moduk def stan 02-747 part 2

Ministry of DefenceDefence Standard 02-747 (NES 747)

Issue 1 Publication Date 01 April 2000

Incorporating NES 747 Part 2 Category 2

Issue 3 Publication Date January 1995

Requirements For Nickel AluminiumBronze Castings And Ingots

Part 2Nickel Aluminium Bronze

Naval Alloy Ingots AndSand Castings With Welding

Permitted To The Wetted Surface

DStan

DStan is now the publishing authority for all Maritime Standards (formerly NESs). Any reference to any other publishing authority throughout this standard should be ignored. Any queries regarding this or any other Defence Standard should be referred to the DStan Helpdesk as detailed at the back of this document.

AMENDMENT RECORD

Amd No Date Text Affected Signature and Date

REVISION NOTE

This standard is raised to Issue 1 to update its content.

HISTORICAL RECORD

This standard supersedes the following:

Naval Engineering Standard (NES) 747 Part 2 Issue 3 dated January 1995.

Ministry of Defence

Naval Engineering Standard

NES 747 Part 2 Issue 3 (Reformatted) January 1995

REQUIREMENTS FORNICKEL ALUMINIUM BRONZE CASTINGS AND INGOTS

PART 2

NICKEL ALUMINIUM BRONZE NAVAL ALLOY INGOTS ANDSAND CASTINGS WITH WELDING PERMITTED TO

THE WETTED SURFACE

This NES Supersedes

NES 747 PART 2 ISSUE 2

Record of Amendments

AMDT INSERTED BY DATE

1

2

3

4

5

6

7

8

9

10

i

NAVAL ENGINEERING STANDARD 747

REQUIREMENTS FOR NICKEL ALUMINIUM BRONZE

CASTINGS AND INGOTS

PART 2

ISSUE 3 (REFORMATTED)

NICKEL ALUMINIUM BRONZE NAVAL ALLOY INGOTS AND SAND

CASTINGS WITH WELDING PERMITTED TO THE WETTED SURFACE

The issue and use of this Standard

is authorized for use in MOD contracts

by MOD(PE) Sea Systems and

the Naval Support Command

ECROWN COPYRIGHT

Published by:

Director of Naval ArchitectureProcurement Executive, Ministry of DefenceSea Systems, Foxhill, Bath BA1 5AB

NES 747Part 2

Issue 3 (Reformatted)

iii

SCOPE

1. This NES states the requirements for the physical characteristics, test methods andacceptance standards of cast nickel aluminium bronze naval alloy ingots and sand castingswith welding permitted to the wetted surface. (See Section 1. for applicability.)

Submarines

2. This NES does not cover the use of the castings for first level systems and castings that maycome into contact with sea water except as indicated in Clause 1.a.

NES 747Part 2Issue 3 (Reformatted)

iv

NES 747Part 2


v

FOREWORD

Sponsorship

1. ThisNaval Engineering Standard (NES) is sponsored by theProcurement Executive, Ministryof Defence, Director Naval Architecture (DNA), Section NA 115.

2. This NES comprises:

Requirements for Nickel Aluminium Bronze (NAB) Castings and Ingots.

Part 1 Nickel Aluminium Bronze Naval Alloy Centrifugally Cast

Part 2 Nickel Aluminium Bronze Naval Alloy Ingots and Sand Castings with WeldingPermitted to the Wetted Surface

Part 3 Nickel Aluminium Bronze Commercial Alloy Sand Castings and Ingots

Part 4 Nickel Aluminium Bronze Naval Alloy Sand Castings with Welding Restricted to theNon-Wetted Surface (Class I and II Castings only)

Part 5 Guide to the Design and Manufacture of Nickel Aluminium Bronze Sand Castings

3. If it is found to be unsuitable for any particular requirement the Sponsor is to be informed inwriting of the circumstances with a copy to Director Naval Architecture (DNA),Section NA 145.

4. Any user of this NES either within MOD or in industry may propose an amendment to it.Proposals for amendments which are:

a. not directly applicable to a particular contract are to be made to the Sponsor of theNES;

b. directly applicable to a particular contract are to be dealt with using existingdepartmental procedures or as specified in the contract.

