NES 849 Steel Castings for Structural Engineering and Pressure Purposes Category 2

Ministry of Defence Defence Standard 02-849 (NES 849)

Issue 1 Publication Date 01 April 2000

Incorporating NES 849 Category 2

Issue 1 Publication Date May 1989

Steel Castings For Structural,Engineering And Pressure Purposes

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) 849 Issue 1 dated May 1989.

Ministry of Defence

Naval Engineering Standard

NES 849 Issue 1 (Reformatted) May 1989

STEEL CASTINGS FOR STRUCTURALENGINEERING AND PRESSURE PURPOSES

This NES Supersedes

DG SHIPS 6080DG SHIPS 6081DG SHIPS 8081

Record of Amendments

AMDT INSERTED BY DATE

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i

NAVAL ENGINEERING STANDARD 849

ISSUE 1 (REFORMATTED)

STEEL CASTINGS FOR STRUCTURAL

ENGINEERING AND PRESSURE PURPOSES

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

ii

NES 849Issue 1 (Reformatted)

iii

SCOPE

1. This NES gives the requirements for the manufacture, inspection and testing of steel castingsfor structural and engineering purposes for HM Ships and general engineering purposes forSubmarines.

2. Seven types of steel castings for different combinations of service conditions are detailedherein under the following designations:

Type A Carbon steel

Type B Carbon steel

Type C Carbon steel

Type D Carbon molybdenum steel

Type E Carbon molybdenum steel

Type F Carbon molybdenum steel

Type G 2.25% chromium—1% molybdenum steel


iv


v

FOREWORD

Sponsorship

1. ThisNaval Engineering Standard (NES) is sponsored by theProcurement Executive, Ministryof Defence, Chief Naval Architect (CNA), Section NA 132.

2. It is to be applied as required to any Ministry of Defence contract for the purchase of steelcastings for general engineering purposes and is applicable to Surface Ships and Submarines.

3. If it is found to be technically unsuitable for any particular requirement the Sponsor is to beinformed in writing of the circumstances with a copy to CNA, Section NA 145.

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

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

b. directly applicable to a particular contract are to be dealt with using existing proceduresor as specified in the contract.

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

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

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.

Conditions of Release

General

8. 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.

9. 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.

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

MOD Tender or Contract Process

11. 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.

12. 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,


vi

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.

13. 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

14. 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.

15. 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.

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

Health and Safety

Warning

17. 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.


vii

CONTENTSPage No

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

SCOPE iii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

General v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MOD Tender or Contract Process v. . . . . . . . . . . . . . . . . . . . . . . . . .

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

Warning vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTENTS vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 1. DESIGNATIONS 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .TABLE 1.1 MATERIAL DESIGNATIONS 1.1. . . . . .

1.1 Elevated Temperature 1.1. . . . . . . . . . . . . . . . . . . . . . . .1.2 Low Temperature 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 2. CHEMICAL ANALYSIS 2.1. . . . . . . . . . . . . . . . . . . . . .TABLE 2.1 COMPOSITION 2.1. . . . . . . . . . . . . . . . . .

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

SECTION 4. MANUFACTURE 4.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .4.1 Heat Treatment 4.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 5. CLASSIFICATIONS 5.1. . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 6. DELINEATION OF AREAS FORNON-DESTRUCTIVE TESTING 6.1. . . . . . . . . . . . . . .

6.1 Critical Test Region 6.1. . . . . . . . . . . . . . . . . . . . . . . . . .6.2 Test Region 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.3 Unclassified Region 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 7. DIMENSIONS AND TOLERANCES 7.1. . . . . . . . . . .7.1 Schedule of Inspection 7.1. . . . . . . . . . . . . . . . . . . . . . . .7.2 Tolerances 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 8. QUALITY ASSURANCE DOCUMENTATION 8.1. . .

SECTION 9. TEST METHODS 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1 Destructive Tests 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1.1 Analysis 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1.2 Mechanical Tests 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.1.3 Test Pieces 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.2 Retests 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


