NES 825 Requirements for Welding Copper Nickel Chromium Sand Castings (Including Welding Wire) Category 2

Ministry of Defence Defence Standard 02-825 (NES 825) Issue 1 Publication Date 01 April 2000

Requirements For Welding Copper Nickel Chromium Sand Castings (Including Welding Wire)

Incorporating NES 825 Category 2 Issue 2 Publication Date June 1989

AMENDMENT RECORD Amd No

D at e

Text Affected

REVISION NOTE

This standard is raised to Issue 1 to update its content. HISTORICAL RECORD This standard supersedes the following:

 Naval Engineeri E ngineering ng Standard Standar d (NES) 825 8 25 Issue 2 dated June 1989.

S i g n at u r e a n d D at e

AMENDMENT RECORD Amd No

D at e

Text Affected

REVISION NOTE

This standard is raised to Issue 1 to update its content. HISTORICAL RECORD This standard supersedes the following:

 Naval Engineeri E ngineering ng Standard Standar d (NES) 825 8 25 Issue 2 dated June 1989.

S i g n at u r e a n d D at e

Ministry of Defence

Naval Engineering Standard

NES 825

Issue 2 (Reformatted)

June 1989

REQUIREMENTS FOR WELDING COPPER NICKEL CHROMIUM SAND CASTINGS (INCLUDING WELDING WIRE)

This NES Supersedes Supersedes NES 825 ISSUE 1

Record of Amendments AMDT 1 2 3 4 5 6 7 8 9 10

INSERTED BY  

INCORPORATED

DATE

NAVAL ENGINEERING STANDARD 825 ISSUE 2 (REFORMATTED) (REFORMATTED) REQUIREMENTS FOR WELDING COPPER NICKEL CHROMIUM SAND CASTINGS (INCLUDING WELDING  WIRE)

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 Architecture Procurement Executive, Ministry of Defence Sea Systems, Foxhill, Bath BA1 5AB i

ii

NES 825 Issue 2 (Reformatted)

SCOPE 1.

This NES specifies the minimum requirements, procedure and inspection standards for the welding repair of Copper Nickel Chromium Sand Castings supplied in accordance with NES 824 Part 1 and also the procurement specification for welding wire.

iii

NES 825 Issue 2 (Reformatted)

iv

NES 825 Issue 2 (Reformatted)

FOREWORD Sponsorship 1.

This Naval Engineering Standard (NES) is sponsored by the Procurement Executive, Ministry of Defence, Chief Naval Architect (CNA), Section NA 133.

2.

It is to be applied as required by any Ministry of Defence contract for welding Copper Nickel Chromium Sand Castings and for the procurement of welding wire 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 be informed 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 amendment to 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 procedures or 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 similar terms means by the Ministry of Defence.

7.

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

8.

This NES has been reissued due to substantial amendments including changes in paragraph numbering.

Conditions of Release

General 9.

This Naval Engineering Standard (NES) has been prepared for the use of the Crown and of  its contractors in the execution of contracts for the Crown. The Crown hereby excludes all liability (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 or third party rights. It is not to be released, reproduced or published without written permission of the MOD.

11.

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

v

NES 825 Issue 2 (Reformatted)

MOD Tender or Contract Process 12.

This NES is the property of the Crown and unless otherwise authorized in writing by the MOD must be returned on completion of the contract, or submission of the tender, in connection with which it is issued.

13.

When this NES is used in connection with a MOD tender or contract, the user is to ensure that he 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 of  the local MOD(PE) Quality Assurance Representative or the Authority named in the tender or contract.

14.

When NES are incorporated into MOD contracts, users are responsible for their correct application 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 and  Annex 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 relevant MOD Invitation to Tender or Contract Number and date, together with the sponsoring  Directorate and the Tender or Contract Sponsor.

17.

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

Health and Safety

Warning 18.

This NES may call for the use of processes, substances and/or procedures that may be injurious to health if adequate precautions are not taken. It refers only to technical suitability and in no way absolves either the supplier or the user from statutory obligations relating to health and safety at any stage of manufacture or use. Where attention is drawn to hazards, those quoted may not necessarily be exhaustive.

vi

NES 825 Issue 2 (Reformatted)

CONTENTS Page No

TITLE PAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

i

SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

iii

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sponsorship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conditions of Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MOD Tender or Contract Process . . . . . . . . . . . . . . . . . . . . . . . . . . Related Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Health and Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

v v v v vi vi vi vi

CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii

SECTION

QUALIFICATION REQUIREMENTS . . . . . . . . . . Weld Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Repair by Surface Build-Up . . . . . . . . . . . . . . . . . . . Repair of Sub-Surface Defects . . . . . . . . . . . . . . . . . Repair Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . FIGURE 1.1 SURFACE BUILD-UP WELDER AND PROCEDURE QUALIFICATION TEST PIECE . . . . . . . . . . . . . . . FIGURE 1.2 SUB-SURFACE REPAIR WELDER AND PROCEDURE QUALIFICATION POSITION OF TEST SPECIMENS . . . . . . . . . . . . . . . . . . . . . . . . . . Welder Qualification . . . . . . . . . . . . . . . . . . . . . . . . .

