Attachment_0036_GDLS-C_Field_Weld_Repair_Procedure_F-4000_Rev_L.pdf

Repair Procedure F-4000

GENERAL DYNAMICS

LAND SYSTEMS – CANADA CORPORATION

LONDON ONTARIO

FIELD WELD REPAIR PROCEDURE

F-4000

PREPARED BY: E. TRUCHANOWICZ

INDEX

PAGE

REVISION RECORD SHEET 3

1) PURPOSE AND SCOPE 4

2) PERSONNEL REQUIREMENTS, WELDING REPAIR 4

3) EQUIPMENT CONDITIONS, WELDING REPAIR 4

4) CRACK IDENTIFICATION, WELDING REPAIR 5

5) CRACK ARRESTING, WELDING REPAIR 5

6) WELDING REPAIR PROCEDURES 10

7) WELDING TECHNIQUES, PRACTICES AND PROCEDURES 33

8) SPALL LINER FIELD REPAIR PROCEDURE 44

APPENDIX A: INSPECTION STANDARDS FOR 57

COMPLETED REPAIR WELDS

APPENDIX B: LIQUID PENETRANT INSPECTION 60

APPENDIX C: STYKER BCT SPALL LINER ACCEPTANCE CRITERIA

BATTLE DAMAGE/RESET VEHICLES ONLY. 63

APPENDIX D: DVH HULL WELDED 77

DVH LOWER HULL REPAIR GUIDANCE 81

REVISION RECORD

Approvals

Rev.

Page(s) Description ECO # Issued By Approved By

NR All New CDN-013 ET BJ

A All Update to par.6 22299 ET BJ

B 42-44

Added new par. 7

Update to par.6 proc.H-K

24052 ET

TM

BJ

C 26

Procedure “G” updated

Content updated

Added new Appendix 2

33376

ET

TM

TM

BJ

D ALL Content updated 39117 ET BJ

E 4,18, 27, 14-16 Content updated 42687 ET BJ

F 46,48, 51,52, 54,55

Section 8 updated

(MEK solvent eliminated)

44195 ET

RH

BJ

G 3

Revision record updated

Procedure "G" updated (option that the original spall liner can be left in place after weld repairs on the outside of the hull is removed)

Vinyl wash can not be used on BCT/USMC contracts

Vinyl wash can not be used on BCT/USMC contracts

90793 ET BJ

H 46, 48, 51,52,54,56

New solvent added, Appendix 3 94222 ET BJ

J 2,3,4,33,45,63, Added DVH weld guidance and appendix C (spall acceptance criteria)

100688 JK BJ

K 4

81-87

- Added CMS 18 and CMS 19 to Armor Steel list

- Added DVH A514 repair guidance to appendix D

104297 JK BJ

L 3

-Revision Record Updated

-Added spall inspection methodology

-Updated table: oversize, unequal fillets

CCR-

00000219

JR BJ

1) PURPOSE AND SCOPE

The purpose of this procedure is to provide instructions/guidelines to weld repair non-conformances and cracks in base metals or welds in armor steels* and carbon/low-alloy structural steels** in a field environment. The scope of this procedure includes the welding techniques*** for repair, removal/replacement of the weld metal and the base metal of the installed equipment. The scope also includes removal and replacement of damaged spall liner panels.

Armor steels *– MIL-A-46100 (GDLS CMS-18), MIL-A-12560 (GDLS CMS-19), MIL-A-46177

(GDLS CMS-19)

Carbon/Low-Alloy structural steels ** - ASTM A36, ASTM A108, ASTM A322 GRADE 8620, ASTM

A514, ASTM A572 GRADE 50, ASTM A710, CSA G40.21 GRADE44W/50W or other approved by the

Engineer.

Welding techniques*** - Appendix D provides DVH Welding Guidance

2) PERSONNEL REQUIREMENT, WELDING REPAIR

Only a welder qualified in accordance with GDLS-C Welder Qualification Procedure D-0040 (field service section) shall be allowed to perform the field repair work.

Every welder engaged in the welding operations specified in this field repair procedure has to possess current certification per D-0040.

All personnel involved in the repair procedure are required to wear protective clothing as well as apron, gloves, helmet and goggles when performing arc-air gouging, welding and grinding. Failure to do so may result in serious injury. All involved personnel shall receive basic training in safety of welding and cutting operations.

3) EQUIPMENT CONDITIONS, WELDING REPAIR

Prior to the start of any repair work, the vehicle will be parked, the parking brake applied, transmission shifted to "N" and the engine turned off.

The ground cable will be disconnected from the battery and sensitive electrical circuitry disconnected from the component to be repaired (example, weapon stations). If possible, sensitive equipment (ie.

electronics) shall be disassembled prior to start of repair, and safely stored.

The welding machine ground cable will be applied as close as possible to the repair area on a clean metal surface (prime and paint removed by a suitable mechanical method).

Prior to any hole burning/drilling or weld repair, remove or protect all the components that can suffer damage during the repair process.

4) CRACK IDENTIFICATION, WELDING REPAIR

A crack is defined as a fracture type discontinuity characterized by a sharp tip(s) and high ratio of length to width and opening displacement.

5) CRACK ARRESTING, WELDING REPAIR

In order to stop a crack from further propagation, immediate action shall be taken to arrest the crack at the initial shape and size.