5. No alteration is to be made to this NES except by the issue of an authorized amendment.

6. Unless otherwise stated, reference in this NES to approval, approved, authorized or similarterms means by the Ministry of Defence in writing.

7. Any significant amendments that may be made to this NES at a later date will be indicatedby a vertical sideline. Deletions will be indicated by 000 appearing at the end of the lineinterval.

8. This NES has been reissued to reflect changes in technical requirements.


vi

Conditions of Release

General

9. This Naval Engineering Standard (NES) has been prepared for the use of the Crown and ofits contractors in the execution of contracts for the Crown. The Crown hereby excludes allliability (other than liability for death or personal injury) whatsoever and howsoever arising(including but without limitation, negligence on the part of the Crown, its servants or agents)for any loss or damage however caused where the NES is used for any other purpose.

10. This document is Crown Copyright and the information herein may be subject to Crown orthird party rights. It is not to be released, reproduced or published without written permissionof the MOD.

11. The Crown reserves the right to amend or modify the contents of this NES without consultingor informing any holder.

MOD Tender or Contract Process

12. ThisNES is the property of the Crown and unless otherwise authorized in writing by theMODmust be returned on completion of the contract, or submission of the tender, in connectionwith which it is issued.

13. When this NES is used in connection with aMOD tender or contract, the user is to ensure thathe is in possession of the appropriate version of each document, including related documents,relevant to each particular tender or contract. Enquiries in this connection may be made ofthe local MOD(PE) Quality Assurance Representative or the Authority named in the tenderor contract.

14. When NES are incorporated into MOD contracts, users are responsible for their correctapplication and for complying with contracts and any other statutory requirements.Compliance with an NES does not of itself confer immunity from legal obligations.

Related Documents

15. In the tender and procurement processes the related documents listed in each section andAnnex A can be obtained as follows:

a. British Standards British Standards Institution,389 Chiswick High Road,London W4 4AL

b. Defence Standards Directorate of Standardization and Safety Policy,Stan 1, Kentigern House, 65 Brown Street,Glasgow G2 8EX

c. Naval Engineering Standards CSE3a, CSE Llangennech, Llanelli,Dyfed SA14 8YP

d. Other documents Tender or Contract Sponsor to advise.

Note: Tender or Contract Sponsor can advise in cases of difficulty.

16. All applications to Ministry Establishments for related documents are to quote the relevantMOD Invitation to Tender or Contract Number and date, together with the sponsoringDirectorate and the Tender or Contract Sponsor.

17. Prime Contractors are responsible for supplying their subcontractors with relevantdocumentation, including specifications, standards and drawings.

NES 747Part 2


vii

Health and Safety

Warning

18. ThisNESmay call for the use of processes, substances and/or procedures thatmay be injuriousto health if adequate precautions are not taken. It refers only to technical suitability and inno way absolves either the supplier or the user from statutory obligations relating to healthand safety at any stage of manufacture or use. Where attention is drawn to hazards, thosequoted may not necessarily be exhaustive.


viii

NES 747Part 2


ix

CONTENTSPage No

TITLE PAGE i. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SCOPE iii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Submarines iii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FOREWORD v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sponsorship v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Conditions of Release vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MOD Tender or Contract Process vi. . . . . . . . . . . . . . . . . . . . . . . . . .

Related Documents vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Health and Safety vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Warning vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTENTS ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 1. APPLICABILITY 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 2. PHYSICAL CHARACTERISTICS 2.1. . . . . . . . . . . . .2.1 Ingots 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.2 Ingot Analysis 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TABLE 2.1 INGOTS—CHEMICALCOMPOSITION 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3 Castings 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.4 Casting Analysis 2.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.5 Quality of Material 2.2. . . . . . . . . . . . . . . . . . . . . . . . . . .

TABLE 2.2 CASTINGS—CHEMICALCOMPOSITION 2.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 3. MECHANICAL PROPERTIES 3.1. . . . . . . . . . . . . . . .TABLE 3.1 PROPERTIES 3.1. . . . . . . . . . . . . . . . . . . .

