TASK 70-31-02-310-501-008 Argonarc Welding Repairs - The Procedure To Weld Corrosion And Creep Resistant Steels

DMC:V2500-00-70-31-02-07A-627A-D|Issue No:001.00|Issue Date:2013-03-20

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 70-31-02-310-501-008 Argonarc Welding Repairs - The Procedure To Weld Corrosion And Creep Resistant Steels

General

The 12 percent chromium low carbon steels specified in SPM TASK 70-31-02-310-501-002 have high strength and good creep and corrosion resistant properties. Surface scaling occurs in air if the temperature is more than 1112 deg F (600 deg C).

These steels are easily welded. Although they have high strength and brittle weld and heat affected zone, weld cracks are not a problem.

Refer to the SPM TASK 70-31-02-310-501-001 for other related TASKS.

Preliminary Requirements

Pre-Conditions

NONE

Support Equipment

NONE

Consumables, Materials and Expendables

NONE

Spares

NONE

Safety Requirements

WARNING

IT IS THE RESPONSIBILITY OF THE OPERATOR TO OBTAIN AND OBSERVE THE MANUFACTURER'S MATERIAL SAFETY DATA SHEETS FOR CONSUMABLE MATERIALS. THESE CONTAIN INFORMATION SUCH AS, HAZARDOUS INGREDIENTS, PHYSICAL/CHEMICAL CHARACTERISTICS, FIRE, EXPLOSION, REACTIVITY, HEALTH HAZARD DATA, PRECAUTIONS FOR SAFE HANDLING, USE AND CONTROL MEASURES AND ALSO TO TAKE LOCAL REGULATIONS INTO CONSIDERATION.

Procedure

    1. SUBTASK 70-31-02-310-016 Preparation of the Surface

    1. It is important that the surfaces to be welded are clean and have no scale. Surfaces can be cleaned with abrasive blasting followed with scurf mopping. Grease, abrasive particles and unwanted material must be removed with a liquid degreaser before you weld.

    2. As the inner surfaces of cracks can be oxidized, the complete length of the crack must be cut out in a V shape with a rotary cutter. This will make sure all the oxidized material is removed.

    2. SUBTASK 70-31-02-310-017 The Procedure to Weld Corrosion and Creep Resistant Steels

    1. Sufficient argon converage and backing is necessary to give a good weld.

    2. Equipment with a D.C. output must be used as specified in SPM TASK 70-31-02-310-501-001.

    3. It is not usually necessary to pre-heat repair welds in these alloys. Pre-heating could be necessary for some welds that are highly restrained or are in heavy sections. A pre-heat temperature of 842 deg F (450 deg C) can be used. Pre-heat instructions will be given in the applicable Repair.

    4. There are no special problems when you weld these steels, but a decrease in the travel speed prevents cracks on highly restrained welds.

    5. Control the current reduction at the end of the weld to prevent crater cracks.

    3. SUBTASK 70-31-02-370-006 The Heat Treatment of Corrosion and Creep Resistant steels

    1. Because of the brittleness of the weld and heat affected zone, post weld temper and stress relief is necessary. The recommended post weld heat treatment is given in SPM TASK 70-31-02-310-501-004 and SPM TASK 70-31-02-310-501-001. Heat treatment instructions are given in the applicable Repair.

    2. The high tempering temperature, gives maximum ductility in the weld and heat affected zone and should normally be used. For welds in low stressed areas, where heat treatment causes distortion problems, the lower temperature can be used.

    3. The weld must not be deformed or mechanically changed in the post welded condition, as cracks can result.

    4. If argon with five percent hydrogen is used, post weld tempering must be done in less than three days.

Requirements After Job Completion

Follow-On Conditions

NONE