viii

9.3 Non-destructive Tests 9.1. . . . . . . . . . . . . . . . . . . . . . . . .9.3.1 Dimensional 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.3.2 Visual 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.3.3 Magnetic Particle and Liquid Penetrant 9.1. . . . . . . . .9.3.4 Radiography 9.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.3.5 Ultrasonics 9.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.3.6 Pressure Tests 9.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 10. ACCEPTANCE STANDARDS 10.1. . . . . . . . . . . . . . . . .10.1 Destructive Examination Standards 10.1. . . . . . . . . . . . .10.1.1 Analysis 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.1.2 Tensile Tests 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.1.3 Charpy V-notch 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.1.4 Retests 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.2 Non-Destructive Examination Standards 10.1. . . . . . . .10.2.1 Dimensional 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.2.2 Visual 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.2.3 Magnetic Particle and Liquid Penetrant 10.1. . . . . . . . .10.2.4 Radiography 10.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.2.5 Ultrasonics 10.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10.2.6 Pressure Tests 10.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 11. DEFECTS AND RECTIFICATION OF DEFECTS 11.111.1 Defects 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11.2 Limits on Repair 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .11.3 Pre-welding Requirements 11.1. . . . . . . . . . . . . . . . . . . . .11.4 Heat Treatment 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11.5 Impregnation 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 12. IDENTIFICATION OF CASTING 12.1. . . . . . . . . . . . . .

SECTION 13. PACKAGING 13.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

ANNEX C. ULTRASONIC REFERENCE STANDARD C.1. . . . . .FIGURE C.1 C.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ANNEX D. PROCUREMENT CHECK LIST D.1. . . . . . . . . . . . . . .

ALPHABETICAL INDEX


1.1

1. DESIGNATIONS

a. Casting material is to be selected from TABLE 1.1 to meet the specific serviceenvironment for which it is intended.

Environment Material Type UTSN/mm2 Reference

Room Temperature CC Mo.

430460

AD

Room and ElevatedTemperature

CC Mo.

2¼ Cr. 1 Mo.

430460540

BEG

Room and Sub-ZeroedTemperature

CC. Mo.

430460

CF

TABLE 1.1 MATERIAL DESIGNATIONS

1.1 Elevated Temperature

a. Type E would be selected for engine or machinery castings which require goodimpact, shock resistance and elevated temperature properties. Where superiorcreep properties are required Type G is to be selected.

1.2 Low Temperature

a. For Type C and Type F the designations LT40 and LT50 indicate the minustemperature at which impact properties are tested.


1.2


2.1

2. CHEMICAL ANALYSIS

a. The castings supplied to this NES are to conform to the chemical compositionrequired by TABLE 2.1.

Casting Material to Conform to

Type A BS 1504—161 Grade 430 A

Type B BS 1504—161 Grade 430 E

Type C BS 1504—161 Grade 430 LT40

Type D BS 1504—245 A

Type E BS 1504—145 E

Type F BS 1504—245 LT50

Type G BS 1504—622E

TABLE 2.1 COMPOSITION


2.2


3.1

3. MECHANICAL PROPERTIES

a. TABLE 3.1 details the minimum mechanical properties and test temperaturesfor Types A to G steel castings.

TensileStrengthUTSN/mm2

Proof Stress 0.2%

N/mm2

Elong5.65

%

SOAverage Charpy

V-Notch

J

TestTemp Room Room 300°C 500° C Room Room −40° C −50° C

Type A 430 230 − − 20 25 − −

Type B 430 230 148 − 20 25 − −

Type C 430 230 − − 20 − 20 −

Type D 460 260 − − 18 20 − −

Type E 460 260 − 151 18 20 − −

Type F 460 260 − − 18 − − 20

Type G 540 325 − 240 17 25 − −

TABLE 3.1 MECHANICAL PROPERTIES


3.2


4.1

4. MANUFACTURE

a. The castings are to be manufactured using the latest techniques and are to beof such a quality and purity that on completion they have the requiredcomposition and properties when tested in accordance with this standard.

b. To obtain test results which are representative of the actual casting or batch ofcastings all test bars are to be cast attached to the casting to which they referand are to remain attached until the completion of the heat treatment cycles.

c. The test bars are to be representative of the thickest and thinnest sectionswithin the casting or batch.

d. Material for retests is not to be machined to the finished test bar size prior toany further heat treatments.

e. The location of the test bars is to be agreed between the purchaser and themanufacturers since their position could adversely affect the casting quality.

f. Should the design of the castingmake it undesirable to provide cast-on test barsthe manufacturer is to consult the QAR to allow in extreme cases the provisionof separately cast keel bars.

4.1 Heat Treatment

a. Each casting is to be supplied in the heat treated condition the details of whichare quoted in BS 1504 under the relevant material specification.

b. The heat treatment furnaces used are to be fitted with automatic temperaturecontrols and with graphical temperature recorders.

c. Themanufacturer is required to demonstrate to theQAR that the furnaces usedare capable of providing an even distribution of heat at the correct temperature.