1.1 1.1 1.1 1.1 1.2

TEST METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . Non-Destructive Examination . . . . . . . . . . . . . . . . . . Destructive Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FIGURE 2.1 SURFACE BUILD-UP DETAILS OF SIDE BEND TEST SPECIMEN . . . . FIGURE 2.2 PROCEDURE QUALIFICATION TRANSVERSE TENSILE TEST PIECE . . . . . . . . . FIGURE 2.3 PROCEDURE QUALIFICATION ALL WELD TENSILE TEST PIECE . . . . . . . . . . . FIGURE 2.4 WELDER AND PROCEDURE QUALIFICATION SIDE BEND PIECE . . . . . . . . . . . . . . . . . . . . . . . . . .

2.1 2.1 2.1

1. 1.1 1.2 1.3 1.4

1.5 SECTION

2. 2.1 2.2

1.3

1.4 1.5

2.2 2.3 2.4

2.5

SECTION

3. 3.1 3.2

ACCEPTANCE STANDARDS . . . . . . . . . . . . . . . . . Non-Destructive Examination . . . . . . . . . . . . . . . . . . Destructive Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TABLE 3.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.1 3.1 3.1 3.1

SECTION

4.

RETESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.1

vii

NES 825 Issue 2 (Reformatted)

SECTION

5. 5.1 5.2 5.3 5.4 5.5 5.6

WELD REPAIR OF CASTINGS . . . . . . . . . . . . . . . Welding Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . General Welding Requirements . . . . . . . . . . . . . . . . Temperature Measurement . . . . . . . . . . . . . . . . . . . . Heat Treatment of Weld Repairs . . . . . . . . . . . . . . . Approved Processes . . . . . . . . . . . . . . . . . . . . . . . . . . Approved Welding Consumables . . . . . . . . . . . . . . .

5.1 5.1 5.2 5.3 5.3 5.3 5.3

SECTION

6.

NON-DESTRUCTIVE EXAMINATION OF CASTING WELD REPAIRS . . . . . . . . . . . . . . . . . . . Visual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dye Penetrant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Radiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.1 6.1 6.1 6.1

7.1 7.2 7.3

ACCEPTANCE STANDARDS FOR CASTING WELD REPAIRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . Visual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dye Penetrant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Radiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7.1 7.1 7.1 7.1

SECTION

8.

RECORDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8.1

SECTION

9.

9.1

9.2 9.3 9.4 9.4.1 9.5 9.6 9.7 9.8 9.8.1 9.8.2 9.8.3 9.8.4 9.9 9.10

PROCUREMENT OF WELDING WIRE . . . . . . . . TABLE 9.1 CHEMICAL COMPOSITION OF WELDING WIRE . . . . . . . . . . . . . . . . . . . . . . . . . . . Dimensions and Tolerances . . . . . . . . . . . . . . . . . . . . TABLE 9.2 TOLERANCES ON ROUND WIRE . . Condition of Materials . . . . . . . . . . . . . . . . . . . . . . . . Quality Assurance Documentation . . . . . . . . . . . . . . Test Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Free Coil and Helix Test (Spooled Wire Only) . . . . Welding Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Non-Destructive Test . . . . . . . . . . . . . . . . . . . . . . . . . Acceptance Standards . . . . . . . . . . . . . . . . . . . . . . . . Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Free Coil and Helix . . . . . . . . . . . . . . . . . . . . . . . . . . . Welding Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . Non-Destructive Examination . . . . . . . . . . . . . . . . . . Identification Markings . . . . . . . . . . . . . . . . . . . . . . . Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ANNEX

A.

RELATED DOCUMENTS . . . . . . . . . . . . . . . . . . . .

A.1

ANNEX

B.

DEFINITIONS AND ABBREVIATIONS . . . . . . . .

B.1

6.1 6.2 6.3 SECTION

7.

9.1

ALPHABETICAL INDEX

viii

9.2 9.2 9.3 9.3 9.3 9.3 9.3 9.3 9.4 9.4 9.4 9.4 9.4 9.4 9.4 9.4 9.5

NES 825 Issue 2 (Reformatted)

1.

QUALIFICATION REQUIREMENTS

1.1

Weld Procedure a.

All welding is to be carried out to approved welding procedures for each welding  process or combination of welding processes concerned. Weld procedures, complete with the test results, are to be submitted through the QAR to the Design Authority for approval.

b.

Written weld procedures are to be prepared embodying the relevant information from this NES and are to include all information required to complete sound welds including the following:

c.

1.2

Parent Material identity and size.

(2)

Welding Process or combination of welding processes.

