NORSOK M-122 (Ed. 2012)_Cast Structural Steel...
NORSOK STANDARD
M-122 Edition 2, October 2012
Cast structural steel
This NORSOK standard is developed with broad petroleum industry participation by interested parties in the Norwegian petroleum industry and is owned by the Norwegian petroleum industry represented represented by The Norwegian Oil Industry Association and The Federation of Norwegian Industry. Please note that whilst every effort has been made to ensure the accuracy of this NORSOK standard, neither The Norwegian Oil Industry Association nor The Federation of Norwegian Industry or any of their members will assume liability for any use thereof. Standards Norway is responsible for the administration and publication of this NORSOK standard. Standards Norway Strandveien 18, P.O. Box 242 N-1326 Lysaker NORWAY Copyrights reserved
Telephone: + 47 67 83 86 00 Fax: + 47 67 83 86 01 Email: petroleum@standa
[email protected] rd.no Website: www www.standard.no/petroleum .standard.no/petroleum
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
Edition 2, October 2012
Foreword
2
Introduction
2
1
Scope
3
2
Normative and informative references 2.1 Normative references 2.2 Informative references
3 3 3
3
Terms, definitions and abbreviations 3.1 Terms and definitions 3.2 Abbreviations
4 4 4
4
Qualification 4.1 General 4.2 Basis for qualification of steel foundries 4.3 General requirements 4.4 Manufacturing 4.5 Qualification based upon a test program
4 4 5 5 5 6
4.5.1
General
6
4.5.2
Qualification of the manufacturing process
6
4.5.3
Validity of qualification
6
4.5.4
Selection of material for testing
7
4.5.5
Extent of testing
7
4.5.6
Base material
7
4.5.7
Weldability
7
4.5.8
Qualification test record
7
5
Requirement to cast structural steel 5.1 Steel making process 5.2 Heat treatment
8 8 8
5.2.1
General
8
5.2.2
Heat treatment procedures
8
5.2.3 5.3 5.4
Post weld heat treatment (PWHT) Chemical composition Mechanical testing
8 8 9
5.4.1
General
9
5.4.2
Frequency of testing
10
5.4.3
Position of test specimens
10
5.4.4
Test methods
10
5.4.5 5.5
Mechanical properties Retesting and criteria for rejection
10 11
6
Non – destructive testing (NDT) 6.1 General 6.2 Surface requirements 6.3 Qualification of NDT personnel 6.4 Extent of testing 6.5 Test methods
11 11 11 11 12 12
6.5.1
Visual inspection
12
6.5.2
Magnetic particle testing
12
NORSOK standard
Page 1 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
Edition 2, October 2012
6.5.3
Radiographic testing
12
6.5.4 6.6
Ultrasonic testing Acceptance criteria
12 13
6.6.1
General
13
6.6.2
Visual examination
14
6.6.3
Radiographic testing
14
6.6.4
Ultrasonic testing
14
6.6.5
Magnetic particle testing
14
7
Repair 7.1 Repair by grinding 7.2 Repair by welding
15 15 15
8
Tolerances for dimensions and weight
15
9
Surface protection
15
10
Marking
16
11
Certificate
16
Foreword The NORSOK standards are developed by the Norwegian petroleum industry to ensure adequate safety, value adding and cost effectiveness for petroleum industry developments and operations. Furthermore, NORSOK standards are, as far as possible, intended to replace oil company specifications and serve as references in the authorities’ regulations. The NORSOK standards are normally based on recognised international standards, adding the provisions deemed necessary to fill the broad needs of the Norwegian petroleum industry. Where relevant, NORSOK standards will be used to provide the Norwegian industry input to the international standardisation process. Subject to development and publication of international standards, the relevant NORSOK standard will be withdrawn. The NORSOK standards are developed according to the consensus principle generally applicable for most standards work and according to established procedures defined in NORSOK A-001. The NORSOK standards are prepared and published with support by The Norwegian Oil Industry Association (OLF), The Federation of Norwegian Industry, Norwegian Shipowners’ Association and The Petroleum Safety Authority Norway. NORSOK standards are administered and published by Standards Norway.