4.2


5.1

5. CLASSIFICATIONS

a. The classification of castings in accordance with NES 745 is as follows:

Class 1 a casting whose failure would lead to uncontrollable flooding, the totalimmobilization of the vessel, or a serious hazard to personnel.

Class 2 a casting whose failure would lead to severe but controllable flooding, theserious disruption of the weapon systems, main propulsion machinery, orits attendant auxiliaries including generators.

Class 3 all other castings where their failure would not constitute an immediatesignificant hazard.

Note: It is incumbent upon designers to avoid over-classifying castings on thegrounds that doing so adds additional costs to components.


5.2


6.1

6. DELINEATION OF AREAS FOR NON-DESTRUCTIVE TESTING

a. Each casting is to be divided into regions of criticality, ie critical, test, andunclassified. These designations will determine the degree of inspection to becarried out and the standard of acceptance.

6.1 Critical Test Region

a. This will apply to certain areas of a Class 1 casting. The remainder of a Class1 casting is to be designated as a Test Region.

6.2 Test Region

a. This will also apply to certain areas of a Class 2 casting. The remainder of aClass 2 casting is to be unclassified.

6.3 Unclassified Region

a. This will also apply to the whole of a Class 3 casting.

b. Critical Test regions and Test regions are to be marked on reference drawingsas follows:

(1) critical test regions are to be indicated by cross hatching in full lines at 45°from upper left to lower right;

(2) test regions are to be indicated by cross hatching in short chain dottedlines at 45° from upper right to lower left.


6.2


7.1

7. DIMENSIONS AND TOLERANCES

a. Before finalizing a design, the designer is to consult a foundry methods engineerto allow incorporation of any modifications or change in design which mightassist in the production of sound castings.

7.1 Schedule of Inspection

a. Following agreement of the design features and the issue of casting drawings,the purchaser is to provide a complete Schedule of Inspection prepared by thedesigner and agreed by the founder which will include a marked up drawingindicating the extent of Critical Test Regions and Test Regions, whereapplicable, in accordance with Section 6.

b. The Schedule of Inspection is to define:

(1) surface finish;

(2) classification;

(3) any restriction on the repair of the castings;

(4) non-destructive testing and pressure test requirements.

c. The designer is to make allowances in the factors of safety of the component totake account of the reduced strength which occurs within the acceptance levelsdetailed in Section 10.

7.2 Tolerances

a. The casting tolerances are to be agreed between the purchaser and themanufacturer and the minimum wall thickness after final machining is to bestated on the drawing. The casting is to be capable of beingmachined to finisheddimensions within leaving evidence of the cast surface and accepted inaccordance with Section 10.


7.2


8.1

8. QUALITY ASSURANCE DOCUMENTATION

a. It is a requirement for Class 1 and Class 2 castings that each consignment ofcastings is to be accompanied by Quality Assurance Documentation. This is toinclude the actual results of the tests required by Section 9. together withCertificates of Conformity with the relevant acceptance standards detailed inSection 10. and a copy of the print out from the heat treatment furnacetemperature recorder.

b. Class 3 castings are to be accompanied by a Statement of Compliance only,unless further Quality Assurance Documentation is specified in the ContractDocuments.


8.2


9.1

9. TEST METHODS

9.1 Destructive Tests

9.1.1 Analysis

a. A full chemical analysis is to be made from each cast.

9.1.2 Mechanical Tests

a. One set of tests is required from each cast and it is advised that extra materialbe available to enable retests in the event of failure of the initial test.

b. Tensile tests at room temperature are to be carried out inaccordance withBS 18and are to include the determination of the proof stress.

c. Tensile tests at elevated temperatures are to be carried out in accordance withBS 3688 Part 1 for the determination of the proof stress.

d. Charpy V-notch impact tests are to be carried out in accordance with BS 131Part 2 at the temperature quoted in TABLE 2.1. A minimum of three impacttests are to be made for each test.

9.1.3 Test Pieces

a. All test pieces are to be permanently marked with the cast and batch numbersor a number which will ensure unique traceability of the material.

b. To ensure representative results all machined test pieces require a surfacefinish of 0.8μm Ra or better.

c. Unless authorized by the QAR all test pieces are to be retained for a period oftwo months after completion of the contract or delivery of the material.

9.2 Retests

a. Should any of the original mechanical test pieces fail to satisfy the requirementsof TABLE 2.1 the manufacturer is to take one of the following actions:

(1) carry out two additional tensiles, if the original failed or an additional setof charpy V-notch tests if they originally failed, or

(2) reheat-treat the casting with suitable test material securely attached andthen carry out new mechanical tests.