(3)

Welding Process Parameters as follows: (a)

Welding position;

(b)

Welding consumables, identity and specification;

(c)

Sketch of weld preparation;

(d)

Welding characteristics including voltage amperage and polarity;

(e)

Pre-heat and interpass temperatures;

(f)

Deposition sequence;

(g)

Shielding gas composition and flow rate;

(h)

Cleaning procedures;

(i)

Heat Treatment;

(j)

NDT and acceptance standard.

In accordance with NES 824 Part 1 Clause 1305 surface and sub-surface weld repairs to castings will be considered on a concession basis. Prior to any weld repairs being undertaken weld procedures are to be qualified as follows:

Repair by Surface Build-Up a.

1.3

(1)

A piece of cast material of minimum size 320mm ¢ 125mm ¢ 25mm thick is to be built up under restraint with weld metal to a thickness of approximately 7mm in accordance with FIGURE 1.1.

Repair of Sub-Surface Defects a.

A piece of cast material of minimum size 320mm ¢ 250mm ¢ 40mm thick with an excavated groove in accordance with FIGURE 1.2 is to be welded under restraint.

1.1

NES 825 Issue 2 (Reformatted)

1.4

Repair Simulation a.

In addition to 1.2a. and 1.3a. above it is permissible to simulate a proposed weld repair in a particular casting by using a cast test plate machined to reproduce the actual casting wall thickness and repair to be undertaken. The test piece is to embody, as far as possible, all essential features regarding restraint, access and heat sink. Post weld NDT and destructive testing is to align with 1.2a. or 1.3a. above as appropriate.

Note: b.

Size of test plates may be increased to suit local tensile testing facilities. The following requirements apply: (1)

Prior to welding the test plate is to be heat treated in a furnace validated in accordance with NES 746 by: (a)

Preferably heat treating with the associated castings during stress relief.

or (b)

Separately by placing in a furnace with temperature not higher than 100° C, raising to 450° C to 500° C at a maximum rate of 200° C/hour, soaking for two hours and then air cooling.

(2)

The test plate is to be dye penetrant checked and radiographed, after heat treatment and prior to welding, to ensure cast-in-defects are identified and do not subsequently cause rejection of the test weld.

(3)

The test plate is to be welded under restraint in accordance with the proposed welding procedure.

(4)

On completion of welding the test piece is to be non-destructively examined in accordance with Sections 2. and 3.

(5)

If the examination at (4) is satisfactory the test plate is to be heat treated again in accordance with Clause 1.4b.

(6)

On completion of (5) the test plate is to be non-destructively re-examined in accordance with Sections 2. and 7.

(7)

Subject to satisfactory final non-destructive results, in accordance with Clause 3.1a., the test piece is to be marked with the positions of  destructive test specimens. Mechanical tests are to be carried out in accordance with Clauses 2.2a. to 2.2c., as appropriate, and results are to meet the requirements of Clause 3.2a.

1.2

NES 825 Issue 2 (Reformatted)

FIGURE 1.1 SURFACE BUILD-UP WELDER AND PROCEDURE QUALIFICATION TEST PIECE

1.3

NES 825 Issue 2 (Reformatted)

FIGURE 1.2 SUB-SURFACE REPAIR WELDER AND PROCEDURE QUALIFICATION POSITION OF TEST SPECIMENS

1.4

NES 825 Issue 2 (Reformatted)

1.5

Welder Qualification a.

Each welder is to be qualified to meet the appropriate acceptance standard using the approved welding procedures. No welder is to be employed on work requiring an acceptance standard beyond his proven capabilities.

b.

The contractor is responsible for qualifying each welder by ensuring that he is capable of working strictly to the welding procedures under production conditions to the relevant acceptance standards. The contractor is to ensure that welders maintain the required standard by checking their work as a result of the normal production non-destructive testing.

c.

Where a welder is unable consistently to meet the acceptance standards or fails to work in accordance with the approved procedure, he is not to be employed on Ministry work. Re-establishment of the welder qualification is subject to acceptance by the QAR.

d.

Welder qualification test assemblies are to be chosen from those detailed in Clause 1.1c.

e.

Qualification of a welder is accepted if the visual, dye penetrant and radiographic examinations meet the requirements of Clause 3.1a. and the side bend test and macro specimen tests meet the requirements of Clause 3.2a.

f.

Requalification of welders is required if: (1)

the Acceptance Authority has reason to doubt that the standard or workmanship in production does not meet the requirements of this NES; or

(2) g.

a period of six months has elapsed since the welder was last engaged on welding the material to the acceptance standards required by this NES.

Weld procedures and welders may be qualified simultaneously.

1.5

NES 825 Issue 2 (Reformatted)

1.6

NES 825 Issue 2 (Reformatted)

2.

TEST METHODS

2.1

Non-Destructive Examination a.

2.2

On completion of welding and again after subsequent heat treatment the test plates are to be non-destructively examined in accordance with Section 6.

Destructive Tests a.

