TASK 72-50-21-300-036 LPT Case - Weld Repair Of Cracks Adjacent To The Borescope Hole, Repair-036 (VRS4474)

DMC:V2500-A0-72-50-2101-03A-627A-C|Issue No:003.00|Issue Date:2015-08-01

Export Control

EAR Export Classification: Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3), except for the following Service Bulletins which are currently published as EAR Export Classification 9E991: SBE70-0992, SBE72-0483, SBE72-0580, SBE72-0588, SBE72-0640, SBE73-0209, SBE80-0024 and SBE80-0025.

Copyright

© IAE International Aero Engines AG (2001, 2014 - 2021) The information contained in this document is the property of © IAE International Aero Engines AG and may not be copied or used for any purpose other than that for which it is supplied without the express written authority of © IAE International Aero Engines AG. (This does not preclude use by engine and aircraft operators for normal instructional, maintenance or overhaul purposes.).

Applicability

All

Common Information

TASK 72-50-21-300-036 LPT Case - Weld Repair Of Cracks Adjacent To The Borescope Hole, Repair-036 (VRS4474)

Effectivity

FIG/ITEM

PART NO.

01-010

3A2183

01-010

3A2265

01-010

3A2447

01-010

3A2533

Material of component

PART IDENT

SYMBOL

MATERIAL

LP turbine case

Inconel 718

General

Price and availability - none

The practices and processes referred to in the procedure by the TASK number are in the SPM.

Before start of repair, remove borescope boss, refer to Repair VRS4341, TASK 72-50-21-300-030 (REPAIR-030). If in good condition, retain boss for later use. After completion of repair, install boss again, refer to Repair VRS4341, TASK 72-50-21-300-030 (REPAIR-030).

If oven stress relieving method is used, remove screw inserts, refer to Repair VRS4049 TASK 72-50-21-300-026 (REPAIR-026). After repair replace screw inserts, refer to Repair VRS4049 TASK 72-50-21-300-026 (REPAIR-026).

In Step, all equipment and material required for local stress relieving method will be of local purchase with the exception of coil. Trials should be carried out on discard components to make sure the success of local stress relieving before trying to repair on case.

NOTE

For equipment and materials necessary to do this repair refer to SPM TASKS below:
TASK 70-11-03-300-503
TASK 70-23-05-230-501
TASK 70-31-13-310-501
TASK 70-37-00-370-501
TASK 70-37-01-370-501
Equivalent equipment may be used.

NOTE

To identify the consumable materials, refer to the PCI.

NOTE

Special tools are identified in the procedure by the tool primary number.

Preliminary Requirements

Pre-Conditions

NONE

Support Equipment

NameManufacturerPart Number / IdentificationQuantityRemark
FileLOCALFile
Various stonesLOCALVarious stones
Hand held grinderLOCALHand held grinder
Welding equipmentLOCALWelding equipment
OvenLOCALOven
ThermocoupleLOCALThermocouple
Standard induction heaterLOCALStandard induction heater

Consumables, Materials and Expendables

NameManufacturerPart Number / IdentificationQuantityRemark
CoMat 03-284 WELDING FILLER WIRE, NiBASELOCALCoMat 03-284

Spares

NONE

Safety Requirements

NONE

Procedure

    1. SUBTASK 72-50-21-230-105 Determine Location and Length of Cracks

      1. Do the test for cracks locally.

      1. Refer to the SPM TASK 70-23-05-230-501.

        Use medium sensitivity level.

        Repair cracks which begin only from borescope hole or rivet holes and are not more than 0.700in. (17.8 mm) in length.

    2. SUBTASK 72-50-21-350-095 Prepare Surfaces before Welding

      1. Completely V-groove full length of crack.

      1. Use hand held grinder. If cracks go through from outer surface, V-groove to half depth and weld up. After this, V-groove from other surface until weld seam as necessary. Weld up other side as usual. Keep material removal to a minimum to remove cracks.

    3. SUBTASK 72-50-21-110-102 Clean the LP Turbine Case

      1. Clean the part.

      1. Refer to the SPM TASK 70-11-03-300-503.

    4. SUBTASK 72-50-21-310-055 Weld up Prepared Surfaces

      1. Weld up prepared areas. Use manual tungsten inert gas technique.

      1. Refer to Figure, Figure and Fig. 72-50-990-042-003 and the SPM TASK 70-31-13-310-501.

        Refer to Step for welding up of through-cracks.

    5. SUBTASK 72-50-21-370-058 Heattreat Component in an Oven after Welding

      NOTE

      This process is an altrnative to local stress relief method in Step.

      1. Heattreat component.

    6. SUBTASK 72-50-21-370-059 Heattreat Component using Local Stress Relief Method after Welding

      NOTE

      1. This process is an alternative to oven stress relief method in SUBTASK 72-50-21-370-058.

      2. Use one of the methods given in step C, step D and step E. It is necessary for this method that the stress relief temperature is carefully monitored and kept within given limits. Therefore, thermocouples must be attached to the weld area repaired and coupled to accurate readout equipment. Chromel/Alumel (Ni-Cr-Ni) thermocouple wire is recommended for this repair.

