DOC AIRBUS | AMM A320FTitanium Damage
TASK 51-78-00-615-804-A
Titanium Damage
The aim of this procedure is to do cleaning of titanium that has been contaminated with undecomposed or thermally decomposed fire-resistant hydraulic fluid.
Fire-resistant hydraulic fluid decomposes into a black viscous, acidic fluid or solid, beginning at 149 deg.C (300 deg.F). At 260 deg.C (500 deg.F), the decomposition rate is very rapid and the acidic decomposition product reacts rapidly with titanium. The result of this reaction is pitting, etching, hydrogen embrittlement and possible cracking. Titanium structure damaged in this way is subject to brittle failure.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
3. Job Set-up
Subtask 51-78-00-941-065-A
Subtask 51-78-00-210-052-A
[Rev.10 from 2021]
2026.04.01 01:35:08 UTC
Titanium Damage
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
CAUTION:
WHEN YOU PROCESS TITANIUM PARTS, DO NOT USE TOOL FIXTURE DETAILS MADE OF OR COATED WITH CADMIUM, BISMUTH, TIN, ZINC, GOLD OR SILVER. IF YOU DO, THESE MATERIALS CAN HAVE AN UNWANTED EFFECT ON THE TITANIUM PARTS.
CAUTION:
CADMIUM WHICH STRESSED TITANIUM CAN CAUSE CRACK DEFECTS IN THE TITANIUM AT A TEMPERATURE WHICH IS BELOW THE MELT POINT OF CADMIUM, 609 DEG F (321 DEG C).
1. Reason for the JobThe aim of this procedure is to do cleaning of titanium that has been contaminated with undecomposed or thermally decomposed fire-resistant hydraulic fluid.
Fire-resistant hydraulic fluid decomposes into a black viscous, acidic fluid or solid, beginning at 149 deg.C (300 deg.F). At 260 deg.C (500 deg.F), the decomposition rate is very rapid and the acidic decomposition product reacts rapidly with titanium. The result of this reaction is pitting, etching, hydrogen embrittlement and possible cracking. Titanium structure damaged in this way is subject to brittle failure.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | BLASTING EQUIPMENT - ABRASIVE |
| No specific | 1 | PAD - NYLON ABRASIVE |
| No specific | 1 | SCRAPER - PLASTIC |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.08BBB1) | Non Aqueous Cleaner-- Petroleum Based - |
Subtask 51-78-00-941-065-A
A. Get Access
4. ProcedureNOTE: There is no special job set-up for this task.
Subtask 51-78-00-210-052-A
A. Check of Titanium
(1) Titanium parts exposed to thermally decomposed fire-resistant hydraulic fluid do not require special treatment or checks after cleaning. However, where primer or paint has been removed by hydraulic fluid, bare metal surfaces should be carefully checked for etching, mottling, cracking or pitting. This type of attack occurs as a result of exposure to thermally decomposed hydraulic fluid.
(2) Titanium parts that show chemical attack require careful evaluation to determine their structural integrity. All incidents of chemical attack of titanium by decompsed hydraulic fluid should be reported in detail to AIRBUS INDUSTRIE.
Subtask 51-78-00-615-052-A (1) Titanium parts exposed to thermally decomposed fire-resistant hydraulic fluid do not require special treatment or checks after cleaning. However, where primer or paint has been removed by hydraulic fluid, bare metal surfaces should be carefully checked for etching, mottling, cracking or pitting. This type of attack occurs as a result of exposure to thermally decomposed hydraulic fluid.
(2) Titanium parts that show chemical attack require careful evaluation to determine their structural integrity. All incidents of chemical attack of titanium by decompsed hydraulic fluid should be reported in detail to AIRBUS INDUSTRIE.
B. Cleaning/Painting of Titanium
(a) Titanium contaminated with hydraulic fluid can be cleaned by either of following methods:
1 Remove hydraulic fluid from titanium using clean dry cheesecloth. Then wipe the area with cheesecloth dampened with cleaning agent Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) .
2 Remove hydraulic fluid from titanium using clean dry cheesecloth, then wipe area with cheesecloth dampened with alkaline cleaner. Finish wipe with water dampened cheesecloth to remove cleaner residue.
(2) Cleaning of thermally decomposed hydraulic fluid from titanium.
(a) Remove decomposed hydraulic fluid from titanium, depending on degree of decomposition, by following methods used independently or in combination:
1 Wipe with cleaning agent Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) .
2 Clean with alkaline.
3 Clean with PAD - NYLON ABRASIVE.
4 Clean with SCRAPER - PLASTIC.
5 Clean with BLASTING EQUIPMENT - ABRASIVE, 150 mesh or finer aluminum oxide.
(3) Titanium parts that have a dull or mottled appearance with no visible etching, pits or cracks, do not require immediate removal or repair. However, depending on titanium alloy and exposure conditions, such parts may have suffered a reduction in mechanical properties. An engineering review of such parts is recommended.
Subtask 51-78-00-350-054-A CAUTION:
DO NOT USE CHLORINATED SOLVENTS ON TITANIUM PARTS.
(1) Cleaning of undecomposed hydraulic fluid from titanium. (a) Titanium contaminated with hydraulic fluid can be cleaned by either of following methods:
1 Remove hydraulic fluid from titanium using clean dry cheesecloth. Then wipe the area with cheesecloth dampened with cleaning agent Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) .
2 Remove hydraulic fluid from titanium using clean dry cheesecloth, then wipe area with cheesecloth dampened with alkaline cleaner. Finish wipe with water dampened cheesecloth to remove cleaner residue.
(2) Cleaning of thermally decomposed hydraulic fluid from titanium.
(a) Remove decomposed hydraulic fluid from titanium, depending on degree of decomposition, by following methods used independently or in combination:
1 Wipe with cleaning agent Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) .
2 Clean with alkaline.
3 Clean with PAD - NYLON ABRASIVE.
4 Clean with SCRAPER - PLASTIC.
5 Clean with BLASTING EQUIPMENT - ABRASIVE, 150 mesh or finer aluminum oxide.
(3) Titanium parts that have a dull or mottled appearance with no visible etching, pits or cracks, do not require immediate removal or repair. However, depending on titanium alloy and exposure conditions, such parts may have suffered a reduction in mechanical properties. An engineering review of such parts is recommended.
C. Approved Titanium Repairs
(1) Titanium parts that are etched, pitted or cracked are considered to be permanently embrittled and should be replaced or repaired. Such repairs should be in accordance with engineering instructions.
(2) Repair of embrittled titanium parts by mechanical rework of damaged surfaces is not effective since embrittlement of the entire thickness of parts is probable.
(3) At present, degree of titanium embrittlement can only be accomplished by laboratory analysis of metal removed from suspect areas by means of spotfacing or fastener hole enlargement under engineering directions. This procedure provides a means of evaluating severity of an apparently slight attack.
(1) Titanium parts that are etched, pitted or cracked are considered to be permanently embrittled and should be replaced or repaired. Such repairs should be in accordance with engineering instructions.
(2) Repair of embrittled titanium parts by mechanical rework of damaged surfaces is not effective since embrittlement of the entire thickness of parts is probable.
(3) At present, degree of titanium embrittlement can only be accomplished by laboratory analysis of metal removed from suspect areas by means of spotfacing or fastener hole enlargement under engineering directions. This procedure provides a means of evaluating severity of an apparently slight attack.