SECTION 4. HEAT TREATMENT 4.1. . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 5. CLASSIFICATION 5.1. . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 6. QUALITY ASSURANCE DOCUMENTATION 6.1. . .6.1 Ingots 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.2 Castings 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


x

SECTION 7. TEST METHODS 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .7.1 Destructive Tests 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.1.1 Analysis 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.2 Mechanical Tests 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.3 Retests 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.4 Non-Destructive Tests 7.1. . . . . . . . . . . . . . . . . . . . . . . . .7.5 Dimensional Check 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . .7.6 Visual-Optical 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.7 Liquid-Penetrant 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .7.8 Radiographic/Ultrasonic Examination 7.1. . . . . . . . . . .7.9 Radiography 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.10 Radiographic Examination of Non-Designated

Regions on a Sample Basis 7.2. . . . . . . . . . . . . . . . . . . . .7.11 Ultrasonic Examination 7.2. . . . . . . . . . . . . . . . . . . . . . .7.12 Pressure Tests 7.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 8. ACCEPTANCE STANDARDS 8.1. . . . . . . . . . . . . . . . .8.1 Destructive Examination Standards 8.1. . . . . . . . . . . . .8.1.1 Analysis 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.2 Mechanical Tests 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.3 Retests 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.4 Non-Destructive Examination Standards 8.1. . . . . . . .8.4.1 Visual-Optical 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.4.2 Liquid-Penetrant 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .8.5 Radiography 8.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.6 Ultrasonics 8.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.7 Pressure Tests 8.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 9. DEFECTS AND RECTIFICATION OF DEFECTS 9.19.1 Defects 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.2 Rectification of Dimensional Defects by Weld

Deposition 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.3 Rectification of Surface Defects by Blending 9.1. . . . . .9.4 Rectification of Surface and Sub-Surface Defects

by Welding 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.5 Limits on Individual Sub-Surface Repairs 9.2. . . . . . .9.6 Limits on Combined Weld Repairs 9.2. . . . . . . . . . . . . .9.7 Rectification of Defects 9.2. . . . . . . . . . . . . . . . . . . . . . . .9.8 Impregnation 9.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.9 Special Repairs 9.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 10. IDENTIFICATION OF INGOTS AND CASTINGS 10.110.1 Ingots 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.2 Castings 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 11. PACKAGING 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ANNEX A. RELATED DOCUMENTS A.1. . . . . . . . . . . . . . . . . . . .

ANNEX B. DEFINITIONS AND ABBREVIATIONS B.1. . . . . . . .

ANNEX C. PROCUREMENT CHECK LIST C.1. . . . . . . . . . . . . . .

NES 747Part 2


1.1

1. APPLICABILITY

a. This NES may be used for:

(1) Propellers.

(2) Class I and Class II castings which will not come into contact with seawater.

(3) Large/complex Class I and Class II castings which may come into contactwith sea water providing that MOD contractual approval is granted.

(4) Class III castings in accordance with NES 863.


1.2

NES 747Part 2


2.1

2. PHYSICAL CHARACTERISTICS

2.1 Ingots

a. Ingots for casting stock are to be cast from virgin metals as follows:

Nickel — to the chemical composition requirements of BS 375:Grade R99.9

Iron — Iron of high purity, 99.5% w/w, with a carbon content ofless than 0.05% w/w.

NOTE: ‘Swedish-Iron’ Nails have been found to meet the required purity.

Aluminium — commercially very pure Grade 99.90% w/w

Copper — to BS 6017—Cu−Cath−2 or Cu−ETP−2

Manganese — high purity electrolytic grade.

2.2 Ingot Analysis

a. Ingots analysis is to conform to the chemical composition in TABLE 2.1.

ElementPer Cent By Weight

ElementNot Less Than Not More Than

Aluminium 8.9 9.6

Iron* 4.0 5.0

Nickel* 4.5 5.5

Manganese 1.0 1.4

Copper (by difference) Remainder

Impurities

Zinc − 0.05

Lead − 0.01

Tin − 0.05

Silicon − 0.05

Magnesium − 0.05

Chromium − 0.01

Total Impurities − 0.20

* Nickel must exceed ironTABLE 2.1 INGOTS—CHEMICAL COMPOSITION

2.3 Castings

a. Casting are to be made from ingots and approved scrap (see Clause B.1).