To securely arrest the crack, the following procedure shall be applied:

a) Remove all paint by scraping or sanding the area 15mm wide from both sides of the crack.

b) Positively identify crack end(s), using the Liquid Penetrant Inspection (PT) method, see Appendix

A.

c) Using arc-air gouging equipment, burn a through hole, 3 to 5mm in diameter at the crack end(s), see Figure 1. If an arc-air gouge method is not available, drilling a through hole is an allowed optional method. To drill the hole, an armor piercing drill is required. The centre of the hole shall be located as close as possible over the tip of the crack as shown on Figure 1A. If the hole was burnt by using arc-air gouging process, both edges of the hole shall have burrs removed before proceeding with repair.

d) Using Liquid Penetrant, inspect the burnt/drilled hole to make sure the hole was burnt/drilled at the tip of the crack and crack does not propagate beyond the hole. Radiography can be used as an optional method. If the crack propagates beyond burnt/drilled hole, repeat steps b), c) and d).

Figure 1A

Location of Crack Arresting Hole

Figure 1

Crack Arresting Procedure

e) If the hole cannot be burnt or drilled immediately after discovery for whatever reason, the crack can be arrested by means of a temporary horse shoe shaped weld, laid around the crack, as shown on

Figure 2.

Figure 2

Temporary Horse Shoe Weld

Hole(s) will be burnt/drilled and a horse shoe shaped weld ground flush with parent metal contour at earliest convenience.

f) If crack opening exceeds 2mm, restraining welds will be applied as per Figure 3 to prevent opening from getting any larger. If welds are applied as per Figure 3, they will be applied before crack arresting holes are burnt/drilled.

Figure 3

Temporary Crack Width Stabilizing Welds

Figure 3

Temporary Crack Width Stabilizing Welds

6) WELDING REPAIR PROCEDURES

Selection of repair procedure depends upon the nature of discrepancy.

Procedure A

Repair of partial penetration crack in weld metal.

Procedure B

Repair of partial penetration crack in weld metal, heat affected zone * and parent metal.

Procedure C

Repair of through crack in weld metal, heat affected zone * and parent metal.

Procedure D

Repair of edge crack.

Procedure E

Partial or complete plate removal.

Procedure F

Welding and repair of appurtenances.

* Heat Affected Zone (HAZ) is defined as that portion of the base metal that has not been melted as the result of the heat introduced by welding, but which mechanical properties and microstructure have been altered by the heat of the welding.

For the purpose of this procedure, the maximum width of the Heat Affected Zone is 16 mm as measured from the toe of the weld (Figure 4).

Figure 4

Definition of Heat Affected Zone

Maximum width of the heat affected zone is 16mm as measured from the toe of the weld.

Procedure G

Repair of welded tap pads.

Procedure H

Field reinstallation of power pack guide bars.

Procedure I

Field installation of hatches.

Procedure J

Repair of punctured holes

After the appropriate Repair Procedure has been selected, no attempt shall be made to perform any weld repair if ambient temperature is less than +10 o C, unless the following preheat precaution is taken: for ambient temperature less than +10 o C, the area to be repaired shall be preheated to +75 C.

Whenever possible weld repair will be conducted inside a building. No repair will be done when the area of a vehicle to be repaired is exposed to rain, snow or high winds.

After a crack repair has been completed as per selected procedure and the quality of weld repair found acceptable as per Inspection Standards for Completed Repair Welds, Appendix A, repaired area will be spot primed and painted.

PROCEDURE A

REPAIR OF PARTIAL PENETRATION CRACK IN WELD METAL

Crack shall be properly identified and documented and this repair procedure assigned.

Crack will be removed by arc-air gouging and grinding. Excavation walls included angle shall be no less than

22 and root radius no less than 3mm.

Air hammer chipping shall be utilized if required to remove arc-air gouging residuals.

Excavation will be examined visually and by Liquid Penetrant for complete crack removal.

Excavation shall be welded by GMAW (SMAW is an allowed option) as per Chart 1 and 2.

Repair weld shall be inspected visually and by Liquid Penetrant for conformance with weld repair quality standards, Appendix A. Radiography can be used as an optional method.

Repair weld will be blended by grinding to the contour of the original weld or parent metal.

PROCEDURE B

REPAIR OF PARTIAL PENETRATION CRACK IN WELD METAL,

HEAT AFFECTED ZONE, OR PARENT METAL

Crack will be removed by arc-air gouging and grinding. Excavation walls included angle shall be no less than and the root radius no less than 3mm.

Air hammer chipping shall be utilized if required to remove arc-air gouging residuals.

Excavation will be examined visually and by Liquid Penetrant for complete crack removal.

Excavation shall be welded by GMAW (SMAW is an allowed option) as per Chart 1, 2 or 3 as applicable.

Repair weld shall be inspected visually and by Liquid Penetrant for conformance with weld repair quality

PROCEDURE C

REPAIR OF THROUGH CRACK IN WELD METAL, HEAT AFFECTED ZONE AND PARENT

METAL

Crack will be removed from one side by arc-air gouging and grinding as per sketch A, and welded as per sketch

B.

From the opposite side, crack will be removed using the same method as per sketch C and welded as per sketch

D. Air hammer chipping will be utilized, if required, to remove arc-air gouging residuals.

Excavations will be examined visually and by Liquid Penetrant for complete crack removal.

Excavations will be welded by GMAW (SMAW is an allowed option) as per Chart 1, 2 or 3 as applicable.

Repair weld shall be inspected visually and by Liquid Penetrant for conformance with weld repair quality

PROCEDURE D

REPAIR OF EDGE CRACK

For repair cracks which start or stop at the edges, follow instructions from Weld Joint Repair Procedure B or C, whichever applies.

Application of run-off block is mandatory.

After run-off tab was removed, grind edge smoothly and perform Liquid Penetrant inspection. Edge has to be free of any indication. Repair weld will be inspected visually and by Liquid Penetrant for conformance with weld repair quality standards, Appendix A. Radiography can be used as an optional method.

PROCEDURE E

PARTIAL OR COMPLETE PLATE REMOVAL

In the case of full plate removal, affected plate will be burnt out along existing welded joints, and a new plate fitted in place and welded.