9.3 Non-destructive Tests

9.3.1 Dimensional

a. Checks are to be carried out on each casting to ensure that the design drawingrequirements can be met (see Section 7.).

9.3.2 Visual

a. All castings are to be subjected to 100% visual examination assisted whennecessary by the use of ¢5 magnification optics. All imperfections are to beidentified and recorded on the Quality Assurance Documentation.

9.3.3 Magnetic Particle and Liquid Penetrant

a. All Class I and Class 2 castings are to be subjected to 100% of either magneticparticle or liquid penetrant examination in accordance with NES 729 Part 2 orPart 4 before any machining operations are commenced. All casting surfaceswhich are subsequently machined are to be subjected to a further examinationon completion.


9.2

9.3.4 Radiography

a. The manufacturer can opt to subject designated Critical Test and Test Regionsto either 100% radiography or 100% ultrasonic examination. Radiography is tobe carried out in accordance with NES 729 Part 1, all subsurface imperfectionsfound by this examination are to be identified for subsequent assessment inaccordance with the acceptance standards in Section 10.

9.3.5 Ultrasonics

a. When it is proposed to use ultrasonic examination the manufacturer is toforward the inspection technique and procedure to the QAR for approval withNES 729 Part 5. To confirm the findings of the ultrasonic examination aminimum of 10% of the area of the casting examined is to be radiographed.

9.3.6 Pressure Tests

a. When required by the Contract Documents the castings are to be subjected toa pressure test for the minimum duration of 15 minutes. Certain castings mayrequire longer periods of test and these together with test pressures will bespecified in the Contract Documents.


10.1

10. ACCEPTANCE STANDARDS

10.1 Destructive Examination Standards

10.1.1 Analysis

a. The chemical analysis is to conform to the relevant material specificationquoted in BS 1504.

10.1.2 Tensile Tests

a. Each tensile test result is to meet the requirements laid down in TABLE 2.1 forthe appropriate material and test temperature.

10.1.3 Charpy V-notch

a. The average of three impact tests made is to be no less than the value quotedin TABLE 3.1. No single value is to be lower than 70% of the value quoted inTABLE 3.1.

10.1.4 Retests

a. The two tensile retest specimen results are to conform to the requirements inTABLE 3.1. The additional set of charpy V-notch impact tests together with theresults of the original tests are to satisfy the following:

(1) the average of the six is to be not less than the specified value inTABLE 3.1;

(2) no more than two of the individual values is to be less than that specifiedin TABLE 3.1;

(3) no more than one is to be less than 70% of the value specified inTABLE 3.1.

b. Where test pieces are found, on testing, to have visually obvious casting defects,the results are to be ignored and a new test piece prepared.

10.2 Non-Destructive Examination Standards

10.2.1 Dimensional

a. The castings are to be dimensionally within the tolerances stated on thecontract drawings and when no tolerances are given, subject to agreementbetween the purchaser and manufacturer, a tolerance of ±10% or 6mm—whichever is the less—on the designed wall thickness will be permitted on allcasting dimensions. The reduced wall thickness is to be free from sub-surfacedefects in both Critical Test and Test Regions. The total area of reducedthickness is not to exceed 10% of each individually designated test region.

10.2.2 Visual

a. The finished surface of the casting is to be free from cracks, hot tears, cold shutsor linear defects. The surface finish is to meet the standard specified in theContract Documents and drawings.

10.2.3 Magnetic Particle and Liquid Penetrant

a. All surfaces are to be free from cracks, hot tears or chain like porosity. Isolatedpin-point porosity is acceptable. Where porosity is present, indications whichare larger than pin-point are limited as follows:


10.2

(1) the maximum number of indications is not to exceed 8 of 8mm diameterin any 5000mm2;

(2) the sum of the diameter of indications in an area of 5000mm2 must notexceed 24mm.

10.2.4 Radiography

a. Cracks, hot tears and cold shuts in any area of the casting and lack of fusion inweld repair areas are not acceptable. Internal porosity and shrinkage areacceptable when:

(1) in Critical Test Regions the local reduction in wall thickness does notexceed 5% of the designed wall thickness and the total defective area doesnot exceed 500mm2 or 10% whichever is the smaller and,

(2) in Test regions the local reduction in wall thickness does not exceed 10%of the designated wall thickness and the total defective area does notexceed 1000mm2 or 20% whichever is the smaller.