NOTES: 1. Contamination by graphite can be prevented by coating cruciblesand ladles with an alumina wash. The product Alumina Cementpure Grade 961, marketed by Morgan Refractories, Neston Wirrall,Cheshire, or equivalent, has been found suitable.

2. All ingots used are to be stamped, embossed or have a label affixedwith a unique cast number. Any ingots, on which the stamping orembossing is illegible, or the label has been removed/fallen off, arenot to be used.


2.2

2.4 Casting Analysis

a. Casting Analysis is to conform to the chemical composition in TABLE 2.2.

2.5 Quality of Material

a. Only the manufacturer’s own approved scrap complying with Clause B.1 maybe included in the cast. No other scrap is permitted. Following acceptance of theanalysis from the melt, no further additions are permitted prior to pouring intothe mould.

ElementPer Cent By Weight

ElementNot Less Than Not More Than

Aluminium 8.8 9.5

Iron* 4.0 5.0

Nickel* 4.5 5.5

Manganese 0.75 1.3

Copper (by difference) Remainder

Impurities

Zinc − 0.05

Lead − 0.01

Tin − 0.05

Silicon − 0.10

Magnesium − 0.05

Chromium − 0.01

Total Impurities − 0.25

* Nickel content is to be greater than the iron contentTABLE 2.2 CASTINGS—CHEMICAL COMPOSITION

NES 747Part 2


3.1

3. MECHANICAL PROPERTIES

a. At room temperature the mechanical properties of test pieces, as specified inClause 7.2a., are to be as detailed in TABLE 3.1.

Tensile Strength (UTS) 0.2% Proof Stress(0.2% PS)

Elongation on 5.65Gauge Length

So

N/mm2 N/mm2 Per Cent

Min Min Min

620 250 15

TABLE 3.1 PROPERTIES


3.2

NES 747Part 2


4.1

4. HEAT TREATMENT

a. Prior to heat treatment the castings are to have been subjected to anon-destructive examination in accordance with the requirements ofClauses 7.5a. to 7.11a. inclusive and are to have met the necessary acceptancestandards. Weld repair of any defective areas will be carried out prior to heattreatment. In the event that further weld repair is required after heattreatment, the casting is to be heat treated for a second time following thesecond repair. No further heat treatments are permitted.

b. All castings and associated mechanical test pieces are to be heat treated at675° C ± 15°C for a minimum period of six hours. The castings are to besupported as necessary during the heat treatment to prevent excessivedistortion. The furnace temperature must not exceed 300° C when loading thecastings or test pieces. After a minimum of six hours at 675° C ± 15°C thecastings and test pieces are to be removed from the furnace and cooled to roomtemperature in still air. Heat treatment of test pieces may be carried outseparately from the castings they represent.

c. Only furnaces validated and approved in accordance with NES 746 are to beused for the heat treatment of castings and test pieces.


4.2

NES 747Part 2


5.1

5. CLASSIFICATION

a. The classification of castings is to be in accordance with NES 863.


5.2

NES 747Part 2


6.1

6. QUALITY ASSURANCE DOCUMENTATION

6.1 Ingots

a. Each consignment of ingots is to be accompanied by Quality AssuranceDocumentation providing the results of themelt control analysis and the resultsof analysis of a sample piece taken from an ingot within the batch.

6.2 Castings

a. Each consignment of castings is to be accompanied by Quality AssuranceDocumentation giving the actual results of the tests required in Section 7.together with a certificate of compliance with the acceptance standards detailedin Section 8.


6.2

NES 747Part 2


7.1

7. TEST METHODS

7.1 Destructive Tests

7.1.1 Analysis

a. In addition to the normal melt control analysis, a full chemical analysis is to bemade from a sample piece taken from each cast for ingots and for castings.

7.2 Mechanical Tests

a. Tensile tests in accordance with BS EN 10002 are to be made on a heat treatedtest sample cast, in accordance with BS 1400 Figure 2, from the same melt asthe casting it represents. It is advised that three tensile test specimens aremadeto enable retests in the event of failure of the initial test specimen.

7.3 Retests

a. Should the original test specimen fail tomeet acceptance standards, two furtherheat treated specimens from the same cast may be broken in accordance withBS EN 10002.