In the case of a partial plate removal, the plate will be burned out along some of the existing welded joints, but also some new burning lines will be created which will subsequently be consumed into the new welding joints.

Prior to any repair work, the plate or portion of the plate that is to be replaced, will be properly identified and marked up. If a new burn out line/subsequent welding seam is to be created, it will also be marked up clearly.

Prior to any repair work, all externally and internally mounted components will be removed from the marked plate and its vicinity. This includes wiring harnesses, rubber and plastic hoses, metal tubes and pipes, straps, control boxes and any other components which could suffer any damage during subsequent weld repair.

Internally and externally mounted components which are impractical to remove, will be protected by wrapping around suitable temperature and spark resistant blankets.

Prior to any repair work all appurtenances (tapped pads, brackets, channels) which are located within marked up area of the plate, will be identified. Their relative location to some suitable selected fixed points of the weldment will be recorded. Sketch will be developed showing location of all the identified appurtenance relative to the selected fixed points. Sketch will be dimensioned by measuring distances from appurtenances which are to be removed relative to the fixed points using measuring tapes, straight edges, right angles and other suitable measuring tools. All identified appurtenances will be removed by arc-air gouging and/or grinding and saved together with sketch for reapplication or discarded if new appurtenances are to be applied.

Prior to any removal of plate, reinforcing braces will be applied to support welded structure in the area of opening which will be created after plate removal.

Application of reinforcing braces will have to be handled on a case-by-case basis as per the following general instructions:

· mild steel angular irons, C-channels or light wall round or square tubes are suitable for bracing.

· cross-section of selected brace member will be within 50-65mm (width) and wall thickness with

5-6mm.

· braces are to be measured and cut to length prior to application.

· braces are to be welded to the structure over the existing welds or within 12 mm distance measured from the toe of existing welds by placing temporary welds no more than 4mm in size and 20mm in length as per Charts 1 and 2.

· braces must not be welded to the plate or portion of the plate which is to be removed in the subsequent operation.

· when braces are applied, adequate access has to be provided to all areas requiring weld repair.

· after weld repair is completed, braces will be removed and temporary welds sanded flush to the contour of parent plate. Former location of temporary weld will be inspected by Liquid Penetrant after brace and weld removal. No indications in parent material are allowed.

Arc-air gouging, flame or plasma cutting will be used to burn out whole plate or portion of the plate. Nozzle and tip selections have to follow recommendations of a cutting equipment manufacture for the plate thickness to be cut.

Burn along existing weld joints or newly created burning/welding line, leaving 3-4 mm of material to be removed by subsequent grinding operation. Maintain steady cutting speed and use suitable accessories (guiding bars, guiding wheels and similar) to maintain steady cutting speed and to follow cutting line.

After a plate, or a portion of plate, is completely burnt out and removed, edges of the created opening will be prepared for welding of a new plate by grinding.

Material in the area of existing weld joint will be ground back to the original contour of joint.

Material in the area of newly created burning line will be ground back to previously drawn line and prepared for symmetrical double V joint with 30 bevel.

Once completely prepared, edges of the opening will be inspected by Liquid Penetrant. No indications are allowed.

Replacement plate will be manufactured from the same class and same thickness material to fit into created opening. Edges of replacement plate will be prepared to the contour of original welds, or symmetrically bevelled at 30 degree for newly created welding joint. Plate edges will be prepared by grinding. If practical, all appurtenances discarded with the removed portion of the plate can be located and welded to the replacement plate at this stage of repair. Their location will be checked as per previously developed sketches and when confirmed they will be welded per Chart 1 or 2.

Plate edges will be inspected by Liquid Penetrant prior to the application. No edge indications are allowed.

Plate will be fitted in the opening and trimmed by grinding as required to achieve original configuration for each of removed weld joints and double V joints with 60 included angle and 2-3 mm space for new created joints.

Replacement plate will be tack welded in place by exterior tack welds. Tack welds, no more than 4 mm in size and 25 mm in length, will be equally spaced at 150 mm and welded per Chart 1 or 2.

After replacement plate is securely tack welded, all joints will be inspected visually for cleanliness and fitup.

All joints will be first welded from interior as per Chart 1 or 2. The number of applied passes per joint will depend on groove preparation and welding conditions and will be sufficient to provide 1 - 2 mm bead height.

For complete penetration joints non-metallic backing or root pass welded at lower range of allowed parameters is recommended. Exterior joints will be back ground to the sound metal.

Air or electric disc grinders will be used for back gouging to create grooves with a minimum included angle of

22 and a minimum bottom radius of 3mm.

After exterior grooves are prepared and completely cleaned out, Liquid Penetrant method will be used to inspect the grooves. No indications are allowed.

All exterior welds will be welded as per Chart 1 or 2. Number of applied passes per joint will depend on groove preparation and welding conditions and will be sufficient to provide 1-2 mm bead height.

Repaired area will be completely cleaned and inspected visually and by Liquid Penetrant for conformance with weld repair quality standards, Appendix A. Radiography can be used as an optional method.

Remaining appurtenance (tapping pads, brackets, channels and similar members) which were removed with the plate and saved, will be reapplied or the new ones will be applied. They will be located manually, as per previously developed sketch, using measuring tape, straight edge, night angle and other similar tooling, and tack welded in place.

Location of each of the reapplied piece of appurtenance will be confirmed by measuring twice and then they will be welded as per Chart 1 or 2.

All appurtenance welds will be inspected visually and by Liquid Penetrant for conformance with weld repair quality standards, Appendix A.

PROCEDURE F

WELDING AND REPAIR OF APPURTENANCES

If appurtenances (pad, channel, bracket) were completely separated from the plate by excessive mechanical force, the event shall be properly identified and documented and this repair procedure assigned.