Introduction This NORSOK standard is based on former company specifications and experience from deliveries and operation.
NORSOK standard
Page 2 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
1
Edition 2, October 2012
Scope
This NORSOK standard defines the requirements for qualification of foundries and the technical delivery requirements for cast structural steel for use in offshore structures where steel quality level I or II is required.
2
Normative and informative references
The following standards include provisions and guidelines which, through reference in this text, constitute provisions and guidelines of this NORSOK standard. Latest issue of the references shall be used unless otherwise agreed. Other recognized standards may be used provided it can be shown that they meet the requirements of the referenced standards.
2.1
Normative references
ASME V, Article 5, ASME V, Article 7, ASTM A609, ASTM A991, ASTM E112, ASTM E45, ASTM E125 – 80, ASTM E446, ASTM E186, ASTM E280, EN 287-1, EN 473/Nordtest/ASNT, EN 10204, EN 10225, ISO148, ISO 6892, ISO 8062, ISO 9001, ISO 10423, ISO 15607, ISO 15609-1, ISO 15614-1,
ISO/IEC 17025, MSS-SP 55, NORSOK M-101, Recommandation Technique No. 359-01 du Bureau de Normalisation des Industries de la Fonderie (BNIF),
2.2
Ultrasonic Examination Methods For Materials And Fabrication Magnetic Particle Examination Standard Practice For Castings, Carbon, Low-Alloy And Martensitic Stainless Steel, Ultrasonic Examination Thereof Standard Test Method for Conducting Temperature Uniformity Surveys of Furnaces Used to Heat treat Steel products Standard Test Method for Determining Average Grain Size Standard Test Methods for Determining the Inclusion Content of Steel Standard Reference Photographs For Magnetic Particle Indications On Ferrous Castings Reference Radiographs For Steel Castings Up To 51 mm In Thickness Reference Radiographs For Heavy-Walled (51 to 112 mm) Steel Castings Reference Radiographs For Heavy-Walled (112 to 305 mm) Steel Castings Qualification test of welders – Fusion welding – Part 1: Steels Qualification of NDT operators Metallic products – Types of inspection documents Weldable structural steels for fixed offshore structures – Technical delivery conditions Steel – Charpy impact test (V-notch) Metallic material – Tensile testing at ambient temperature Castings – System of dimensional tolerances and machining allowances Quality management systems – Requirements Petroleum and natural gas industries – Drilling and production equipment – Wellhead and Christmas tree equipment Specification and qualification of welding procedures for metallic materials – General rules Specification and qualification of welding procedures for metallic materials – Welding procedure specification – Part 1: Arc welding Specification and qualification of welding procedures for metallic materials – Welding procedure test – Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys General requirements for the competence of testing and calibration laboratories Visual Inspection Guide For Steel Castings Structural steel fabrication
Informative references
None
NORSOK standard
Page 3 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
3
Edition 2, October 2012
Terms, definitions and abbreviations
For the purposes of this NORSOK standard, the following terms, definitions and abbreviations apply.
3.1
Terms and definitions
3.1.1 can verbal form used for statements of possibility and capability, whether material, physical or casual 3.1.2 may verbal form used to indicate a course of action permissible within the limits of this NORSOK standard 3.1.3 shall verbal form used to indicate requirements strictly t o be followed in order to conform to this NORSOK standard and from which no deviation is permitted, unless accepted by all involved parties 3.1.4 should verbal form used to indicate that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required
3.2 ACCP AOD ASME ASNT ASTM BS CTOD EN FATT HAZ IEC IIW ISO MT NDT PWHT RT VAD VODC UT
Abbreviations ASNT Central Certification Program argon oxygen decarburisation American Society Mechanical Engineers Standard American Society for Non-destructive Testing American Society for Testing and Materials British Standard crack tip opening displacement European Standard fracture appearance transition temperatures heat affected zone International Electrotechnical Commisssion International Institute of Welding International Organization for Standardization magnetic particle testing non-destructive testing post weld heat treatment radiographic testing vacuum argon decarburisation vacuum oxygen decarburisation converter Ultrasonic testing
4
Qualification
4.1
General
The purchaser may accept the foundry’s qualification based on general information described in 4.2-4.4 combined with a verification or audit at the foundry. However, depending on the criticality and complexity of the casting and the experience of the foundry, the purchaser may require the foundry to perform a qualification as described in 4.5.