7.4 Non-Destructive Tests

a. Reference diagrams according to NES 863 are to be provided by the purchaserfor all Class I and Class II castings to show Critical Test Regions and TestRegions which are to be subjected to non-destructive testing (NDT).

7.5 Dimensional Check

a. All castings are to be fully dimensionally checked to ensure that they complywith NES 863.

7.6 Visual-Optical

a. All castings are to be 100% visually inspected, assisted where necessary, by theuse of ¢5 magnification optics. All imperfections are to be identified andrecorded.

7.7 Liquid-Penetrant

a. It is recommended that 100% liquid-penetrant examination, in accordance withNES 729 Part 4, is carried out on all Class I and Class II castings before anymachining operations are commenced to prevent nugatory work.

b. Where practicable, a 100% liquid penetrant inspection is to be undertaken onall surfaces of Class I and Class II castings with the surfaces examined in theirfinished condition.

7.8 Radiographic/Ultrasonic Examination

a. The manufacturer is to subject Critical Test Regions and Test Regions to either100% radiographic or 100% ultrasonic examination.

7.9 Radiography

a. Radiography is to be carried out in compliance with NES 729 Part 1. Allsub-surface imperfections are to be identified for subsequent assessment inaccordance with the acceptance standards.


7.2

7.10 Radiographic Examination of Non-Designated Regions on a Sample Basis

a. In certain circumstances examination by radiography on a sample basis may bespecified by contact or drawings to establish that a satisfactory general qualityof product is being supplied. Typical examples are:

(1) Lowly stressed Class II castings.

(2) Sample positions on large Class II or Class III castings.

(3) Batch supply of Class III castings.

7.11 Ultrasonic Examination

a. Ultrasonic examination is to be carried out in compliance with NES 729 Part 5.All sub-surface imperfections are to be identified for subsequent assessment inaccordance with the acceptance standards. Where ultrasonic examination isused the assessment of the casting is to be confirmed by radiography of selectedareas. A minimum of 10% of the total area examined by ultrasonics is to beradiographed.

NOTE: The grain structure of cast nickel aluminium bronze may precludeinspection by ultrasonics. The suitability for ultrasonic inspection is to beassessed in accordance with BS 6208 Clauses 9.2 and 9.3.

7.12 Pressure Tests

a. When stated in the contract the castings are to be subjected to the specifiedwater pressure test for a minimum period of 15 minutes. Certain castings mayrequire longer periods of pressure testing. When necessary this will be specifiedin the contract.

NES 747Part 2


8.1

8. ACCEPTANCE STANDARDS

8.1 Destructive Examination Standards

8.1.1 Analysis

a. Each chemical analysis is to conform to:

(1) TABLE 2.1, ingots.

(2) TABLE 2.2, castings.

8.2 Mechanical Tests

a. The tensile test result is to conform to TABLE 3.1 of this NES.

8.3 Retests

a. Both tensile test results are to conform to TABLE 3.1 of this NES.

8.4 Non-Destructive Examination Standards

8.4.1 Visual-Optical

a. On visual-optical inspection (Clause 7.6a.) the finished condition of all surfacesis to be clean and free from cracks or linear defects. Rounded forms of surfacedefects are unacceptable in Critical Test Regions and Test Regions but may beacceptable in Non-Designated Regions at the discretion of the AA.

NOTE: Defects are deemed to be rounded when aspect ratio of length towidth is 3:1 or less.

b. The surface finish is to meet the standard specified in the contract documentsand drawings.

8.4.2 Liquid-Penetrant

a. Indications of cracks, hot tears or chain-like porosity and surface oxideinclusions in linear formations are not acceptable.

b. Indications arising from porosity and surface oxide inclusions in non-linearformations are to be assessed as follows:

(1) Isolated pinpoint porosity is acceptable except in areas where sealing ofa housing against a running shaft is required, eg pump glands, propellershaft seals etc, and in flexible couplings.