Area shall be examined visually, missing appurtenance properly identified by part number and new one drawn from stock.

Remaining weld metal shall be sanded off the plate and area examined visually and by Liquid Penetrant. No indications are allowed. If indications in the plate are revealed, by either visual or Liquid Penetrant examination, refer to chapter 4 of this repair procedure.

If appurtenance (pad, channel, bracket) were damaged beyond use but still held to a plate by original weld, the event shall be properly identified and documented and this repair procedure assigned. Appurtenance shall be removed by grinding the metal off to the surface of the plate and discarding the appurtenance. For large appurtenances, welds can be removed by arc-air gouging but only up to 3mm above plate level. Remaining weld metal shall be then ground off.

Area shall be examined for complete appurtenance removal, appurtenance properly identified by part number and new one drawn from stock. Plate shall be examined visually and by liquid penetrant. No indications shall be allowed. If indications in the plate are revealed either by visual or liquid penetrant examination, refer to

Chapter 4 of this repair procedure.

New appurtenances shall be properly located and tack welded to the plate. Location of the tack welded appurtenance shall be double checked and appurtenance welded by GMAW (SMAW is an allowed option) as per Chart 1 and 2 and information provided in this procedure.

Weld shall be inspected visually and by Liquid Penetrant for conformance with weld repair quality standard, Appendix A.

Based on the design appurtenances shall be welded as follows:

PROCEDURE G

REPAIR OF WELDED TAP PADS

This procedure allows the operator to perform optional repairs to the interior or exterior mounted pads instead of replacing the pads as described in procedure “F”.

If a tap pad was damaged beyond the use has entrapped a broken part of the bolt or the thread of the tap pad is damaged, but the pad is still attached to the armor plate by original weld the following repair procedure can be used.

All mounted hardware that can be damaged by a repair shall be either removed or protected by fireproof tarp.

The broken part shall be removed and existing thread in the tap pad shall be drilled out. Drilling should not protrude into the parent armor plate.

The hole in tap pad shall be plug welded using Solid Wire Gas Metal Arc Welding (GMAW) process, as per

Chart 1.

The excess of weld metal shall be ground off from the top of the tap pad.

Redrill and retap shall follow next to restore the original thread in repaired tap pad.

IF ANY WELDING NEEDS TO BE PERFORMED ON THE OUTSIDE OF THE HULL THE SPALL

LINER HAS TO BE REMOVED AND REPLACED.

INTERIOR MOUNTED PADS

EXTERIOR MOUNTED PADS

PROCEDURE H

FIELD REINSTALLATION OF POWER PACK GUIDE BARS

This procedure provides a guidance for reinstallation of the power pack guide bars.

If the guide bars were damaged or bent and cannot be straighten to acceptable profile but still held by original welds the following procedure shall be applied to install new guide bars.

The guide bars shall be removed by grinding off at places where they were welded to the vehicle (Strut tube and engine partition). Remaining weld metal shall be ground off and area visually examined. No indications are allowed. New guide bars shall be drawn from stock.

To install the guide bars a welding fixture for power pack guide mounts shall be used.

The fixture is to be mounted onto two left-hand engine mounts and first right hand engine mount.

The new guide bars shall be positioned into the fixture and welded to the strut tube and engine partition.

PROCEDURE I

FIELD INSTALLATION OF HATCHES

Originally installed hatches could be damaged in certain situations resulting in a requirement to install the new ones. The purpose of this procedure is to provide instructions on how to perform the reinstallation of new hatches in a field environment. It is strongly recommended that all personnel involved be trained on the mock-up and be able to demonstrate their ability to follow the instructions as outlined in this procedure.

Partial disassembly of the vehicle’s exterior equipment may be required to provide necessary access to the exterior surfaces where the hatch as use to be installed.

ENGINE

HATCH

ENGINE AIR

INTAKE

HATCH

AIR INLET

HATCH

COOLING

GRILLS

HYDRAULIC

RESERVOIR

ACCESS HATCH

POWER

ENTRY PANEL

HATCH

(SAME AS SIGNAL

ENTRY PANEL HATCH)

FRONT

HATCH

DRIVER'S

HATCH

SIDE

HATCH

SIGNAL

ENTRY PANEL

HATCH

A) Installation of the Signal Entry Panel, Power Entry Panel, Side and Front Hatches

Check the installed seal around the hatch opening. Locate the hatch in the opening maintaining a gap of

1-3mm all around. If required, the hatch plate shall be custom formed to obtain a flush condition with the hull. The edges of the hatch can be ground to obtain a gap of 1-3mm.

Close the handle leaving the gauges in place. Using the pins locate the hatch hinges. The hatch hinges shall be pushed outboard until there is no gap with the hull hinges. Tack weld the toe of the hinge to the hatch plate and drive the wedge between the hinge and the hatch to obtain flushness. Tack weld the hinge to the hatch on the side opposite to wedge. Remove the wedges and ensure proper functioning of the hatch by opening and closing it. Complete all welding as required.

B) Installation of the Engine Hatch

Locate the hatch in the hull opening and check flushness with the hull. The engine hatch may have to be custom formed to obtain a flush condition. Using a gap gauge set a gap of 1-3mm on the two sides of the hatch where the seal is applied. Use clamping fixture to ensure the flushness of the hatch with the hull, locate the hatch hinges. The hatch hinges shall be pushed outboard to eliminate any gap with the hull hinges. Tack the hinges to the engine hatch. Use a device to set the opening angle for the engine hatch at 77 . Remove the hatch. Complete all welding as required.

C) Installation of the Driver’s Hatch

Use the fixture to locate the driver’s hatch and the hinges into position. The hatch hinges shall be spaced with the 1mm gap of the hull hinges. Maintain a 1-3mm gap all around the edge of the hatch.