NORSOK standard
Page 4 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
4.2
Edition 2, October 2012
Basis for qualification of steel foundries
The basis for qualification is as follows: documented knowledge and previous experience with the material and the manufacturing; manufacturing facilities and equipment; established manufacturing procedures covering all important manufacturing steps from melting to finished products; manufacturers quality system, which shall fulfill the requirements related to product realization in ISO 9001; results of testing in compliance with this NORSOK standard.
Prior to qualification a complete report, with information and results of testing as required by this standard shall be available for review.
4.3
General requirements
The manufacturer shall have knowledge and experience within relevant metallurgical aspects of the applicable steel grades including welding, heat treatment parameters, etc. as applicable for his manufacturing process. Experience should be supported by statistical data or relevant test records for the size range to be qualified. The steel shall have been produced to manufacturing procedures and with equipment intended used for the actual manufacturing. Facilities and equipment shall be fit for purpose, regularly maintained and calibrated as required. The assessment shall concentrate on facilities and equipment for moulding, melting, refining, welding, heat treatment, etc. Foundries shall have heat treatment facilities on their own premises or such facilities shall be located in their close vicinity. If parts of the production are carried out at a sub-supplier, the manufacturer is responsible for ensuring that the sub-supplier meets the requirements of this standard for the manufacturing steps that he is performing.
4.4
Manufacturing
The manufacturer shall have a Manufacturing Summary for each production route. The Manufacturing Summary shall describe, step by step in a logical and correct sequence all important manufacturing activities with reference to detailed procedures. A short description and the main parameters for each activity shall be included. The production route shall be illustrated with a flow chart. The scope of the manufacturing summary shall be clearly defined:
name and address of manufacturer; grade of material; type and size range of products for which the manufacturing summary applies; identification of the manufacturing process.
The manufacturing summary shall include procedures for
moulding method, type of sand, binding agent and method of casting, melting and refining processes, heat treatment, including loading temperature, heating rate, holding temperature (range) and time, loading and stacking of components in furnace, type and identification of furnace(s), maximum operation temperature for furnace(s), temperature control and calibration of furnace(s), cooling facilities and max. time from furnace to quenching bath (if relevant), sketch of heat treatment facilities/furnace which also shall show location of pyrometers and/or thermocouples in the furnace(s) and on the component(s).
NORSOK standard
Page 5 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
Edition 2, October 2012
blasting/cleaning equipment, incl. type of grit, repair welding, PWHT (if applicable), NDT and inspection, material testing. Type of tests and test sampling, design and position of test coupons.
If the manufacturer has different plants or different production routes for a product, separate documentation is required for each of these. If essential parts of the work such as e.g. heat treatment are subcontracted, this shall be identified in the documentation. Whenever a change is made in the equipment or procedures, the documentation shall be updated accordingly. The casting shall not be subject to any plastic deformation during manufacturing including handling at high temperatures.
4.5
Qualification based upon a test program
4.5.1
General
For critical structural castings or castings intended for welding, base material and weldability data shall be required documented according to 4.5.2 to 4.5.8. 4.5.2
Qualification of the manufacturing process
The manufacturing process as described in the manufacturing summary shall be qualified by testing of actual products or of test blocks, if accepted by the purchaser, to
demonstrate that the proposed manufacturing route and production parameters results in products meeting specified requirements, verify that the proposed production test sampling gives results which are representative of the properties in the actual components which they represent.