(2) Clustered pinpoint porosity and other defects are acceptable providedthat:

(a) the maximum size of any indication is not to exceed 3mm diameterbleed out;

(b) the sum of the diameters of all indications for sections up to andincluding 50mm, in an area of 70 ¢ 70mm does not exceed 24mm;

OR

(c) the sum of the diameters of all indications for sections over 50mmin an area of 70 ¢ 70 does not exceed 36mm.


8.2

NOTE: The indications identified in Clause 8.4.2b.(1) and 8.4.2b.(2) areacceptable providing that the immediate area of the castings isacceptable when examined for sub-surface defects.

c. There may be instances where machined surfaces of castings manufactured tothis NES require more stringent acceptance standards than those inClause 8.4.2a. and 8.4.2b. eg in way of a wetted seal area. Where necessary thisrequirement is to be clearly stated in the contract documents and are to be thesubject of discussion between the purchaser and the contractor prior tomanufacture of the castings.

8.5 Radiography

a. Acceptance Standards are defined in NES 863.

8.6 Ultrasonics

a. Any defect that causes a signal greater than or equal to the signal produced bythe approved calibration standard is to be deemed unacceptable and the castingrepaired or rejected. Where the backwall echo is attenuated by 40% or greater,the examination by ultrasonics is unacceptable and radiography in accordancewith Clauses 7.8a. and 7.11a. are to be employed.

8.7 Pressure Tests

a. Each casting is to show no evidence of leakage.

NES 747Part 2


9.1

9. DEFECTS AND RECTIFICATION OF DEFECTS

9.1 Defects

a. Any casting may be rejected for defects discovered during subsequentmachining notwithstanding that the casting had been passed previously asconforming to this NES.

9.2 Rectification of Dimensional Defects by Weld Deposition

a. Correction of casting dimensions and machining errors may be made by welddeposition using an approved procedure for the material concerned and shall bewithin the following limits:

(1) Weld deposition thickness to be restricted to 20% of contract drawingsection thickness from 12mm to 50mm and to 10mm above 50mm sectionthickness.

(2) Area of weld deposition in Critical Test Regions and Test Regions to berestricted to 10% of the inner or outer surface area of the region, notincluding flange thicknesses and webs, subject to any limitations imposedby Clause 9.6a.

(3) Area of weld deposition in non-designated regions is to be restricted to20% of the inner or outer surface area of the region not including flangethickness and webs.

b. Weld build-up exceeding the tolerance on contract drawing section thickness isto be a reason for rejection.

9.3 Rectification of Surface Defects by Blending

a. Unacceptable surface defects may be blended out by an approved process,providing the resulting depression does not reduce the contract drawing sectionthickness bymore than 5mm for section thickness over 50mm, or 10% of sectionthicknesses up to and including 50mm. The depression sides and ends are to besmoothly blended out by a minimum radius of three times the maximum depthof blending and the edge formed with the surface is also to be faired smooth. Theremaining section thickness in way of the depression is to be free fromsub-surface defects as revealed by radiography or ultrasonics, in Critical TestRegions and Test Regions. The total area subjected to blending, including thearea affected by the fairing, is not to exceed 10% of any designated region or 20%of any non-designated region.

NOTE: Blending out of surface defects is preferable toweld repair wheneverpossible.

9.4 Rectification of Surface and Sub-Surface Defects by Welding

a. Unacceptable surface defects which cannot be blended out within thelimitations of Clause 9.3a. and unacceptable sub-surface defects may berepaired by welding using an approved procedure for the material concerned inaccordance with NES 771 and within the following limits:

(1) Area of excavation in Critical Test Regions and Test Regions is to berestricted to 10% of the surface area of the region, not including flangethicknesses and webs, subject to any limitations imposed by Clause 9.6a.

(2) Area of excavation in non-designated regions is to be restricted to 20% ofthe inner or outer surface area of the region, not including flangethicknesses and webs.


9.2

9.5 Limits on Individual Sub-Surface Repairs

a. Any individual repair in Critical Test Regions shall not exceed 5% of the testarea containing the defect. In Test Regions any individual repair shall notexceed 10% of test area containing the defect.

9.6 Limits on Combined Weld Repairs

a. The total combined area of weld repairs from all causes, eg dimensionalcorrection, surface and sub-surface defects is to be within the following limits:

(1) Total weld repair area of Class I and Class II castings is not to exceed 10%of the surface area of the casting, excluding flange thicknesses and webs.