Tack the hinges in place. Remove the hinge bar. Lift off the hatch. First weld the bottom of both hinges then the top. Next weld outboard on the hinges. Complete all welding as required.

D) Installation of the Cooling Grills and Maintenance Hatches

Place the cooling grill cover on the hull. Push the cover all the way toward the driver’s side and back against the rear roof. The grill cover must be fitted to the hull to ensure a maximum allowable gap of 10mm. Bolt the cover to the hull. Place the Hydraulic Reservoir Access hatch and the Engine Air

Intake hatch in the openings of the grill cover. The hatches shall be centered in the openings with a maximum allowable gap of 1- 3mm all around. The hatches shall be flush with hull within +/-3mm and the total deviation shall not exceed 4mm. Using the pins locate the hinges and push them outboard. Tack the hinges to the covers. Complete welding as required per drawing.

To install the Air Inlet Grill, place the two base hinge plates over the holes in the cooling grill cover and bolt them to the cover. Locate the Air Inlet Grill in the opening and push it all the way toward the back.

Using the pins, locate the hinges and push them outboard. Complete welding as required. Manually locate strips all around the cooling grill cover and weld as required.

PROCEDURE J

REPAIR OF PUNCTURED HOLES

The punctured hole in armour plate shall be properly identified and documented.

The hole shall be opened to a minimum 15 mm in diameter by grinding from the face side (interior or exterior of the vehicle, “easy access” side). The wall of the hole shall be ground to 30 off the vertical protruding to face side.

The ground surface shall be examined by Liquid Penetrant to insure crack free edges of the joint.

Full penetration weld is required and the welding to be done from the face side using backing plate, placed on the back of the joint.

For welding use GMAW ( SMAW is an allowed option ) as per Chart 1, 2 or 3 as applicable.

The size of the backing plate shall be 6 mm (1/4”) thick and 50 mm (2”) above the edge of the ground hole (sketch below).

The backing plate must always be made of a material that is metallurgically compatible with the armour plate and the welding electrode to be used.

If backing plate does not interfere with the serviceability of the vehicle then the backing plate will be welded permanently all around to main plate.

Otherwise, it should be removed, in which case the back side of the joint must be accessible and the backing plate will be only tacked to main plate . Once welding is completed the backing plate is removed and the root weld shall be blended by grinding to the contour of the main plate.

Completed repair weld, the face and root, shall be inspected visually and by Liquid Penetrant for conformance with weld repair quality standards, Appendix A. Radiography can be used as an optional method.

30 Face Side ( “Easy Access”)

Backing plate

50 15

7) WELDING TECHNIQUES, PRACTICES AND PROCEDURES

To successfully complete repair work it is essential to follow guidelines for techniques and practices of the procedures employed.

CHART 1

WELD PARAMETERS FOR GMAW PROCESS5

Weld wire: ER70 S-6, per MIL-E-23765/13, 0.89mm diameter

Shielding gas: Mixture 75% Ar + 25% C0 , C-25

Welding current: DC, reverse polarity

Welding amperage: 120 ± 25A for vertical and overhead position2

220 ± 20A for horizontal and flat position1

Welding voltage: 20 ± 2V for vertical and overhead position

31 ± 2V for horizontal and flat position1

Shielding gas flow: 30-40 cu.ft. per hour

Interpass temp: 300 F max. when multiple pass is required to fill in excavation4.

1 Flat weld position to be used whenever possible.

2 Only vertical - up direction of travel is permissible.

3 Welding consumable certified to AWS A5.18 is an acceptable alternative 4 Warm-to-touch is an acceptable alternative for determining interpass temperature before welding

Continues 5 DVH specific requirements are provided in appendix D.

CHART 2

WELD PARAMETERS FOR SMAW (OPTIONAL)

Weld rod: E7018, AWS A-5.1*

Welding current: DC reverse polarity (AC allowed if DC power source is not available)

Welding amperage: 170-190 for flat and horizontal position, electrode dia. 4.0mm**

95-130 for vertical and overhead position, electrode dia. 3.2mm***

Welding voltage: Keep arc as short as possible

Interpass 300 F max. when multiple pass is required to fill temperature: in excavation.****

Slag cleaning: Complete slag cleaning between passes and after last pass

* Take electrodes only from recently opened sealed packages or from electrode oven if one is available. If electrode is taken from the oven, it has to be baked at 350 C for at least one hour before it can be used. If the electrode holding oven is available, take the electrodes from a freshly open package, put them in the holding oven and take them out as required. Remove from the package or from the oven only the number of electrodes which will be consumed in the next 0.5 hours. Keep the package sealed and oven closed all the time.

** Flat weld position to be used whenever possible.

*** Only vertical - up direction of travel is permissible.

**** Warm-to-touch is an acceptable alternative for determining interpass temperature before welding continues.

CHART 3

WELD PARAMETERS FOR SMAW (OPTIONAL)

FOR BASE PLATE REPAIR ONLY

Weld rod: E7018, AWS A-5.1*

Welding current: DC electrode positive (AC allowed if DC power source is not available)

Welding amperage:

Flat Position **

Vertical Position *** and Overhead Position

Armor

Thickness

(MM)

Pass

Diameter

Amperage

Amps

Pass

Diameter

Amperage

Amps

5.41 and

6.41

All 3.2 110-140 All 2.4 60-80

7.31 and

9.71

Root

Cover

2.4

3.2

80-100

120-150

All 2.4 75-85

12.71 Root

Cover

3.2

4.2

110-140

150-190

Root

Cover

2.4

2.4

80-100

70-90

Welding voltage: Keep arc as short as possible

Interpass temperature: 300 F max. when multiple pass is required to fill in excavation****

Slag cleaning: Complete slag cleaning between passes and after last pass

* Take electrodes only from recently opened sealed packages or from electrode oven if one is available. If electrode is taken from the oven, it has to be baked at 350 C for at least one hour before it can be used. If the electrode holding oven is available, take the electrodes from a freshly open package, put them in the holding oven and take them out as required. Remove from the package or from the oven only the number of electrodes which will be consumed in the next 0.5 hours. Keep the package sealed and oven closed all the time.