The following mechanical tests are to be carried out in accordance with BS 18 and BS 4206 as appropriate.

b.

Surf ace Bui ld-Up

c.

(1)

Side Bend Tests (See FIGURE 1.1 and FIGURE 2.1)

(2)

Macro Specimen (¢10 Magnification) (See FIGURE 1.1)

Sub-Surface R epair (1)

Transverse Tensile Test (see FIGURE 1.2 and FIGURE 2.2)

(2)

All Weld Metal Tensile Test (see FIGURE 1.2 and FIGURE 2.3)

(3)

Side Bend Test (see FIGURE 1.2 and FIGURE 2.4)

(4)

Macro Section (¢10 Magnification) (See FIGURE 1.2)

2.1

NES 825 Issue 2 (Reformatted)

FIGURE 2.1 SURFACE BUILD-UP DETAILS OF SIDE BEND TEST SPECIMEN

2.2

NES 825 Issue 2 (Reformatted)

FIGURE 2.2 PROCEDURE QUALIFICATION TRANSVERSE TENSILE TEST PIECE

2.3

NES 825 Issue 2 (Reformatted)

FIGURE 2.3 PROCEDURE QUALIFICATION ALL WELD TENSILE TEST PIECE

2.4

NES 825 Issue 2 (Reformatted)

FIGURE 2.4 WELDER AND PROCEDURE QUALIFICATION SIDE BEND PIECE

2.5

NES 825 Issue 2 (Reformatted)

2.6

NES 825 Issue 2 (Reformatted)

3.

ACCEPTANCE STANDARDS

3.1

Non-Destructive Examination a.

3.2

All results are to meet the requirements detailed in Section 7. on the basis that the weld is in a Critical Test Region.

Destructive Tests a.

The acceptance standards for destructive tests are as follows: (1) Mechanical test results are to be equal to or greater than the figures specified below: UTS I N/mm2

0.2% Proof  Stress N/mm2

Elongation 5.65!S 0 Gauge Length %

Transverse Tensile Test (See Note)

480

!

!

 All Weld Metal Tensile Test

480

300

18

TABLE 3.1

NOTE:(1) Report location of the fracture, whether weld, heat affected zone or parent metal. If fracture in parent metal, its approximate distance from weld fusion line to be stated. Record also type and location of any flaws present on fractured surfaces. (2) The side bend test is to be accomplished through 180° over a 40mm(5t) diameter mandrel without total fracture. The maximum acceptable cracks at 180° are 3mm in any direction in the weld metal, HAZ or fusion zone. Cracks originating at weld bead undercuts, at slag inclusions or at casting defects will not be cause for rejection. (3) The macro specimen is to be rejected if cracks or tears are visible in the weld or heat affected zone. Cracks originating at casting defects in the parent material will not be cause for rejection.

3.1

NES 825 Issue 2 (Reformatted)

3.2

NES 825 Issue 2 (Reformatted)

4.

RETESTS a.

In the event of failure of test specimens to meet the acceptance standards detailed in Section 3., retest procedure is to be as follows: (1)

Where a test weldment fails to meet the non-destructive examination requirements, a new assembly is to be made and tested;

(2)

Where a test weldment fails to meet the destructive test requirements two further test weldments are to be made and tested and both test weldments are to meet requirements.

b.

Where the test weldment fails to meet the required mechanical or physical properties after retest, the procedure is to be rejected.

c.

For any change in an approved weld procedure to be agreed, requalification of  the procedure is to be carried out.

4.1

NES 825 Issue 2 (Reformatted)

4.2

NES 825 Issue 2 (Reformatted)

5.

WELD REPAIR OF CASTINGS a.

No welding is to be undertaken on castings until a concession has been approved in accordance with the requirements of NES 824 Part 1 Section 13. Concessions submitted for consideration are to include: (1)

Full details of the proposed method of repair including the approved welding procedure(s) to be used and confirmation that the weldability test defined in NES 824 Part 1 Clause 1104 has been satisfactory completed and

(2)

b.

5.1

Sketches of the proposed repair indicating the position, nature, extent and depth of defects, design wall thickness of the area and thickness of the original parent material remaining.

The extent of excavations and subsequent weld repair is to be only that necessary to bring the casting within the acceptance standards of NES 824 Part 1 Section 12. The extent of weld repair is to be limited in accordance with the following clauses.

Welding Limitations a.

The rectification of defects by welding is not permitted on any sea water wetted surface. See also NES 824 Part 1 Clause 1304.

b.

Defects may only be rectified when, after removal of the defect, excavation depth does not penetrate to within 10mm of the wetted surface. See also NES 824 Part 1 Clause 1305.

c.

Corrections to casting dimensions and machining errors by surface build-up will be considered providing the following finished limits are not exceeded. (1)

5mm maximum build up for wall thicknesses 25mm and under.

(2)

20% of wall thickness maximum build up for wall thicknesses over 25mm but must not exceed 10mm.