(2) The total weld repair area of Class III castings is not to exceed 20% of thesurface area of the casting excluding flange thicknesses and webs.

9.7 Rectification of Defects

a. The rectification of surface and sub-surface defects by welding is to be inaccordance with NES 771.

b. Following heat treatment all weld repairs are to be examined in accordance withClauses 7.5a. to 7.12a. The weld repaired casting must satisfy the requirementsof Clause 7.12a.

9.8 Impregnation

a. Impregnation will not be accepted as a recovery procedure for Class I castings.Impregnation is a recognized recovery procedure for Class II and Class IIIcastings in accordance with Def Stan 03−1.

(1) Class II castings may be impregnated but only with the written approvalof the Acceptance Authority.

(2) Class III castingsmay be impregnated with the approval of theAcceptanceAuthority.

(3) The area of leakage necessitating remedial action does not exceed 10% of:

(a) The Test Region containing the defect in Class II castings.

(b) The total area pressure tested in non-designated regions in Class IIand Class III castings.

9.9 Special Repairs

a. Where the repairs necessary to meet the acceptance standards are moreextensive than are permitted by this specification and if it is considered thateffective economical repair is possible the contractor’s repair proposals, inaccordance with NES 771 may be submitted to the Acceptance Authority fordecision.

NES 747Part 2


10.1

10. IDENTIFICATION OF INGOTS AND CASTINGS

10.1 Ingots

a. Each ingot is to bemarked with the legend ‘NAB’ stamped or embossed in easilydiscernible letters. Each ingot is also to be marked with a unique cast numberwhich can be stamped or embossed in easily discernible letters, or an indeliblymarked self adhesive label is to be affixed. The unique cast number is topositively identify the ingot to its quality assurance documentation.

10.2 Castings

a. Each casting is to be clearly identifiable during manufacture and bepermanently marked for identification during service life with the followingdetails:

(1) Pattern or Ship’s Identity Number plus NES 747 Part 2.

(2) Class of casting, ie CI, CII, CIII.

(3) The legend ‘NAB’.

(4) The unique cast number which can be related to the quality controldocumentation.

NOTE: Castings subject to validation in accordance with DPT 1311Specification are to be marked in accordance with that specificationin addition to the requirements of Clause 10.2a.(1)−10.2a.(4).

b. The markings detailed in Clause 10.2a. are to be stamped, engraved orvibro-etched in the position indicated on the drawing. Markings are to be asconspicuous as the nature of the casting allows and provision is to be made fortransferring identification markings during manufacture so that traceability ismaintained throughout the service life of a casting. The markings are not to bemade on the highly stressed region, eg Critical Test Regions of the casting.

c. Where difficulty is being experienced in satisfactorily applying identificationsymbols, this is to be resolved by consulting the Acceptance Authority.


10.2

NES 747Part 2


11.1

11. PACKAGING

a. Except where otherwise stated in the contract, packaging is to be in accordancewith the contractor’s normal practice subject to the affixing of a trade warninglabel and the addition of the following identification details on each package orcase:

(1) Description of castings.

(2) Quantity.

(3) Contract Number.


11.2

NES 747Part 2


A.1 ANNEX A.

ANNEX A.

RELATED DOCUMENTS

A.1 The following documents and publications are referred to in this NES:

See Clause

BS 375 Specification for refined nickel 2.a.

BS 1400 Specification for copper alloy ingots andcopper alloy and high conductivity coppercastings

7.2a.

BS 6017 Specification for copper refinery shapes 2.a.

BS 6208 Method for ultrasonic testing of ferritic steelcastings including quality levels

7.11a.

BS EN 10002 Tensile testing of metallic materials B.1, 7.2a.,7.3a.

DEF STAN 03−1 Impregnation of porous castings 9.8a.

NES 729 Requirements for Non-DestructiveExamination Methods:Part 1: Radiographic 7.9a.

Part 4: Liquid Penetrant B.1, 7.7a.

Part 5: Ultrasonic 7.11a.

NES 746 Approval and Control of Heat TreatmentFurnaces

4.c.