** Flat weld position to be used whenever possible.

*** Only vertical - up direction of travel is permissible.

**** Warm-to-touch is an acceptable alternative for determining interpass temperature before welding continues.

ARC-AIR GOUGING

When arc-air gouging is employed during repair, the following guidelines are to be followed:

· Manual arc-air gouging is considered

· Gouging electrodes shall be carbon copper coated electrodes

· Gouging electrode diameter shall be 4.8mm (in the absence of 4.8mm dia. electrode, 6.4mm dia.

electrode is permissible)

· Direct current, reverse polarity is recommended 150-250 amps for 4.8mm dia. and

200-400 amps for 6.4 dia. electrode

· Electrode holder and cables have to be properly selected for the size of electrode and current

· The electrode shall extend up to 150mm maximum from the holder and shall be increased by

15-25 from the direction of travel, see Figure 5.

Figure 5

Arc-Air Gouging Practices

· Air supply of 50 to 100 psi pressure is required to eject molten metal. In the absence of the compressed air, use of bottled inert welding shielding gas is permissible but some sacrifices in quality is possible.

· The depth and contour of groove are controlled by the electrode angle and travel speed.

A small push angle and slow travel speed will produce a narrow, deep groove. A large push angle and fast speed will produce wide shallow groove.

· The width of the groove is determined by the size of electrode and it is usually 3mm wider than the size of electrode used.

SMAW WELDING

SMAW welding is permissible as an optional welding process in this repair procedure. E7018 class coated electrode, which is low hydrogen type of electrode suitable for all position welding and containing 25-40% weight percent of iron powder in coating is recommended.

The best results will be achieved if the following guidelines are followed:

· Direct current reverse polarity is recommended although altering current is permissible.

Alternating current will impact smoothness of the arc and increase spatter.

· Direction of travel is backhand for welding in horizontal and flat position and upward for welding in vertical position. Welding in overhead position is not recommended but when necessary backhand direction of travel shall be employed.

· Arc length shall be maintained in a manner not to exceed size of the core of the electrode.

Too long arc causes excessive spatter.

· Electrode shall be positioned in general position shown in Figure 6, and this position maintained during welding.

Figure 6

SMAW Welding Technique

Arc shall be striked a few electrode diameters from the place where welding is to actually begun. The arc is then quickly moved back and welding continued in normal manner, welding over the area where arc was initially originated.

· To break the arc, forward motion shall be stopped and crater allowed to fill. Electrode shall be stopped and crater allowed to fill. Electrode shall then be gradually withdrawn to break the arc.

If welding is continued from the same location, arc shall be struck at the forward end of the crater then quickly brought to the back of the crater and slowly brought forward to continue the weld.

· In order to achieve complete fusion between parent and weld metal, maximum layer thickness in groove weld shall not exceed 6mm, including root pass and maximum size of one pass in fillet weld shall not exceed 6mm. If larger welds are required, multiple pass procedures shall be used following parameters from Chart 1.

· Weaving technique is allowed while welding groove and fillet welds in vertical position travelling upwards.

GMAW WELDING

GMAW is the principle welding process employed by this welding procedure. The semi-automatic version is employed in which continuous welding electrode (wire) is continually fed and welding torch is traveled manually. Arc burns and metal melts in the protective atmosphere of a shielding gas.

The best results will be achieved if the following guidelines are followed:

· Welding machine used has to include constant voltage power source and feeder capable of feeding the wire at the rate of 200-800 inches per minute.

· Feeding mechanism has to be in good mechanical condition, equipped with feeding rolls suitable for 0.89mm (0.035") steel wire and length of the welding torch cable set is not recommended to exceed 3.5 meters.

· Welding torch has to be kept clean and nozzle cleaned periodically from the spattered metal.

· No leakage of shielding gas or cooling water (if water cooled welding torch is provided) is permissible.

· Forward travel shall be used when weld in flat, horizontal and overhead position. Upward travel shall be used when weld in vertical position.

· Work angles shall be as shown in Figure 7.

Figure 7

GMAW Welding Technique

Travel speed shall be maintained in the manner that molten metal from the weld puddle do not run ahead of the arc.

Electrode position shall be adjusted and maintained as shown in Figure 8.

Figure 8 Tip Recess and Electrode Extension

· In order to achieve complete fusion between parent and weld metal, maximum layer thickness in groove weld shall not exceed 6mm including root pass and maximum size of one pass in fillet weld shall not exceed 6mm. If larger welds are required, multiple pass procedures shall be used, following parameters from Chart 1.

· Weaving technique is allowed while welding groove and fillet welds in vertical position travelling upwards.

· Striking the arc in GMAW should not present any difficulty. To properly finish the weld is necessary to fill the end crater to the full profile of a weld. Arc is ceased by releasing the trigger on welding torch and withdrawing the torch.

LIST OF CONSUMABLES AND EQUIPMENT

a) CONSUMABLES

· welding wire, solid, ER70S-6 for GMAW process, AWS D 5.18, 0.89mm diameter.

· shielding gas, C-25, 75% Ar + 25% C0

· gouging rod, carbon, copper coated, 4.8mm diameter.

· coated electrode, E7018, AWS D5.1, 2.4mm, 3.2mm and 4.0mm diameter (optional).

· tab, mild steel, 1/4" x 1" x 2-1/4", shorter edge beveled at 45

(optional).