4.5.3 4.5.3.1
Validity of qualification General
The qualification shall be repeated if there are changes in the production route, the manufacturing procedures or the specified composition or properties of the products which exceeds the limits given below. 4.5.3.2
Plant and location
If production is carried out at different plants/locations, a separate qualification is required for each plant. This applies also for change of subcontractors for essential operations as e.g. heat treatment, etc. 4.5.3.3
Thickness limitations
The maximum thickness qualified is the thickness of the tested product or test block plus 25 %. 4.5.3.4
Material grade
A change from one steel grade to a higher grade requires requalification. 4.5.3.5
Type of melting and refining equipment
A change of the melting/refining process requires a requalification. 4.5.3.6
Manufacturing equipment
A major change of manufacturing equipment requires requalification, unless the new equipment can be regarded as comparable to the old one with respect to its influence on the product properties. This applies also if the manufacturer has several alternative manufacturing routes for a product.
NORSOK standard
Page 6 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122 4.5.3.7
Edition 2, October 2012
Heat treatment
A change of heat treatment method, (e.g. a change from normalising to quenching and tempering) will require requalification. This also includes change in PWHT operations, when applicable. 4.5.4
Selection of material for testing
Selection of components or test blocks for testing and positioning of test samples shall be agreed between purchaser and the manufacturer. 4.5.5
Extent of testing
Testing for qualification shall comprise
production testing with test sampling as specified in this NORSOK standard, additional testing for qualification as required by this NORSOK standard, non-destructive testing as specified in this NORSOK standard.
4.5.6 4.5.6.1
Base material General
The material used for the examinations to document properties shall be representative, implying that the steel making process, casting methods and heat treatment condition shall be equal to that proposed for the actual delivery. The section thicknesses shall be representative for the thinnest and thickest portion in the casting for the actual delivery. 4.5.6.2
Chemical composition and mechanical properties
The chemical composition and mechanical properties shall be as per clause 5. 4.5.6.3
Charpy V-notch impact test transition curves
Charpy V-notch impact test transition curves (÷ 80 °C, ÷ 60 °C, ÷ 40 °C and ÷ 20 °C) shall be made for both the thinnest and thickest material section. The position and number of the test specimens shall be as specified in 5.4.3. Both the energy absorption (J) and the FATT, defined as 50 % crystallinity, shall be reported. 4.5.6.4
Micrographic examinations
The base material microstructure shall be documented by micrographs at magnification 500 X from subsurface, 1/4 thickness and 1/2 thickness position. The type of structure, grain size and inclusion level shall be reported. Examination shall be carried out according to ASTM E112 and ASTM E45. 4.5.7
Weldability
Weldability data are required for castings with a weld bevel thickness above 25 mm. The thickness to be used for the weldability test shall be agreed, but shall not to less than 10 % below the weld bevel thickness to be delivered The documentation of the weldability shall be in accordance with EN 10225, Annex E. The heat input shall be 3,5 ± 0,2 kJ/mm (EN 10225, Table E.3). For weld bevel thicknesses above 50 mm the testing shall be carried out both in the as welded and PWHT condition. CTOD testing is required for weld bevel thickness above 50 mm and shall meet a requirement of minimum 0,25 mm (as-welded) and 0,20 mm (PWHT), at ÷ 10 °C unless a lower value has been accepted by the purchaser. CTOD testing is limited to only grain-coarsened HAZ. 4.5.8
Qualification test record
The manufacturer shall present a qualification test record containing results of all required tests as well as details about test sampling and test procedures.
NORSOK standard
Page 7 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
5
Requirement to cast structural steel
5.1
Steel making process
Edition 2, October 2012
The steel shall be made by basic oxygen or electric arc furnace process and shall be fully killed and fine grain treated. A further treatment by ladle desulphurization and secondary refining using AOD/ VODC/ VAD or equal, shall be performed to secure a base material with very close controlled chemistry and low levels of elements like phosphorous, sulphur, oxygen and hydrogen.
5.2
Heat treatment
5.2.1
General
All castings shall be delivered in homogenised, normalised and stress relieved condition, or in homogenised, quenched and tempered condition, also including any post weld heat treatment after repair welding. 5.2.2
Heat treatment procedures
All heat treatments shall be carried out according to an accepted procedure containing at least the following information:
description of furnaces and quenching facilities; location and support of the castings in the furnace; locations and number of thermocouples; all temperature cycles.