(3)

Area of build up on Class I and Class II castings (see NES 824 Pt 1 Section 7 for definitions) is to be restricted to 10% of the inner or outer surface area not including flange thicknesses and webs, subject to any further limitations imposed by Clause 5.1g.

(4)

Areas of build up on Class III castings are to be restricted to 20% of the inner or outer surface area not including flange thickness and webs.

d.

Unacceptable surface or near surface defects is to be blended out in accordance with NES 824 Clause 1311.

e.

Defects which cannot be blended out within the required limits are to be treated as sub-surface defects.

f.

Any individual sub-surface repair in a Critical Test Region is not to exceed 5% of the test area containing the defect. In Test Regions any individual repair is not to exceed 10% of the test area containing the defect.

5.1

NES 825 Issue 2 (Reformatted)

g.

The total combined area of weld repairs from all causes, eg dimensional corrections, machining errors and sub-surface is not to exceed; (1)

10% of Critical Test Regions

and (2) h.

20% of Test Regions and non-designated areas of Class III castings.

When repairs are required which are more extensive than permitted by Clauses 5.1a. to 5.1g. then the casting is to be either: (1)

Scrapped

or (2)

5.2

A special concession submitted which defines the extension of weld repair beyond the permitted limits and clearly explains the reasons why such repairs are necessary.

General Welding Requirements a.

Defects are to be removed by machining or pneumatic chipping and grinding. Excavation of defects is to commence in sound material at the ends of the defects and proceed from each end towards the centre.

b.

Excavations are to be finished smooth, tapered at the sides and rounded at the bottom to facilitate full access for the root run and correct manipulation of the filler wire.

c.

Before weld action is undertaken a thorough examination of the excavated area  is to be made using radiography and dye penetrant methods to ensure adequate removal of the defect.

d.

Prior to the deposition of weld material, all contaminants resulting from non-destructive examination are to be removed with lint free cloth using  acetone or the approved solvent remover for the dye penetrant system used.

e.

Interpass cleaning is to be carried out using a stainless steel wire brush which has not been used on any other material.

f.

Interpass grinding, when necessary, is to be carried out with resin bonded alumina grinding wheels or with tungsten carbide burrs.

g.

All welding is to be carried out in the ‘Flat Position’ in accordance with the definitions given in BS 499 Part 1.

h.

In order to achieve satisfactory results it is essential that the instructions detailed in this NES are followed in all repairs to castings and are incorporated in the appropriate weld procedures.

i.

Stop and start porosity or deep end craters are tobe minimized byuse of the‘run back technique’ as appropriate to the welding process being used. This technique is a means of avoiding porosity and crater cracking which can be caused bythe abrupt withdrawal ofthe welding arc atthe end of a weld run. This technique consists of delaying the consumable at the weld end to fill the crater and then welding back along the top of the previously deposited weld for a short distance, thus facilitating the withdrawal of the arc from superfluous weld metal which is subsequently removed.

5.2

NES 825 Issue 2 (Reformatted)

5.3

 j.

Where necessary, extension ‘run-on’ and ‘run-off’ plates of the same material as that to be welded are to be securely welded to the component and grooved to conform to the actual weld preparation. For the repair of excavations wedge shaped ‘run-on’ and run-off’ plates may be used.

k.

When large areas of weld repair are involved, the weld metal is to be deposited in such a manner that the final weld pass consists of weld metal to weld metal.

l.

If a casting repair is unsuccessful and the ‘repair’ requires to be rewelded, not more than two rewelds are permitted.

m.

The interpass temperature during welding is not to exceed 150° C.

Temperature Measurement a.

5.4

Heat Treatment of Weld Repairs a.

NOTE

5.5

After weld repair all castings are to be heat treated by placing them in a furnace with temperature not higher than 100° C, raising to 450° C to 500° C at a  maximum rate of 200° C/hr, holding for 1 hour per 25mm thickness (minimum period 2 hours) and then air cooling. The furnace is to be validated in accordance with NES 746. The heat treatment requirement for weld repaired areas described above is in addition to the mandatory ‘Stress Relief’ heat treatment which is required for all Copper Nickel Chromium castings in accordance with NES 824 Part 1.

Approved Processes a.

5.6

Interpass temperature is to be determined by contact pyrometers or thermocouples; the use of low melting metallic alloys or any temperature indicating crayons or paints is prohibited.

Welding may be carried out with TIG, MIG, Pulsed MIG or a combination of  these processes.

Approved Welding Consumables a.

All approved welding consumables are to be readily identifiable so that they can be positively related to their Quality Assurance documentation.

5.3

NES 825 Issue 2 (Reformatted)

5.4

NES 825 Issue 2 (Reformatted)

6.

NON-DESTRUCTIVE EXAMINATION OF CASTING WELD REPAIRS a.

6.1

Visual a.