· tab, mild steel, thickness x 1/4" x 2", mandatory for edge crack repair.

· x-ray films (optional).

b) EQUIPMENT AND ACCESSORIES

· welder, GMAW, 35OA/60% duty cycle minimum, complete with wire feeder and welding gun, flow meter/regulator and power and ground cables.

· welder, SMAW, 350A/60% duty cycle, complete with power and ground cables, electrode holder

(optional for SMAW process).

· torch, arc-air gouging.

· flame cutting kit (oxygen and MAPP gas cylinder, cutting torch, selection of tips and nozzles), optional to arc-air gouging.

· portable plasma burner, burning torch, selection of tips and nozzles (optional to arc-air gouging).

· oven, electrode, if available.

· grinder, disc, air or electric powered for 7 inch diameter discs.

· grinder, pencil, air or electric powered for pencil grinders with cylindrical shank.

· discs, grinding, 7 inch diameter, selection of various thickness.

· grinding burrs, pencil, with cylindrical shank.

welder's safety equipment (apron, gloves, helmet, goggles).

· welder's hammer.

· brush, wire brush.

· dye penetrant kit (cleaner, penetrant, developer).

· compressed air source, minimum pressure 80 psi.

· electric power source, 115 V/60 Hz for auxiliary tools.

· electric power source, to suit welding machine input voltage range.

· crayon, temperature sensitive, 300 F.

· chipping hammer, air powered, with scale and slag removing chisel.

· x-ray tube or isotope camera (optional).

· equipment to process radiographic films (optional).

· radiographic penetrameters (optional).

· viewer, high intensity (optional).

8) SPALL LINER FIELD REPAIR PROCEDURE

1. PURPOSE AND SCOPE

Some vehicles may be equipped with internally applied spall liner panels to enhance level of vehicle occupant protection. Spall liner panels are E-glass composite held to the hull steel plates by means of a unique two part adhesive. Edges of panels are sealed to prevent penetration of moisture and NBC contamination. Exposed panel surfaces are painted with interior top coat.

Spall liner system is an inseparable part of the hull structure and does not require any regular maintenance.

However, over the course of time, exposed surfaces of spall liner panels may receive damage mostly in the form of surface marks. Certain combat situations may also cause damage to the panels. Depending upon the nature and intensity of surface marks, repair of spall liner may be required.

Requirement to perform hull structure weld repair may necessitate removal and replacement of spall liner panels in the hull affected area to allow proper access for the weld repair and to replace panels following the weld repair.

The purpose of this procedure is to identify cases when repair of spall liner panels will be required and to provide instructions on how to perform repair in the field environment.

2. PERSONNEL REQUIREMENT

There is no specific requirement for the certification of personnel involved in spall liner repair defined in this document. It is strongly recommended that all personnel involved be trained on mock-up pieces and demonstrate their ability to follow the instructions as outlined in this procedure. Basic industrial safety training is also recommended since procedure requires handling of chemicals.The adhesive is isocyanate based and personnel directly involved in repair shall wear chemically impervious gloves, breathing air personnel protective equipment and be on the Isocyanate Control Program. When cutting spall liner material safety gloves need to be worn to avoid contact with fibers.

3. DISPOSITION OF EXCESS MATERIALS

Excess materials must be disposed of in proper approved containers properly identified for the disposal of paint wastes.

4. EQUIPMENT CONDITIONS

Prior to start of any spall liner repair, the vehicle shall be parked in large and well ventilated indoor area preferably inside an ventilated booth. If weather permits, repair shall be performed outdoors for best ventilation conditions. Parking brake shall be applied, transmission shifted to “N” and the engine turned off.

Environmental temperature at the location of repair shall be between 15 and 30 degrees centigrade.

Partial disassembly of vehicle interior equipment may be required to provide required access to the interior surfaces where spall liner repair is required. All disassembled components shall be safely stored for re-application following spall liner repair.

5. REPAIR IDENTIFICATION

The guidance given herein is to be used in conjunction with appendix C (Stryker BCT Spall Liner

Acceptance Criteria)

Interior spall liner panels should be inspected from time to time for their conditions.

Spall may be inspected visually and by physical contact. Light probing of spall panels using tools, including but not limited to flat head screwdrivers, is an acceptable method of inspection.

Repair will not be required if inspection reveals one or more of the following conditions:

shallow surface scratches and gauges shallow surface chips and dents impressions and indentations through hole of less than 6 mm in diameter provided hull steel armor is intact former location of self-tapping screws resulting from relocation of interior vehicle equipment

Repair will be required if inspection reveals one or more of the following conditions:

any delamination and clear separation of panels’ fibers resulting from the act of any kind of physical force or as the result of hull weld repair performed in the vicinity of applied spall liner panel through hole of more than 6 mm in diameter distortion and bulges of panels resulted from exterior penetration of an object through armor steel shell major hull structural repair involving complete or partial replacement of hull plates covered with spall liner panels. Following completion of hull repair affected spall liner panels will have to be re-applied.

separation, deterioration or complete absence of edge caulking material removal and subsequent replacement of spall liner panels may be required in preparation for and following the completion of hull weld repair even if spall liner panels in question do not require repair on the merit of their own damage

6. REQUIRED TOOLS AND MATERIAL

To successfully perform spall liner repair as outlined in this procedure, the following tools and materials are required at a repair site:

Tools:

utility knife steel straight edge 300 mm (12 inches) length measuring tape, 3 meters (10 feet) marker, pencil etc.

