Preliminary Requirements

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 AND USE, AND CONTROL MEASURES, AND ALSO TO TAKE LOCAL REGULATIONS INTO CONSIDERATION.

WARNING

THIS PROCEDURE INCLUDES THE USE OF SODIUM HYDROXIDE, SODIUM CYANIDE, OR POTASSIUM CYANIDE. CYANIDE SALTS AND/OR SOLUTIONS ARE VERY POISONOUS AND WORK VERY QUICKLY.

WARNING

OPERATORS MUST ALWAYS USE THE APPROVED PROTECTIVE CLOTHING SUPPLIED.

ALWAYS KEEP FINGERNAILS CUT SHORT. BE SURE FINGERNAILS ARE ALWAYS FULLY CLEAN BEFORE YOU EAT, DRINK, OR SMOKE.

DO NOT KEEP ITEMS THAT ARE USED TO EAT OR DRINK WITH IN THE SAME LOCATION WITH CYANIDE. ALSO, YOU MUST NOT EAT, DRINK, OR SMOKE AT SUCH LOCATIONS.

ALWAYS KEEP CYANIDE IN A SAFE LOCATION, WHERE ACCESS IS ONLY AVAILABLE TO APPROVED PERSONS.

A SUPPLY OF CYANIDE ANTIDOTE MUST ALWAYS BE EASILY AVAILABLE.

ALWAYS KEEP CYANIDE SALTS AND SOLUTIONS AWAY FROM ACIDS BECAUSE THE CYANIDE AND ACIDS WILL REACT TO PRODUCE HYDROGEN CYANIDE GAS.

ALWAYS OBEY THE INSTRUCTIONS OF QUALIFIED SAFETY PERSONNEL.

WARNING

SODIUM HYDROXIDE SOLUTIONS CAN BURN. ALWAYS KEEP THESE SOLUTIONS AWAY FROM YOUR EYES AND SKIN. YOU MUST USE THE PROTECTIVE CLOTHING SUPPLIED, TOGETHER WITH RUBBER GLOVES AND EYE PROTECTION.

WARNING

IF SODIUM HYDROXIDE SOLUTION GETS INTO THE EYES, FULLY FLUSH THEM WITH CLEAN WATER; THEN GET MEDICAL TREATMENT IMMEDIATELY.

WARNING

A SUPPLY OF BUFFERED PHOSPHATE SOLUTION MUST ALWAYS BE EASILY AVAILABLE, TO APPLY TO BURNS.

WARNING

BE CAREFUL WHEN YOU ADD COMPOUNDS, WHICH CONTAIN SOLID SODIUM HYDROXIDE, TO WATER, BECAUSE HEAT IS GIVEN OFF WHEN THE COMPOUND DISSOLVES. MAKE MUCH MOVEMENT OF THE SOLUTION, WITH AIR OR MECHANICAL METHODS, AS YOU ADD THE COMPOUND TO THE SURFACE OF THE SOLUTION. DO NOT ADD LARGE QUANTITIES OF THE COMPOUND TO ONE SMALL AREA OF THE TANK BECAUSE THE SOLUTION WILL BOIL.

WARNING

ALWAYS OBEY THE INSTRUCTIONS OF QUALIFIED SAFETY PERSONNEL.

CAUTION

BEFORE AND AFTER THIS PROCEDURE IS USED ON HIGH STRENGTH STEELS A STRESS RELIEF OR DE-EMBRITTLEMENT HEAT TREATMENT IS REQUIRED. (HIGH STRENGTH STEELS ARE THOSE WITH A TENSILE STRENGTH OF MORE THAN 65 TON F/IN.2 (1000 MN/M2) OR A HARDNESS OF 302 HB OR 310 HV). IF YOU DO NOT HEAT TREAT THE COMPONENTS THEY MAY CRACK DUE TO HYDROGEN EMBRITTLEMENT.

WHEN HEAT TREATMENT IS NECESSARY FOR A PART, IT IS USUALLY SPECIFIED IN THE ENGINE MANUAL OR THE OVERHAUL PROCESS.

THE SUSPENDER MUST ALWAYS BE CORRECTLY INSTALLED ON THE COMPONENT, SO THAT TOO MUCH LOAD IS NOT APPLIED TO THE THIN OR EASILY DAMAGED PARTS. TYPICAL PARTS INCLUDE COMPRESSOR DISK DIAPHRAGMS OR OTHER THIN PARTS, WHICH CAN BEND AND CRACK DURING THIS PROCEDURE.

Procedure

1. SUBTASK 70-33-86-300-001 Clean by Electrolysis

   1. Always obey the instructions given in the Safety Precautions.

   2. If necessary, stress-relieve the steel parts as follows unless specified differently in the Engine Manual.

      1. Stress-relieve.

         When this procedure is specified for Group A parts (for example, Compressor and Turbine disks), a stress-relief temperature of 554 to 590 deg F deg F (290 to 310 deg C) must be applied for two hours minimum.

         For Non-Group A parts, a stress-relief temperature of 374 to 410 deg F (190 to 210 deg C) must be applied for two hours minimum.

         NOTE

         Small parts must be put into a mild steel basket or tray with holes so that there is only one layer.

   3. Hang the parts in the solution (refer to the SPM TASK 70-33-86-100-501).

      1. For Solutions A, B, and D, the solution temperature must be 59 to 77 deg F (15 to 25 deg C). For Solution Code 58, the temperature must be as given in the manufacturer's instructions. Typically, the range is 110 to 130 deg F (43 to 54 deg C).

         NOTE

         The procedure must always end with the part as the anode, to make sure that metals contained in the solution are not held on the surface of the part.

   4. For Solutions A, B, and D, apply an electrical potential of six to eight volts. Change the polarity in cycles of 20 to 30 seconds for cathodic and 10 to 15 seconds for anodic, for the time specified in the Engine Manual. For Solution Code 58, apply the voltage/current specified in the manufacturer's instructions. Typically, a current of 25 to 35 amps is used, which alternates between 10 cycles anodic and 10 cycles cathodic.

   5. Remove the parts from the solution and fully clean with clean, cold water. Then, immediately put the parts into the subsequent solution.

   6. When only electrolytic cleaning is to be used, do as follows:

      1. Immediately put the parts fully in cold water for a few seconds to rinse them.

      2. Put the parts fully in hot water at 149 to 203 deg F (65 to 95 deg C) until the parts are at the same temperature as the hot water.

      3. Remove the parts from the hot water.

      4. Dry with a blast of clean, dry compressed air.

   7. If necessary, de-embrittle the steel parts (refer to Introduction) as follows, or as specified in the Engine Manual.

      1. Heat treat the parts at 374 to 410 deg F (190 to 210 deg C) for two hours.