NES 771 Requirements Procedure and Inspection forWeld Repair of Copper Alloy and Nickel AlloyCastings

9.4a., 9.7a.,9.9a.

NES 863 Requirements for the Classification,Dimensions, Tolerances and GeneralStandards of Acceptance for Copper andNickel Alloy Castings

1.a., 5.a.,7.4a., 7.5a.,8.5a.

DPT 1311 Validation Procedure for Existing FinishedMachined Castings

10.2a.


A.2ANNEX A.

NES 747Part 2


B.1 ANNEX B.

ANNEX B.

DEFINITIONS AND ABBREVIATIONS

B.1 For the purpose of this NES the following definitions apply:

Acceptance Authority (AA) The Acceptance Authority is asspecified in the contract. Where this isnot known by the Contractor, enquiriesare to be forwarded to DNA,Section NA 115, Foxhill, Bath.

Approved Scrap Scrap that is derived from nickelaluminium bronze, the composition ofwhich has been established with regardto the complete range of both thealloying elements and impurityelements and is segregated andidentifiable to the satisfaction of theMOD(PE)/AA.

Cast A cast is:

the product of one furnace melt

or

the product of one crucible melt

or

the product of a number offurnace or crucible melts wheresuch are aggregated and mixedprior to sampling.

Contractor The Firm, Company, Organization, orEstablishment working within thescope of this NES.

Ingots A mass of metal of proportions to suitthe Founder’s requirements.

Large/Complex castings Castings which the Design Authorityconsiders are liable to require weldrepair on the wetted surfaces duringmanufacture.

Pinpoint Porosity Any circular bled out of less than0.5mm diameter revealed during liquidpenetrant examination in accordancewith NES 729 Part 4.

S The cross-section area of the gauge in atensile piece, before testing as detailedin BS EN 10002.

Wetted Surface A surface that will come into contactwith sea water.


B.2ANNEX B.

NES 747Part 2


C.1 ANNEX C.

ANNEX C.

PROCUREMENT CHECK LIST

Notes:1. This Check List is to ensure that certain aspects of this Naval Engineering

Standard are consulted when preparing a Statement of TechnicalRequirements for a particular application.

2. Clauses where a preference for an option is to be used or where specific data isto be added are included in the Check Listto be added are included in the Check List.

3. Each item is to be marked either

! = included

NA = not applicable

CHECKNo CHECK CLAUSE No ! or NA

1 Radiographic Examination of Non-DesignatedRegions on a Sample Basis

7.10a.

2 Pressure Tests 7.12a.

3 Acceptance Standards for Machined Surfaces 8.4.2c.

4 Packaging 11.a.


C.2ANNEX C.

Inside Rear Cover

© Crown Copyright 2000

Copying Only as Agreed with DStan

Defence Standards are Published by and Obtainable from:

Defence Procurement AgencyAn Executive Agency of The Ministry of Defence

Directorate of StandardizationKentigern House65 Brown Street

GLASGOW G2 8EX

DStan Helpdesk

Tel 0141 224 2531/2 Fax 0141 224 2503

Internet e-mail [email protected]

File Reference

The DStan file reference relating to work on this standard is D/DStan/69/02/747.

Contract Requirements

When Defence Standards are incorporated into contracts users are responsible for their correctapplication and for complying with contractual and statutory requirements. Compliance witha Defence Standard does not in itself confer immunity from legal obligations.

Revision of Defence Standards

Defence Standards are revised as necessary by up issue or amendment. It is important thatusers of Defence Standards should ascertain that they are in possession of the latest issue oramendment. Information on all Defence Standards is contained in Def Stan 00-00 Standardsfor Defence Part 3 , Index of Standards for Defence Procurement Section 4 ‘Index of DefenceStandards and Defence Specifications’ published annually and supplemented regularly byStandards in Defence News (SID News). Any person who, when making use of a DefenceStandard encounters an inaccuracy or ambiguity is requested to notify the Directorate ofStandardization (DStan) without delay in order that the matter may be investigated andappropriate action taken.

moduk def stan 02-747 part 2

Documents

castings onlypart

thewetted surfacethe

daterevision notethis

historical recordthis

sand castingswith welding

wetted surfacepart

wetted surfacedstandstan

publication date