figure 2. The area of indication with measurable length, but with a non-measurable dimension in the through-wall direction, shall be calculated in accordance with the formula given in Figure 2. The sizing of small planar discontinuities, as given in Figure 2, becomes more difficult with increasing beam- path length and sound-beam diameter. As a guide, these sizings are normally applied to a rim zone of 30 mm. This makes the use of probes with focussed beams, such as twin-crystal probes, necessary. 4.3.3.2 Volumetric discontinuities Volumetric discontinuities shall not exceed the sizes given in Figure 3 for the rim zone and Figure 4 for the core zone. Indications with measurable dimensions are not permissible in severity level 1. The area of an indication with measurable length but non-measurable width shall be calculated in accordance with the formula given in Figures 3 and 4. 4.4 Personnel qualification It is assumed that ultrasonic examination is performed by qualified and capable personnel. In order to prove this qualification, it is recommended to certify personnel according to ISO 9712 or EN 473. BS ISO 4992-2:2006 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 4 4.5 Wall-section zones The wall section shall be divided into zones as shown in Figure 1. These sections relate to the dimensions of the casting ready for assembly (finish machined). 4.6 Severity levels If the purchaser specifies different severity levels in different areas of the same casting, all of these areas shall be clearly identified on the purchaser's drawing and shall include: all necessary dimensions for accurate location of zones; the full extent of all weld preparations and the thickness of any special rim zone. Severity level 1 is only applied to weld preparations and special rim zones. Unless other requirements have been agreed by the time of acceptance of the order, for finishing welds, the requirements for the parent metal shall apply. 5 Examination 5.1 Principles The principles of ultrasonic examination given in EN 583-1, EN 583-2 and EN 583-5 shall apply. 5.2 Material The suitability of material for ultrasonic examination is assessed by comparison with the echo height of a reference reflector (usually the first backwall echo) and the noise signal. This assessment shall be carried out on selected casting areas which are representative of the surface finish and of the total thickness range. The assessment areas shall have parallel surfaces. The reference echo height according to Table 2 shall be at least 6 dB above the noise signal. If the echo height of this smallest detectable flat-bottomed or equivalent side-drilled hole diameter at the end of the test range to be assessed is less than 6 dB above the grass level, then the ultrasonic testability is reduced. In this case, the flat-bottomed or side-drilled hole diameter which can be detected with a signal-noise ratio of at least 6 dB shall be noted in the test report and the additional procedure shall be agreed between the manufacturer and the purchaser. NOTE For the definition of an adequate flat-bottomed hole size, the distance gain size system (DGS) or a test block of identical material, heat treatment condition and section thickness containing flat-bottomed holes with a diameter according to Table 2 or equivalent side-drilled holes, can be used. The following formula is used for converting the flat-bottomed hole diameter into the side-drilled hole diameter: FBH Q 2 4 4,935D D s × = × (1) where DQ is the side-drilled hole diameter, in millimetres; DFBH is the flat-bottomed hole diameter, in millimetres; is the wave length, in millimetres; s is the path length, in millimetres. The formula is applicable for DQ W 2 and s W 5 × near-field length and is only defined for single element probes. BS ISO 4992-2:2006 Licensed Copy: London South Bank University, London South Bank University, Wed Jan 10 01:41:06 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 5 5.3 Equipment, coupling medium, sensitivity and resolution of detection 5.3.1 Ultrasonic instrument The ultrasonic instrument shall meet the requirements given in EN 12668-1 and shall have the following characteristics: range setting, from at least 10 mm to 2 m continuously selectable, for longitudinal and transverse waves transmitted in steel; gain, adjustable in 2 dB maximum steps over a range of at least 80 dB with a measuring accuracy of 1 dB; time-base and vertical linearities less than 5 % of the adjustment range of the screen; suitability, at least for nominal frequencies from 1 MHz up to and including 6 MHz, in the pulse-echo technique with single-crystal and twin-crystal probes. 5.3.2 Probes and transducer frequencies The probes and transducer frequencies shall be as given in EN 12668-2 and EN 12668-3 with the following exceptions: nominal frequencies shall be in the range 1 MHz to 6 MHz; for oblique incidence, angle probes with angles betw