The heat treatment variables shall be selected to promote uniform microstructure, correct mechanical properties for the different section thicknesses and to reduce residual stresses. Heat treatment temperatures shall be measured and recorded by means of thermocouples attached to the castings. The temperature in the furnace at the time of loading the castings shall not exceed 200 °C. The heating and cooling rates for temperatures above 300 °C shall not exceed 70 °C and 50 °C per hour respectively except for quenching. Below 300 °C the castings may be cooled in still air. The heat treatment furnaces shall be calibrated according to ASTM A991 or ISO 10423, Annex M. 5.2.3
Post weld heat treatment (PWHT)
PWHT shall be carried out after any repair welding. All PWHT shall be carried out in a closed furnace. The soaking temperature shall be as qualified during the repair welding procedure. The soaking time shall be minimum 2 min/mm of the thickest wall at the actual weld repair location.
5.3
Chemical composition
Chemical composition for the three cast steel grades are given in Table 1. The values apply to both ladle and product analysis. Any modification from Table 1 shall be agreed in each case. Ladle analysis shall be performed for each heat and product analysis performed for each casting.
NORSOK standard
Page 8 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
Edition 2, October 2012
Table 1 – Chemical composition Steel Grade C Si Mn S P Cr Ni Mo Al N Cu b) Nb b) V Ti Sb Sn Pb As Bi B a) Pcm a) CE
310 0,14 0,60 1,60 0,008 0,012 0,20 1,10 0,08 0,05 0,010 0,25 0,03 0,05 0,04 0,01 0,015 0,005 0,02 0.005 0,0010 0,24 0,41
420 0,14 0,60 1,60 0,008 0,012 0,25 1,10 0,30 0,05 0,010 0,25 0,03 0,05 0,04 0,01 0,015 0,005 0,02 0,005 0,0010 0,26 0,48
460 0,14 0,50 1,60 0,005 0,012 1,3 2,7 0,55 0,05 0,010 0,25 0,03 0,05 0,04 0,01 0,015 0,005 0,02 0,005 0,0010 0,28 0,55
All values are maximum values unless a range is given, all in weight percent. a)
Pcm C
CE C
Si 30
Mn 6
Mn Cu Cr Ni Mo V 5B 20 60 15 10
Cr Mo V 5
Ni Cu 15
b)
Nb V 0,05% 5.4 5.4.1
Mechanical testing General
All mechanical testing shall be carried out in the final delivery condition (including PWHT). The test blocks shall not be removed from the castings until all quality heat treatments have been carried out. It is acceptable that the test blocks are given a simulated PWHT. All mechanical testing for certification shall be performed by a laboratory that complies with ISO/IEC 17025 or an accredited laboratory
NORSOK standard
Page 9 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122 5.4.2
Edition 2, October 2012
Frequency of testing
Product testing shall be carried out for each cast item. Other frequencies of mechanical testing might be agreed with the purchaser in case of large series of castings or weight less than 1 ton. The number of test blocks shall be: A. Integral test block(s): Weight of castings “G” (tonnes) G 50 mm
- Mid thickness (T/2) - Sub surface (2 mm below surface) and T/3
Test methods
The tensile testing shall be carried out according to ISO 6892. The Charpy V-notch testing shall be carried out according to ISO 148. The longitudinal axis of the specimen shall be parallel to the cast surface with the notch perpendicular to the same. 5.4.5
Mechanical properties
Requirements for mechanical properties are given in Table 2. Table 2 – Mechanical properties Steel grade
310 420 460
Yield strength Re min* MPa 310 420 460
Tensile strength Rm min MPa 450 540 560
Elongation A5 min % 20 20 18
Reduction of area Z min % 50 40 40
Impact test KV min J average/single 36/27 42/35 42/35
KV test temp. o C ÷40 ÷40 ÷40
Ratio Re /Rm maximum 0,85 0,90 0,90
For section thicknesses above 100 mm, lower values for Re and Rm may be agreed. * Re = ReH or Rp 0,2
NORSOK standard
Page 10 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
5.5
Edition 2, October 2012
Retesting and criteria for rejection
If one or more of the results fails to meet the requirements, the manufacturer may carry out double set of additional tests, preferably from the same test coupon and position. All results from retest shall meet the requirements. If retesting fails, the casting will be rejected. However the manufacturer may choose to carry out a reheat treatment once followed by full set of mechanical testing. If any results still are not acceptable, the casting or lot will be rejected.