      1. Heattreat component.

      1. Refer to the SPM TASK 70-37-01-370-501 without item (a) for heat treatment cycle or heat to 1335 to 1365 deg F (724 to 740 deg C) with a heating rate not faster than 54 deg F (30 deg C) per min. and hold for 4 hours. For cool down refer to cycle in the SPM TASK 70-37-01-370-501.

      2. Attach termocouple.

      1. The thermocouples must be attached to the same side of the case that the source heat is supplied from. Deterioration of thermocouples can occur. Use standard capacitance discharge weld equipment to tack weld thermocouple wire to weld bead. Do not use too much power, which causes pits in the repair area. Outer thermocouples must always be attached at the limits of the heat affected zone. Attach thermocouples as shown in Figure.

      3. Use resistance heated blanket method.

      1. To give an equal temperature distribution, the blanket must be installed tight and flat to the case surface. Use kaopak, or equivalent insulating blanket on the resistance blanket and also on adjacent areas (if weld repairing the inside surface, insulate local outer case surfaces also) to keep heat loss to a minimum.

      4. Use quartz infrared radiant heat light method.

      1. Do not locally overheat the component.

      5. Use induction coil method.

      1. Connect coil to standard induction heater. The placement height of the coil above the part surface affects the strength of the magnetic field inducted in the case and consequently the heat generated in the case. A test is required to achieve the correct height of the coil such that the heat is sufficient to stress relieve the area. On no account must the coil be set closer than 0.125in. (3.18 mm) to the case surface.

      6. Remove thermocouples.

      1. Remove thermocouples by light blending.

        Remove sharp edges from any pits caused by thermocouple installation.

    7. SUBTASK 72-50-21-230-106 Examine Repaired Areas after Heattreatment for Cracks

      1. Do the test for cracks.

      1. Refer to the SPM TASK 70-23-05-230-501.

        Use medium sensitivity level.

        No cracks are permitted.

    8. SUBTASK 72-50-21-110-103 Clean the LP Turbine Case

      1. Clean the part.

      1. Refer to the SPM TASK 70-11-03-300-503.

    9. SUBTASK 72-50-21-350-096 Blend Welded Areas to Initial Case Contours

      1. Blend inner and outer case surfaces to initial contours.

      1. Use hand held files or stones.

    10. SUBTASK 72-50-21-320-066 Restore Borescope Hole and/or Rivet Hole Diameters

      1. Machine borescope hole and/or affected rivet holes.

      1. For actual dimensions refer to Figure, Figure and Figure.

    11. SUBTASK 72-50-21-230-107 Examine Machined Borescope Hole for Cracks

      1. Do the test for cracks.

      1. Refer to the SPM TASK 70-23-05-230-501.

        Use medium sensitivity level.

        No cracks are permitted.

    12. SUBTASK 72-50-21-110-104 Clean the LP Turbine Case

      1. Clean the part.

      1. Refer to the SPM TASK 70-11-03-300-503.

    13. SUBTASK 72-50-21-220-166 Do the Post Repair Inspection

      1. Dimensionally examine the machined areas.

      1. For actual dimensions refer to Figure, Figure and Figure.

    14. Figure: Weld repair of cracks adjacent to borescope hole

    Weld repair of cracks adjacent to borescope hole

    Figure: Weld repair of cracks adjacent to borescope hole

    Weld repair of cracks adjacent to borescope hole

    Figure: Weld repair of cracks adjacent to borescope hole

    Weld repair of cracks adjacent to borescope hole

    Figure: Typical layout of thermocouples for local heat treatment method

    Typical layout of thermocouples for local heat treatment method

Requirements After Job Completion

Follow-On Conditions

NONE
Change Type:

Revised note to remove "materials or". (PSAF 15VC314)

Manufacturer Code:LOCAL
Enterprise Name:LOCALLY SUPPLIED
Manufacturer Code:LOCAL
Supply Number:CoMat 03-284
Type:sp01
Supply Short Name:CoMat 03-284 WELDING FILLER WIRE, Ni BASE
Supply Name:CoMat 03-284 WELDING FILLER WIRE, NiBASE
Specification Groups:
Doc NumberType
INCONEL 718 AMS 5832 AWS 5.14 MSRR9500/220
INCONEL 718 AMS 5832 AWS 5.14CLASS ER NI FE Cr-2 OMAT:3/206
INCONEL 718 AMS 5832 AWS 5.14CLASS ER NI FE Cr-2
Suppliers:
ManufacturerRemarks
LOCAL
28553
IE137
08489
IE508
0ZDB5
2R602
55596
58401
80357
K6835
Manufacturer Code:LOCAL
Tool Number:File
Tool Name:File
Manufacturer Code:LOCAL
Tool Number:Hand held grinder
Tool Name:Hand held grinder
Manufacturer Code:LOCAL
Tool Number:Oven
Tool Name:Oven
Manufacturer Code:LOCAL
Tool Number:Standard induction heater
Tool Name:Standard induction heater
Manufacturer Code:LOCAL
Tool Number:Thermocouple
Tool Name:Thermocouple
Manufacturer Code:LOCAL
Tool Number:Various stones
Tool Name:Various stones
Manufacturer Code:LOCAL
Tool Number:Welding equipment
Tool Name:Welding equipment