6.2

The surfaces of all welds are to be inspected visually before any other means of  non-destructive examination. Visual aids such as magnifying lenses ( ¢10) and strong lights are to be used to quantify defects. All imperfections are to be identified and recorded.

Dye Penetrant a.

6.3

All castings which have been weld repaired are to be inspected, after heat treatment, as detailed below. Non-destructive examination methods are to be in accordance with NES 729 Part 1 and Part 4 where appropriate.

All weld repair and weld build-up areas are to be examined in accordance with the procedures defined in NES 729 Part 4. Examinations are to be conducted after grinding or machining the weld surfaces to the required profile.

Radiography a.

All weld repairs are to be radiographed in accordance with the procedures defined in NES 729 Part 1 and adherence to sections 20 and 21 is of particular importance. It is preferred that X Ray is used wherever practicable. All subsurface imperfections are to be identified for subsequent assessment.

6.1

NES 825 Issue 2 (Reformatted)

6.2

NES 825 Issue 2 (Reformatted)

7.

ACCEPTANCE STANDARDS FOR CASTING WELD REPAIRS a.

7.1

Visual a.

7.2

The welds and adjacent parent material is to be free from scale, slag, weld spatter and arc strikes. The weld is to be of regular surface appearance, ie free from globular deposits and sharp discontinuities and surface breaking porosity. Edges of weld are to blend smoothly and gradually into the parent material. The depth of local undercut or depression resulting from blending is not to exceed 1mm.

Dye Penetrant a.

7.3

The minimum acceptance standards for casting weld repairs are defined in Clauses 7.1a. to 7.3d.

The welds and adjacent material are to meet the acceptance standards defined in NES 824 Part 1 Clause 1206.

Radiography a.

Cracks and lack of fusion are not acceptable. The maximum length of any single linear inclusion is not to exceed one half of the design wall thickness in way of  the inclusion. Such inclusions are to be separated by at least: (1)

2.25 times the thickness of the material in way of the defect.

or (2)

1.25 times the length of the larger adjacent defect.

b.

If however the distance between the ends of two defects or defective areas is less than either of the above values, they are to be considered as a single defect showing an overall length equal to the distance measured between the extremities of the defects or defective areas.

c.

The total length of inclusions is not to exceed 20% of the maximum dimension of the area affected by the weld repair.

d.

Loss of wall thickness from localized internal porosity is not to exceed 5% of the designated wall thickess in Critical Test Regions and 10% in Test Regions and non-designated areas.

7.1

NES 825 Issue 2 (Reformatted)

7.2

NES 825 Issue 2 (Reformatted)

8.

RECORDS a.

The contractor is to be responsible for maintaining records of all welding carried out within the scope of this NES. These are to include: (1)

Welder qualification.

(2)

Procedure qualification.

(3)

Full fabrication details if appropriate.

(4)

Weld history sheet.

(5)

Details, including accurate sketches, showing location and depth of all weld repairs.

(6)

Record of heat treatment.

(7)

Record of weld repair inspection results.

(8)

Record of material weldability test.

(9)

Cast number.

8.1

NES 825 Issue 2 (Reformatted)

8.2

NES 825 Issue 2 (Reformatted)

9.

PROCUREMENT OF WELDING WIRE a.

Welding wire is to conform to the chemical composition detailed in TABLE 9.1.  Wire is to be drawn from billets which have been produced in a vacuum induction furnace from virgin metals or master alloys as follows; (1)

Nickel

to the chemical composition requirements of BS 375. Grade R99.95A or R99.95B.

(2)

Copper

to BS 6017 Designate Cu!CATH!1.

(3)

Manganese

99.9% minimum purity electrolytic manganese flake.

(4)

Silicon

high purity lump silicon (0.3% iron maximum).

(5)

Chromium

99.5% minimum purity electrolytic or thermic chrome.

(6)

Titanium

pure titanium sponge or other solid form, high purity copper-titanium master alloy or high purity nickel-titanium master alloy.

(7)

Zirconium

high purity copper-zirconium master alloy or high purity nickel-zircomium master alloy.

Notes 1.

Contamination by carbon pick-up can be substantially reduced by using  rammed basic linings for electric furnaces and using an alumina wash on ladles. Finishing additions such as magnesium or calcium are not to be used. No further additions are to be made to the melt after the final analytical sample has been taken.

2.

The specification for welding wire defined is under review. Please contact NA 133 prior to procurement of welding wire to this NES.

9.1

NES 825 Issue 2 (Reformatted)

PER CENT BY WEIGHT NOT LESS THAN

NOT MORE THAN

29.00

32.00

Chromium

2.0

2.4

Manganese

1.4

2.0

Silicon

0.20

0.40

Zirconium

0.05

0.15

Titanium

0.1

0.20

Nickel

Copper

Remainder

IMPURITIES Iron

!

 

0.05

Lead

!

 

0.0015

Phosphorous

!

 

0.005

Bismuth

!

 

0.0005

Sulphur

!

 

0.003

Carbon

!