6
Non – destructive testing (NDT)
6.1
General
All NDT shall be carried out in accordance with the established procedures. The NDT reports shall show examined areas, size and nature of defects and reportable indications.
6.2
Surface requirements
All surfaces shall be free from irregularities which may interfere with the performance of the examinations. The surface of the castings shall be examined visually and shall be free of adhering sand, scale, cracks and hot tears. Other surface discontinuities shall meet the requirements specified for MT. Surface roughness shall as a minimum be as follows (see Recommandation Technique No. 359-01 du Bureau de Normalisation des Industries de la Fonderie (BNIF)):
4S1 on surfaces subject to UT with normal probes; 3S2 on surfaces subject to UT with angle probes; 3S2 on transition zones/fillets surfaces subject to MT; 4S1 on general surfaces subject to MT and Visual inspection; 3S1 on surfaces subject to RT only.
When surfaces are machined the roughness shall as a minimum be as follows (see BS 2634-1):
6.3
Ra 12 m on surfaces subject UT with normal probes; Ra 6 m on surfaces subject UT with angel probes; Ra 12 m on general surfaces subject to MT and visual inspection.
Qualification of NDT personnel
All NDT personnel shall be qualified according to EN 473/Nordtest level II in product sector (c) or an industry sector containing product sector (c) ASNT ACCP level 2 accredited NDT. Personnel performing RT exposures only, may, however, be qualified to level I. Personnel qualified to level III, shall be r esponsible for all NDT activities. ASNT-TC-1A level III personnel shall hold valid ASNT-TC-1A level III Certificate (i.e. Management appointed level III is not accepted). Contractor shall keep an updated list of all NDT personnel engaged in the work, with reference to possessed certificates and expiry dates. This list shall be made available to Purchaser on request.
NORSOK standard
Page 11 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
6.4
Edition 2, October 2012
Extent of testing
The extent of NDT shall be as per Table 3. Table 3 - Extent of NDT Methods
Areas and volume to be examined
Visual Surface from inside and outside. examinations Magnetic particle Surface from inside and outside. testing Excavated grooves before start of repair welding. Radiographic Weld end zones. testing Area 3 x thickness of the edge, or minimum 100 mm Questionable indications detected by ultrasonic testing Ultrasonic testing Normal probes. Volumetric testing (from all accessible inside and outside Angle probes. Areas where the angles between front and back surfaces of the casting exceed 15 (non-parallel) Angle probes. Areas where loss of back wall echo occurs. Angle probes. Indications from the testing with normal probes. Repaired areas where the defects were detected by radiography or ultrasonic testing. NOTE 1
NOTE 2
6.5 6.5.1
Extent of NDT % 100 100
ime for examination NOTE 1 F F
100 100 NOTE 2 100 100
100
100 100 100
F
F means that the NDT shall be carried out in the final repair welded and PWHT condition. Otherwise, the NDT may be carried out before the final repair welding and PWHT. 100 % radiography of weld end zones may be deleted provided ultrasonic testing (UT) is carried out in accordance with NORSOK M-101 and the acceptance criteria as specified in 9.8/Table 5 Inspection Category A+B.
Test methods Visual inspection
Visual inspection shall be in accordance with MSS SP-55 6.5.2
Magnetic particle testing
Magnetic particle testing shall be carried out according to ASME Section V, Article 7. An NDT procedure shall be prepared. The procedure shall show the acceptance criteria. 6.5.3
Radiographic testing
Radiographic testing shall be carried out in accordance with ASME Section V, Article 2. A written procedure shall be prepared as specified in T-221.1. 6.5.4 6.5.4.1
Ultrasonic testing Procedures
Ultrasonic testing shall be carried out in accordance with ASME Section V, Article 5, using normal probes and angle probes.