10.2.5 Ultrasonics

a. Any defect which causes a signal greater than or equal to the signal producedby the approved reference standard shown in Annex C. is to be deemedunacceptable and the casting rejected. Where the backwall echo is attenuatedby 40% or greater, the examination by ultrasonics is unacceptable andradiography in accordance with Clause 9.3.4a. is to be employed.

10.2.6 Pressure Tests

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


11.1

11. DEFECTS AND RECTIFICATION OF DEFECTS

11.1 Defects

a. In the event of subsequent manufacturing operations revealing unacceptabledefects capable of detection by the inspection techniques prior to delivery thecasting can be rejected.

11.2 Limits on Repair

a. The limits on the extent of repairs for dimensional, surface and subsurface areto be in accordance with NES 745.

b. All welding is to be in accordance with NES 706with regard to welding process,weld procedure, weld preparation and consumable selection.

11.3 Pre-welding Requirements

a. After excavation the weld area is to be examined to ensure the defect has beenremoved. Welding is only to be carried out on sound material.

11.4 Heat Treatment

a. Welding is only to be carried out on castings which have been fully heat treatedand after acceptance mechanical testing has been completed. The casting is tobe subjected to a post weld stress relief and the temperature is to be as quotedfor the relevant material specification in BS 1504.

11.5 Impregnation

a. Impregnation is not to be used as a recovery procedure for Class1 castings. Class2 and 3 castings can be recovered using impregnation in accordance withDEF STAN 03−1 when approved by the Design Authority.


11.2


12.1

12. IDENTIFICATION OF CASTING

a. For identification purposes, all castings are to be legibly marked by themanufacturer with the following particulars:

(1) The material designation and NES 849 Type X.

(2) Class of casting, ie C1, C2 or C3.

(3) Unique cast number which can be related to the Quality ControlDocumentation.

b. The markings detailed in Clause 12.a. are to be cast-on, stamped, using lowstress stamps in a non-critical area, engraved or vibro-etched in the positionindicated on the drawings. Markings are to be as conspicuous as the nature ofthe casting allows and provision is to be made for transferring identificationmarkings during manufacture such that traceability is maintained throughoutthe service life of the casting. The markings are not to be made on the highlystressed regions, eg Critical Test Region of the casting.

c. Where difficulty is being experienced in satisfactorily applying identificationsymbols it is to be resolved by consulting the QAR.


12.2


13.1

13. PACKAGING

a. Except where otherwise stated in the Contract Documents packaging is to bein accordance with the contractor’s normal trade practice which is to ensurethat no damage occurs during transit.

b. Each package is to carry a label marked with the following additionalidentification details:

(1) NATO stock number when applicable.

(2) Description of castings.

(3) Quantity.

(4) Contract number.


13.2


A.1 ANNEX A.

ANNEX A.

RELATED DOCUMENTS

A.1 Reference is made to:

Referred to inClause

BS 18 Methods for tensile testing of metals 9.1.2b.

BS 131 Part 2 The Izod impact test on metalsPt 2 The Charpy V-Notch impact test onmetals

9.1.2d.

BS 1504 Steel castings for pressure purposes 2.a., 4.1a.,10.1.1a., 11.4a.

BS 3688 Part 1 Methods for mechanical testing of metalsat elevated temperaturesPt 1 Tensile testing

9.1.2c.

DEF STAN 03−1 Impregnation of porous castings 11.5a.

NES 706 Welding and fabrication of ship structure 11.2b.

NES 729 Requirements for Non-DestructiveExamination MethodsPart 1 Radiographic 9.3.4a.

Part 2 Magnetic Particle 9.3.3a.

Part 4 Liquid Penetrant Annex B., 9.3.3a.

Part 5 Ultrasonic 9.3.5a.

*NES 745(DG Ships/PS/9010)

Classification, Inspection Requirementsand Acceptance Standards of Steel andCopper-base Alloy Castings

5.a., 11.2a.

Note: *In course of preparation. When published will supersede stateddocument.


A.2ANNEX A.


B.1 ANNEX B.

ANNEX B.

DEFINITIONS AND ABBREVIATIONS

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

Acceptance Authority the Design Authority for the systems orequipments concerned.

Cast a cast is:

a. the product of one furnace melt, or

b. the product of one crucible melt, or

c. the product of a number of furnace or cruciblemelts where such are aggregated prior to sampling.

Certificate of Conformity this is supplied with material of which traceabilityduring manufacturing is required and is issued onthe basis of the required tests having been carriedout on the casts from which the material suppliedhas been taken.

