General Industry

Repair Applications: Printing Equipment

The primary applications include filling damaged or worn areas on stainless steel or iron, web-offset or flexographic press cylinders, and filling in porous chromium plate or damaged areas on steel blanket cylinders.

A 2.4m (8') diameter x 2.4m (8') long stainless steel web offset impression cylinder had been accidentally damaged by a small wrench. A 76mm (3") long area was pressed in almost 2mm (0.080"). This defect was dished out and filled with several layers of copper. The copper and adjacent stainless steel surfaces were then plated with nickel and were ground to required surface finish and size.

Intaglio impression rolls operate at extremely high printing pressures. They are plated with approximately 1.5mm (0.060") of chromium to get the best possible surface. Isolated pits in the chrome, barely visible to the naked eye, were a cause for rejection. These pits varied from 12mm to 38 mm (0.005" to 0.015") in diameter. A copper deposit was applied, followed by an overlay of cobalt which gave a good color match with chromium. Light polishing with crocus cloth completed the repair.

Plate and blanket cylinders with accidental damage, imperfections in the base material, or in-service wear are good candidates for using the SIFCO Process.

Repair Applications: Electric Motors and Generators

The repair of electrical generating equipment presents many areas in which the SIFCO Process of Selective Plating can be used with great success. The primary application areas are the bearing housing (end bell) and the rotor journal.

End bells, which house the bearings that support both ends of the motor shaft, experience fretting corrosion during operation. The SIFCO Process is used to plate these bores to size with copper, tin, or nickel. Machining the bores, prior to plating, is usually only necessary to reestablish concentricity.

Plating a worn bearing housing can take less time and be more efficient than alternative methods such as sleeving or thermal spray processes.

DC motors and generator slip rings can develop copper oxide films which reduce electrical conductivity and cause arcing and pitting especially during locked motor start-up. Excessive damage occurs in highly corrosive environments, such as in the bleaching areas of pulp and paper plants. Plating 2.5m (0.0001 in.) of rhodium and then 1.3m (0.00005 in.) of gold onto the refinished commutator extends brush life and maintenance intervals.

Repair Applications: Marine

This portable process can be used in the shop to repair worn bearing journals and housings on smaller generators, pumps and fans. It can be taken aboard a ship for in-place repairs of large, hard-to-move components such as propeller shafts, bearing seats, and turbine casings.

• A 0.020" thick nickel deposit was applied to a spun bearing journal, saving a $100,000 Pinion Gear Shaft.
• A Nickel-capped copper deposit was applied, in place, to a reduction gear box bearing area, saving valuable time and eliminating the need to cut away a section of the ship for removal and repair of the component.
• Plating a heavy nickel deposit on a mismachined lower cylinder sleeve seat on a large marine diesel engine allowed a standard sleeve to be used and saved the cost and delay associated with the manufacture of a special sleeve.
• Babbitt plated on the 26" ID of a mis-machined line shaft bearing eliminated the need to remove and recast the babbitt.
• Severe damage to the cylinder liner retention bores within a diesel engine block was repaired by plating multiple layers of copper which were hand-worked back into tolerance and then capped with nickel for protection.
• Pumps: bearing housings, impeller bores, shaft bearing journals and seal areas
• Valves: gates, discs, valve stems, seal rings
• Propulsion components: propeller (line) shaft journal and seal areas, line shaft bearings, bearing saddles
• Electrical: motor generator bearing housings, rotor journals, commutators, bus bars
• Power generation: steam turbine bearing journals, flange faces, diesel engine cylinder liners, connecting rod bores, crankshaft journals
• Structural: watertight door knife edge sealing areas, hatch covers, hull inserts, access doors
• Hydraulics: steering gear cylinders and rods

Repair Applications: Pulp and Paper

• SUCTION ROLLS: bearing diameters
• DRYER ROLLS: bearing diameters, heads, surface defects caused during maintenance 
• PUMPS: bearing housings, impeller bores, shaft bearing journals and seal areas
• ELECTRIC MOTORS: bearing housings, rotor journals, commutators, bus bars
• POWER GENERATING EQUIPMENT: steam turbine bearing journals, flange faces, diesel engine cylinder liners, connecting rod bores, crankshaft journals