 

0.006

Cobalt

!

 

0.020

Boron

!

 

0.001

Selenium

!

 

0.0005

Tellurium

!

 

0.0005

 Arsenic

!

 

0.0010

Zinc

!

 

0.0020

Total Impurities

!

 

0.060

TABLE 9.1 CHEMICAL COMPOSITION OF WELDING WIRE

9.1

Dimensions and Tolerances a.

The diameter of the wire is to be determined by means of a suitable micrometer taking the mean of two measurements at right angles made at the same cross section of a sample taken from any part of the spool or when supplied in one metre lengths any position on a random sample from each batch.

b.

The difference between the maximum and minimum measurements, taken at the same cross section is not to exceed the amounts specified in TABLE 9.2.

9.2

NES 825 Issue 2 (Reformatted)

Specified Diameter Over

Up to and including 

Tolerance

Difference between max and min measurements not to exceed

mm

mm

mm

mm

0.7

2.00

+0.01 !0.04

0.02

+0.01 !0.07

0.02

2.00

5.00 TABLE 9.2 TOLERANCES ON ROUND WIRE

9.2

9.3

Condition of Materials a.

All reeled wire is to be supplied in a cold drawn condition suitable for use in standard MIG Welding Equipment. If during manufacture the wire is fully annealed, attention is drawn to the material’s ductility trough in the 600° !700° C temperature range.

b.

There are to be no joints in the wire.

c.

The wire is to be supplied in a clean condition with the oxide layers removed by a mechanical process such as diamond shaving or chemical etching process.

d.

The wire is to be free from oil, dirt, grease, chemical contamination or other foreign matter which would adversely affect the quality of the weld.

e.

The wire is to be supplied in one metre straight lengths for rod or on spools with the wire precision layer wound. The size of the spool is to be 300mm diameter or as agreed for each contract of supply.

f.

Spooled wire is to be closely wound in layers so that it is free from kinks, waves or sharp bends and can be unwound without restrictions caused by overlapping  or wedging. The outside end of the wound wire is to be securely fastened at a  readily located point.

g.

Each batch of wire is to be given a unique number which relates it unambiguously to the extrusion billet from which it was manufactured. Only one extrusion billet is to be used for each batch of finished wire.

Quality Assurance Documentation a.

Each consignment of wire is to be accompanied by Quality Assurance Documentation giving the actual results of the tests required by Clauses 9.4.1a.!9.7b. together with certificates of compliance with the relevant acceptance standards detailed in Clauses 9.8.1a.!9.8.4b.

9.4

Test Methods

9.4.1

Analysis

a.

9.5

A full analysis is to be made from a sample of the finished wire from each batch. The analysis is to be recorded.

Free Coil and Helix Test (Spooled Wire Only) a.

A length of wire sufficient to form at least a 11 / 8 loop is to be cut and removed from a spool of wire taken at random, to represent the batch. The wire is to be allowed to freely unwind from the spool without any undue effort being applied so that it forms a free coil. The coil is to be placed on a flat surface and the diameter and pitch (vertical wire separation) recorded.

9.3

NES 825 Issue 2 (Reformatted)

9.6

Welding Test a.

9.7

Each batch of wire, spooled or straight lengths, is to be tested for weldability by using a random sample of wire, to represent the batch. The wire is to be deposited on a 70/30 Cupro Nickel plate of approximately 12mm thickness so that three beads 100mm long are laid parallel with each other, the third bead being superimposed over the other two beads. The test weld is to be radiographed in accordance with NES 729 Part 1.

Non-Destructive Test a.

The surface of the wire isto be examined, under clean conditions, in the supplied condition before sealing and packaging. Any indications of oxides staining, variations in colour or surface roughness are to be recorded.

b.

The outside end of each spool of wire and one straight length from each package are to be dimensionally checked and the results recorded.

9.8

Acceptance Standards

9.8.1

Analysis

a.

9.8.2

Free Coil and Helix

a.

9.8.3

9.9

For 300mm diameter spools the diameter of the coil measured in Clause 9.5a. is to be 380mm minimum and 760mm maximum and vertical separation of the wire (pitch) is not to exceed 25mm. For other sizes of spools the dimensional limitations are to be as stated in the Contract for supply.

Welding Standard

a.

9.8.4

The chemical analyses are to conform to TABLE 9.1. Any wire failing to meet the chemical composition detailed in TABLE 9.1 is to be rejected together with all other wire from the same batch.

The radiographs produced in accordance with Clause 9.6a. are to be examined in accordance with NES 729 Pt 1 and are to be free from indications of porosity, cracking or inclusions.

Non-Destructive Examination

a.

The wire examined in accordance with Clause 9.7a. is to be rejected if there is any evidence of discoloration, surface roughness, oxide, scale, grease, oil or any loose contamination.

b.

The dimension of the wire tested in accordance with Clause 9.7b. is to be within the tolerances stated in TABLE 9.2 and to the diameter specified in the Contract Documents.