Contractor the firm, Company Organization or Establishmentworking within the scope of this NES.

Design Authority the relevant Section of Sea Systems Controllerate,Foxhill, Bath, responsible for the systemconcerned. Where this is not known by theContractor, enquiries are to be forwarded to DCW,Section NA 132, Foxhill, Bath.

Pinpoint Porosity any circular bleed out of less than 0.5mm diameterrevealed during liquid dye penetrant examinationin accordance with NES 729, Part 4.

Quality AssuranceAuthority (QAA)

the authority designated in a contract asresponsible for quality assurance matters relatingto that contract.

Quality AssuranceRepresentative (QAR)

any officer duly authorized to act on behalf of theQAA and the Project Manager.

Statement of Compliance this is supplied with material of which traceabilityduring manufacture is not required. It ensuresthat the material complies with the conditions ofthis NES in accordance with the manufacturersquality control procedures.


B.2ANNEX B.


C.1 ANNEX C.

ANNEX C.

ULTRASONIC REFERENCE STANDARD

FIGURE C.1

T = Thickness to be tested ±10%

{ = the block may be cut to this line to facilitate drilling where a single blockis required for use. Alternatively a number of separate reference blocksmay be employed.

Thickness to be examined (mm) Dia of FBH (mm)

Up to and incl 50 1.5

Over 50 to 75 (incl) 2.5

Over 75 to 100 incl 3.0

Over 100 4.0

NOTES:

1. The flat bottom of the holes (FBH) is to be parallel to the entrant surface.

2. The reference standard is to bewide enough to permit sound transmissionto the flat bottom holes without side effects.

3. The reference standard material is to be ultrasonically free from obviousdefects and similar to the material being tested. The surface finish is tobe comparable to the test surface and of similar contour.

4. The test frequency is to be the same as the calibration frequency.

5. The equipment is to be set to show a minimum echo of 20% full screendeflection from each hole within the thickness to be inspected.


C.2ANNEX C.


D.1 ANNEX D.

ANNEX D.

PROCUREMENT CHECK LIST

TITLE ......................................................

REFERENCE ......................................................

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

Engineering Standard are consulted when preparing a Statement ofTechnical Requirements for a particular application.

2. Clauses where a preference for an option is to be used or where specificdata is to be added are included in the Check Listdata is to 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 Steel Designation 1.1a., 1.2a.

2 Elevated Temp, Properties 3.a.

3 Low Temp, Properties 3.a.

4 Classification of Casting 5.a.

5 Delineation of Test Area 6.a., 6.1a.,6.2a., 6.3a.

6 Quality Assurance Documentation 8.a., 8.b.

7 Pressure Test 9.3.6a.

8 Packaging 13.a.


D.2ANNEX D.


INDEXINDEX.1

ALPHABETICAL INDEX

AAnalysis, 9.1, 10.1

CCertificate of compliance, 8.1

Charpy V-notch, 10.1

Chemical composition, 2.1

Controls on thermal treatment, 4.1

Critical test Region, 6.1

DDefect rectification, 11.1

Defects, 11.1

Destructive tests, 9.1

Dimensional, 9.1

Dimensions, 7.1

EElevated temperature, 1.1

HHeat treatment, 4.1, 11.1

IIdentification, 2.1

Impregnation, 11.1

LLabels, 13.1

Limits on repair, 11.1

Liquid penetrant, 9.1, 10.1

Low temperature, 1.1


INDEX INDEX.2

MMagnetic particle, 9.1, 10.1

Manufacture, 4.1

Marking, 12.1

Mechanical tests, 9.1

NNon-destructive examination standards, 10.1

Non-destructive tests, 9.1

PPackaging, 13.1

Pre-welding requirements, 11.1

Pressure tests, 9.2, 10.2

QQuality assurance, 8.1

RRadiography, 9.2, 10.2

Retests, 9.1, 10.1

SSchedule of inspection, 8.1

Statement of compliance, 8.1

TTemperature, 1.1

Tensile tests, 10.1

Test pieces, 4.1, 9.1

Test region, 6.1

Tests, destructive, 9.1

Tests, non-destructive, 9.1

Thermal treatment, 4.1

Tolerances, 7.1


INDEXINDEX.3

UUltrasonics, 9.2, 10.2

Ultrasonics reference standard, C.1

Unclassified test region, 6.1

VVisual, 9.1, 10.1

WWelding, 11.1


INDEX INDEX.4

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