NORSOK standard
Page 12 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122 6.5.4.2
Edition 2, October 2012
Procedures
The ultrasonic testing procedures shall additionally include at least the following information: sensitivity setting; typical sketches of section (with dimensions) to be examined which clearly show scanning pattern and probes to be used; acceptance criteria; reporting and identification system.
6.5.4.3
Probes
The frequency value shall be selected to suit the test and shall be within the range 0.5 MHz to 5 MHz. Higher frequency can be used for testing wall thicknesses of less than 20 mm or areas close to the surface. For the detection of near-surface discontinuities, the use of dual-element and/or angle probes shall be used. The probes for ultrasonic testing shall be selected in accordance with Table 4. Table 4- Probes for ultrasonic testing Section thickness < 100 mm > 100 mm NOTE 1 NOTE 2 NOTE 3
6.5.4.4
Normal probes
Angle probes
4 MHz, crystal size diameter 10 mm to 24 mm 2 Mhz, crystal size diameter 10 mm to 24 mm
2 Mhz to 4 Mhz, 45 to 70 crystal size, approximately 8 mm x 9 mm 2 Mhz to 4 MHz, 45 to 70 crystal size, approximately 20 mm x 22 mm
Crystal size shall be selected to give optimum coverage and coupling to test surface. Twin crystal probes shall be used for evaluation of indications close to the surface. All available probes shall be used for assessment of indications.
Calibration blocks
The flat bottom holes in the reference blocks in ASTM A609, Figure 1, shall have a diameter equal to 3 mm for sensitivity setting for normal probes. One additional reference block is required having metal distance equal to 10 mm for assessment of indications close to the surface. 6.5.4.5
Ultrasonic attenuation
The ultrasonic attenuation in the casting shall be checked at different typical locations of the casting. The difference in attenuation shall be taken into consideration during the testing.
6.6 6.6.1
Acceptance criteria General
Contractor shall review the defined acceptance criteria in 6.6.2, 6.6.3 and 6.6.4 and secure that these meet the design requirements for the cast steel materials. Manufacturer shall be informed if more stringent acceptance criteria have to be applied. Revised acceptance criteria shall be implemented on drawings, NDT procedures and NDT reports. The castings are divided in Zone 1, 2 and 3 as follows, unless otherwise shown on drawings: Zone 1: Zone 2: Zone 3:
0 mm to 30 mm from all finished surfaces and all critical zones independent of thickness Depths greater than 30 mm from all finished surfaces. Weld end zones: Full thickness of end (preparation) for a distance of 3T or minimum 100 mm from the (preparation) end.
NORSOK standard
Page 13 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122 6.6.2
Edition 2, October 2012
Visual examination
All surfaces shall show evidence of good workmanship and satisfy the following:
surface requirements as per 6.2; visual appearance shall also satisfy 6.6.5; MSS-SP-055.
6.6.3
Radiographic testing
Acceptance criteria related to type of discontinuity and zones are given in Table 5 Table 5 – Acceptance criteria for radiographic testing Zone
Type of discontinuity Cracks Gas porosity Inclusions Shrinkage Cracks Gas porosity Inclusions Shrinkage Cracks Gas porosity Inclusions Shrinkage
1
2
3
6.6.4
Acceptance standard Not acceptable ASTM E186, ASTM E280, ASTM E446, level A2 ASTM E186, ASTM E280, ASTM E446, level B2 ASTM E186, ASTM E280, ASTM E446, level C2 Not acceptable ASTM E186, ASTM E280, ASTM E446, level A4 ASTM E186, ASTM E280, ASTM E446, level B4 ASTM E186, ASTM E280, ASTM E446, level C4 Not acceptable Shall meet the requirements of NORSOK M 101: Inspection category A + B Section 9.8, Table 6. Shrinkage: ASTM E186, ASTM E280, ASTM E446, level C1
Ultrasonic testing
Acceptance criteria for ultrasonic testing are given below: Zone 1
ASTM A609, Table 2 - Level 1 Linear indications are not acceptable.
Zone 2
ASTM A609, Table 2 - Level 3 Linear indications are not acceptable.