A Case History

Problem: Steam heat was applied too rapidly while starting up a 4.5 m (15 ft) long, 4.5 m (15 ft) diameter Yankee Dryer. The result was that the inner race on a roller bearing cracked, which damaged the journal. Approximately 95% of the journal area required build-up material. The amount of material required on 65% of the area was 25 microns (0.001 in.) to 508 microns (0.020 in.) per side. Approximately 30% of the area required 508 microns (0.020 in.) to 2250 microns (0.090 in.) on a side where broken up fragments pressed into the journal. The tapered journal had a diameter of 330 to 356 mm (13 to 14 in.) and a length of 203 mm (8 in.).

Solution: Selective plating was selected as the repair method. The plating of the journal began with mechanical preparation of the surface using flap and polishing wheels to remove sharp projections, oxides, baked on films, etc. Afterwards, the area was solvent cleaned and masked off. The area was then cleaned, etched, desmutted, nickel flashed, and copper-plated 625 microns (0.025 in.) thick over the entire surface. There was some surface roughness at this point, so flap and polishing wheels were again used to improve the surface. The journal was measured using a micrometer, and areas where there was sufficient stock were masked off so that additional plating could be applied only where it was required.

The remaining area was cleaned, etched and copper plated with an additional 625 mm (0.025 in.) thickness. A total of 4 layers of copper was applied in this manner. This provided sufficient stock over the entire journal. The time elapsed, from originally viewing the part to this point, was 40 hours.

The journal was then machined with a single point tool approximately 50 microns (0.002 in.) undersize. Nickel 25 microns (0.001 in.) thick was finally applied to give a harder, anti-galling surface.

Result: After the job was done, the unit was placed back in service. After ten years, there has been no problem with the repair. The bearing was taken off once and, because no damage was noted, the same bearing was replaced.

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Repair Applications: Chemical Plants

SIFCO Process saves chemical plants time and money in maintenance turnarounds!

The SIFCO Process for selective electroplating is very useful in helping chemical and petrochemical plants execute fast, efficient, and cost-effective maintenance turnarounds.

By utilizing the SIFCO Process, maintenance engineers, planners, and general contractors can repair pumps, motors, flanges, valves, and other components on-site by applying metal to the components without the heat or distortion of welding or flame-spraying, and many times plating to-size without post-machining. The SIFCO Process is a portable process, plating up to 100 metals and alloys without the use of tanks. It allows you to rebuild shafts and stems that are worn or pitted, in many instances without complete disassembly. Electric motor end-bells can be re-sized quickly and easily usually without post-machining so it is faster then sleeving. Corroded flanges can be filled and capped with a more corrosion resistant material without removing the flange. Wear rings can be coated with a metal that is more wear-resistant thereby increasing the component's useful life.

The process is up to 60 times faster than tank plating, so rapid metal build-ups are achievable. And because the process is true electrolytic plating, the metallic bond is atomic in nature, resulting in adhesion superior to processes such as flame spraying.

The SIFCO Process has been used in chemical plants on various process components resulting in significant savings versus other repair methods or replacement. Here is just a sample of the savings that can be achieved:

We can sell you the equipment, supplies, and in-depth training so you or your contractors can use the SIFCO Process to effect repairs right at the plant. SIFCO can also provide experienced service technicians to do the work for you either on-site at the plant, or at one of our facilities worldwide.

SIFCO is interested in hearing from you if you think the SIFCO Process might help you meet some of the challenges you face in maintaining your plant. Please don't hesitate to contact us:

SIFCO USA	info@sifcoasc.com	+1 216-524-0099
SIFCO UK	plating@sifco.co.uk	+44-1527-557740
SIFCO France	sifcoasc@sifcoasc.fr	+33-1-60-94-07-87
SIFCO Sweden	info@sifco.se	+46 248-12525

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