75 mm dia (3 inches) hole saw with appropriate powered drill, electric or air powered selection of scrapers/spatulas, 25, 50 and 75 mm wide (1, 2 and 3 inches) wide selection of paint brushes 25, 50 and 75 mm wide (1, 2 and 3 inches) sand paper 80-120 grit size air chisel or as an alternative hand chisel and hammer or hydraulic scissors wedge device solvent, ex. Isopropyl Alcohol, Ethyl Lactate or Solution EP 921 (see appendix 3) electrically powered jig saw or as an alternative hand held cross saw caulking gun work bench or other suitable hard working surface clamping tools cleaning rags wooden blocks 50x50 mm square, 250 and 500 mm length (2x2x10 and 2x2x20 inches)

M8 bolts, hexagonal heads, 70 mm length

C-clamps, Bessemer, various sizes

Material

Spall liner panel, this is full size 2.4 x 1.2 meters (8x4 feet) sheet from which required pieces may be custom cut

Adhesive includes clear base and activator. When mixed in proper ratio they produce adhesive

Standard 75 mm Dia spall liner repair plug

Paint primer

Interior paint top coat

Exterior top coat

Vinyl wash primer ( DO NOT use on BCT and USMC contracts )

Vinyl wash activator ( DO NOT use on BCT and USMC contracts )

Vinyl wash reducer ( DO NOT use on BCT and USMC contracts )

Caulking compound

7. REMOVAL OF DAMAGED SPALL LINER AND SURFACE PREPARATION FOR ACCEPTANCE

OF REPAIR PIECE

After damage to spall liner was identified and need for repair established or when the need for removal of spall liner has been identified to allow for subsequent hull weld repair, affected spall liner shall be removed as follows:

Removal of localized damage:

Localized damages will be removed by using 75 mm dia hole saw placing the damage as close as possible to the center of rotation of the saw. A 75 mm dia cut shall be made in spall liner. Cut shall be made through entire thickness of the spall liner taking care that no damage is done to the hull steel shell. Using air or hand chisel, damaged piece shall be removed without damaging surrounding spall liner material. The old adhesive shall be removed by scraping and sanding until smooth surface is obtained. The area must be mechanically cleaned from all solid particles and chemical cleaning performed using solvent such as isopropyl alcohol or solution EP 921 to obtain clean steel surface ready to accept replacement piece.

Removal of extensive damage

An extensively damaged spall liner panel may have to be removed partially or completely. For partial removal damaged area shall be identified and marked. The section to be removed is preferably rectangular for ease of cutting. using straight edge and marker/pencil, lines shall be drawn and area to be removed clearly marked. Using straight edge and utility knife a cut needs to be made along marked line through entire thickness of the affected liner. Using air or hand chisel, damaged piece shall be removed not damaging surrounding spall liner material. The old adhesive shall be removed by scraping and sanding until smooth surface is obtained. The area must be mechanically cleaned from all solid particles and chemical cleaning performed using solvent such as isopropyl alcohol or solution EP 921 to obtain clean steel surface ready to accept replacement piece.

For the removal of entire panel, the affected panel needs to be properly marked. Using air or hand chisel, damaged panel shall be removed not damaging surrounding spall liner material. Heat may be used to soften the adhesive providing steel plate temperature underneath spall liner does not exceed 150 degrees centigrade.

The old adhesive shall be removed by scraping and sanding until a smooth surface is obtained. The area must be mechanically cleaned from all solid particles and chemical cleaning performed using isopropyl alcohol or solution EP 921 to obtain clean steel surface ready to accept replacement piece.

8. PREPARATION OF HULL SURFACE TO ACCEPT REPLACEMENT SPALL LINER

The area of hull steel shell where damaged spall liner has been removed and new spall liner is to be applied, shall be free from mechanical dirt and rust prior to application of replacement spall liner piece. If the interior surface paint on steel hull has not been damaged following the damaged spall liner removal, no further treatment is required. If the interior paint has been removed from the steel hull and replacement spall liner will be applied within 8 hours following the removal of damaged spall liner, no further treatment of steel surface will be required since no significant rust will develop. If replacement spall liner will be applied beyond 8 hours period, exposed steel surface shall be wiped with isopropyl alcohol and primed with primer

(Refer to appendix I for mixing instructions).

9. PREPARATION OF REPLACEMENT SPALL LINER

Replacement spall liner may be ready 75 mm plug or custom replacement piece cut out of row panel. If custom piece needs to be cut, panel shall be placed on work bench or other suitable hard surface of adequate size and at proper working height.

Replacement piece shall be laid out so that its size and shape match damaged piece previously removed.

Cutting of replacement piece may be performed using electrically powered jig saw or hand held cross saw.

Care needs to be taken not to damage protective cover while handling and cutting spall liner material.

10. MIXING OF ADHESIVE

Adhesive shall be mixed from the clear base and white activator in the ratio of 100 parts of clear base and 66 parts of activator. A quantity of base and activator required to perform repair shall be poured in clean container and hand stirred for 2 - 5 minutes. Once mixed, the adhesive must be used within 30 - 60 minutes.

11. REPAIR PROCEDURES

Following the visual examination of spall liner panels, it may be determined that some are damaged to the level which requires repairs. Depending upon nature and intensity of damage, one or more of the following repair procedures may be assigned:

Repair of small localized surface holes

When presence of localized surface holes less than 6 mm in dia was determined, this shall be adequately documented. As the minimum, documentation shall include vehicle serial number, location and number of detected holes. The hole may be left from self tapped screws following the relocation of vehicle of interior equipment or results of an act of localized mechanical force.

This repair procedure shall be assigned.

Localized surface holes will be filled by caulking compound and surface smoothened. After caulking has cured enough, approx. 1 hour, the repaired area will be primed and painted using paint primer and paint top coat (Refer to appendix I for mixing instructions).

Repair will be inspected documented.

Repair of localized surface marks using standard 75 mm plug

When presence of localized surface marks was determined, this shall be adequately documented. As the minimum, documentation shall include vehicle serial number, location and number of detected…