Zone 3
Indications shall meet the requirements of NORSOK M 101 - Inspection category A + B Table 7.
6.6.5
Magnetic particle testing
Acceptance criteria for magnetic particle testing are given in Table 6 Table 6 – Acceptance criteria for magnetic particle testing Type of indications linear shrinkage inclusions chills and chaplets porosity
NORSOK standard
Acceptance standard not acceptable ASTM E125, level 2 ASTM E125, level 3 ASTM E125, level 1 ASTM E125, level 1
Page 14 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
7
Repair
7.1
Repair by grinding
Edition 2, October 2012
Repair by arc gouging and grinding may be carried out to a depth of maximum 10 % of the wall thickness (at the location of the defect) or maximum 15 mm, whichever is less. It is a provision that the design wall thickness is maintained. Arc-air gouged areas shall be ground. The ground area shall be 100 % magnetic particle tested to ensure complete elimination of the defective material. All grinding shall be carried out in a way that ensures smooth transitions.
7.2
Repair by welding
Defects shall be repaired by welding if they are deeper than 15 mm or 10 % of the wall thickness. All repair welds shall be recorded. The maximum extent of repair welding shall not exceed 20 % of the total surface area unless otherwise agreed with the purchaser. The excavations shall be suitably shaped to allow good access for welding. The groove shall be ground smooth and be free from dirt, grease, oil, etc. Welding consumable of low hydrogen content (maximum 5 ml/H DM pr. 100 g, IIW-method) shall be used for repair welding. The welding consumable shall be handled according to the consumable manufacturer's recommendations. Repair welding procedures shall be established and qualified according to ISO 15607, ISO 15609-1 and ISO 15614-1, with the following additional requirements. The repair welding procedure shall be qualified on the same grade of material as the delivered component:
Charpy V-notch impact tests with notch locations in weld metal, fusion line and heat affected zone + 2 mm and + 5 mm from fusion line, respectively. Test results shall meet the requirements specified for the parent metal; macro section; hardness values shall not exceed 350 HV10.
Welders shall be qualified according to EN 287-1. Castings repaired by welding shall be post weld heat treated at a temperature at least 15 °C below the tempering temperature. On completion of heat treatment the weld repairs and adjacent material shall be ground smooth. All weld repairs shall be magnetic particle tested and major repairs shall additionally be ultrasonic (or radiographic) tested. Weld repairs shall meet the quality level designated for that particular zone of the casting. The foundry shall maintain records of repair welding, subsequent heat treatment and inspections traceable to each casting repaired.
8
Tolerances for dimensions and weight
Dimensions and required tolerances shall be as given on the relevant drawing of the casting or other information supplied. If nothing is specified, ISO 8062, Grade CT, 13 shall apply. The weight tolerances shall be within agreement with the purchaser.
9
Surface protection
Castings shall before delivery, be degreased, shot blasted to bright metal and protected by a shop primer with a dry film thickness of approximately 20 μm. All sharp edges shall be rounded and smoothed by grinding to a minimum radius of 2 mm to assure full film thickness on all edges. Machined surfaces shall be protected by a rust protection coating (water soluble Tectyl or equivalent).
NORSOK standard
Page 15 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
NORSOK standard M-122
10
Edition 2, October 2012
Marking
Castings shall be marked for identification against a certificate. The marking shall include Contractor’s identification and heat number. All markings shall be carried out by die stamping or as cast in marks, and be framed by white painting. The letters used for the stamping should be 15 mm in height.
11
Certificate
Certificate according to 3.1 (see EN 10204) is required. The certificate shall contain all relevant information including, but not restricted to the following:
purchaser’s name and order number; delivery condition; heat number/casting number; description of product, dimension and weight; yield strength, tensile strength, elongation and reduction of area; Charpy V-notch values and test temperature; chemical composition, carbon equivalent/Pcm; visual inspection and NDT, or reference to separate reports; weld repairs, or reference to separate reports.
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P NORSOK standard
Page 16 of 16
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
3 2 6 0 4 1 0 2 s i l u o b a t S + s o i t a n g I r o f S A e n i l n O d r a d n a t S y b d e d i v o r P
