Reason for use:
During use, the clutch pressure plate will wear and form heat cracking on its operative face taking it below acceptable tolerance.
By using the Metallisation arcspray process the deposit poses a higher degree of bond strength than most other thermally sprayed deposits. The use of compressed air and electricity means more economic coatings.
It is possible to rebuild the pressure plate face back to its original size giving savings of up to 50% of their replacement cost.
The reclamation of clutch pressure plates for cars, tractors and commercial vehicles are all possible by using the Metallisation process.
Equipment
Materials
Metallisation 45E 0.8% High Carbon Steel
Produces extremely wear resistant coatings with very low stress levels Hardness 38Rc
Cleaning
(A) Steam clean if equipment available
(B) Degrease by solvent vapour process if equipment available
Preliminary Inspection
Check for cracks or faults taking plates below the manufacturer’s recommended tolerances
Preparation
Preliminary Machining
Rough grind or turn to remove surface imperfections, heat cracking, etc.
Pre-machine plates to a depth of .50mm to 2.00mm. Depth of machining is dependant on surface quality of plate.
Blasting
Thoroughly blast surface to be sprayed with clean chilled iron grit grade G24.
A surface profile of between 75µm-100µm should be achieved. See Technical Bulletin Nº 5.2.2 for information on gritblasting. It is important that the surface to be sprayed should not come into contact with hands, oil, grease or any other contaminants, which may cause bond failure after spraying. Delay between blasting and spraying should not exceed 20 minutes.
Bonding and Simultaneous Spraying of 45e
(A) The arcspray equipment should be set up in accordance with the Metallisation Manual for the spraying of 45E (0.80% Carbon Steel).
(B) The area to be sprayed should be cleaned with a vacuum cleaner or a clean, dry air blast to remove any loose particles of dust or grit.
(C) The first 75µm-100µm should be applied at a close range (typically 100mm) and lower air pressure to achieve a higher bond strength.
(D) The coating should be applied evenly and as close as possible to 90º from the rotating surface of the component.
Spraying Parameters for Bond Spraying
(i) Material: 45E, 0.8% C High Carbon Steel 100mm
(ii) Range: 100mm
(iii) Nozzle Air Pressure: 3.7 bar (55 psi)
(iv) Volts Before Spraying: 38V
(v) Volts During Spraying: 34V
(vi) Current: 200A
Main Deposit
(A) Apply 45E final deposit to specified required thickness plus a grinding allowance of 375µm-500µm above required finished size.
(B) The pressure plate should be rotated to give a minimum surface speed of 20m/min (60ft/min) throughout the spraying process.
(C) The ARC pistol should be evenly traversed over the component ensuring total coverage and even thickness.
(i) Range: 150mm
(ii) Nozzle Air Pressure: 4.3 – 4.6 Bar (65-70 psi)
(iii) Volts Before Spraying: 38V
(iv) Volts During Spraying: 35V
(v) Current: 250A-300A
Note: Parameters may differ in accordance with type and length of power cables and hoses being used.