Identification Markings a.

For identification purposes all spools and packages containing copper nickel chromium wire to this NES are to be legibly marked by the manufacturer in letters not less than 5mm in height, with the following particulars: (1)

The unique material batch number used for all quality assurance documentation associated with this spool or package wire together with the reference CUNICR and specification NES 825.

(2)

Size and weight of wire on spool.

(3)

Manufacturer.

9.4

NES 825 Issue 2 (Reformatted)

9.10

Packaging a.

Except where otherwise stated in the Contract Documents all reeled wire is to be supplied on spools sealed in a plastic envelope for complete protection and cleanliness. The sealed spools are to be contained in stout cardboard or wooden boxes. Straight lengths are to be supplied in sealed packages of 2kg each.

9.5

NES 825 Issue 2 (Reformatted)

9.6

NES 825 Issue 2 (Reformatted)

ANNEX A. RELATED DOCUMENTS A.1

Reference is made to: Referred to in Clause BS 18

Tensile testing of metals (including  aerospace materials)

BS 375

Refined nickel

9.a.

BS 499 Pt 1

Welding terms and symbols— Pt 1—Glossary for welding, brazing  and thermal cutting 

5.2g.

BS 4206

Methods of testing fusion welds in copper and copper alloys

BS 6017

Copper refinery shapes

NES 729 Pt 1

Requirements for Non-destructive Examination Methods— Pt 1—Radiographic

Pt 4

Pt 4—Liquid Penetrant

NES 746

Approval and Control of Heat Treatment Furnaces

NES 824 Pt 1

Requirements for the Production of  Copper-Nickel Chromium Sand Castings and Ingots

A.1

2.2a., FIGURE 2.3

2.2a., FIGURE 2.2 9.a. 6.a., 6.3a., 9.6a.

6.a., 6.2a. 1.4b., 5.4a. SCOPE 1., 1.1c., 5.a., 5.b., 5.1a., 5.1b., 5.1d., 5.4a., 7.2a.

ANNEX A.

NES 825 Issue 2 (Reformatted)

ANNEX A.

A.2

NES 825 Issue 2 (Reformatted)

ANNEX B. DEFINITIONS AND ABBREVIATIONS B.1

For the purpose of this NES the following definitions apply:  Acceptance Authority

the Design Authority for the system concerned;

Contractor

the Firm, Organization, Establishment or HM Naval Base working within the scope of this NES;

Design Authority

the relevant Section of the Sea System Controllerate responsible for the systems concerned;

Interpass Temperature

in a multi-run weld, the interpass temperature is defined as ‘the temperature of the weld and adjacent parent metal, immediately prior to the application of the next run’. Interpass temperature is to be measured on the surface of  the base material on the side from which welding  is to be performed, within 25mm of the weld joint edge;

Quality Assurance Representative (QAR)

the MOD(PE) personnel engaged in ensuring that the requirement of this NES are being met.

B.1

ANNEX B.

NES 825 Issue 2 (Reformatted)

ANNEX B.

B.2

NES 825 Issue 2 (Reformatted)

ALPHABETICAL INDEX

A Analysis, 9.3, 9.4 Approved processes, 5.3 Approved welding consumables, 5.3 Approved welding procedures, 1.1

C Certificate of compliance, 9.3 Chemical composition, 9.1 Clean condition of wire, 9.3 Concessions, 5.1, 5.2 Contamination by carbon, 9.1

D Defects, 5.1 Destructive acceptance standards, 3.1 D estructive tests, 2.1, 3.1 D ye penetrant, 1.2, 5.2, 6.1

F Free coil and Helix test, 9.3

H H eat treat ment, 1.1, 1.2, 2.1, 5.3, 6.1 Helix test, 9.3

I Interpass temperature, 5.3, B.1

L Limitation of weld repair, 5.1, 5.2, 9.4

M Markings, identification, 9.4 Mechanical test results, 3.1 Mechanical tests, 2.1

INDEX.1

INDEX

NES 825 Issue 2 (Reformatted)

N Non-destructive acceptance standards, 3.1, 7.1 Non-destructive tests, 2.1

P Post weld heat treatment, 1.2

Q Qualification of welders, 1.3 Quality assurance documentation, 9.3

R Radiography, 1.2, 5.2, 6.1, 7.1 Repairs, 1.1, 5.1 Retests, 4.1

S Side bend test, 2.1

T Tempera ture me asurement , 5.3 Tensile test , 2.1, 3.1 Test pieces, 1.1 Tolera nces o n wire, 9.2

V Virgin met als, 9.1

W Weld procedures, 1.1, 5.1 Weld repairs, 5.1, 5.2 Welder q ualifications, 1.3 Welding consumables, 5.3 Welding process, 1.1, 5.3 Welding test of wire, 9.4 Welding wire, 9.1

INDEX

INDEX.2

 Inside Rear Cover