Worn Shaft Repair by Metallizing

A worn journal, bearing seat or seal face does not always require a new shaft.

Request a Shaft Repair Quote Share a Drawing on WhatsApp
  • Arc and flame spray
  • Reclamation of worn out parts
  • At our Bengaluru units
An operator spraying metal onto the journal of a steel shaft mounted on a lathe

How Metallizing Rebuilds a Worn Shaft

Shafts wear where they run: bearing journals, seal and sleeve seats, coupling fits and wear-ring surfaces. Metallizing repair replaces the lost metal by spraying molten or semi-molten material onto the worn area, which is then finished to size.

Because the part is not welded, the heat input is far lower than with weld build-up, which helps to limit distortion on long or slender shafts. The sprayed layer bonds mechanically to a freshly blasted surface.

We carry out metallizing repair of worn shafts. The route is chosen from the wear, the duty and the base metal.

Diagram of an arc spray gun: two charged wires meet and arc at the nozzle, and compressed air atomises the molten metal and carries it onto the workpiece as a coating
In arc spray, two wires are melted in an electric arc and propelled onto the prepared surface, building up worn metal layer by layer. Flame spray builds up the surface in the same way, using a gas flame.

When Metallizing Repair Is Appropriate

Worn Journals and Seats

Bearing, seal and sleeve seats that have lost diameter but are otherwise sound.

Long or Slender Shafts

Parts that could bend or distort under the heat of weld build-up.

Shafts That Are Difficult to Replace

Large, special or long-lead shafts where reclaiming the surface is faster than making a new part.

Upgrading the Surface

A harder or more corrosion-resistant coating can be applied where the original surface wore quickly.

Repair Routes

The route and coating material are selected for each shaft on the basis of the amount of wear, the duty and the base metal.

Arc spray
Wire build-up of larger areas at a high deposition rate.
Flame spray
Wire or powder build-up at our facilities in Bengaluru or at your site. See flame spray.
Surface preparation
Undercut and clean, then grit blast for bond
Finishing
Machined or ground back to the drawing size
Inspection
Measurement of the finished diameter and a visual check of the coating

Process Steps

Diagram in six stages: a worn shaft is measured, undercut on a lathe, grit blasted, built up with sprayed metal, machined to size, and inspected
Why It MattersBuilding up a worn journal and machining it to size returns a shaft to service for far less time and cost than a new one. Illustrative diagram.

  1. Inspect and Measure

    We measure the wear and the straightness of the shaft, and examine the base metal, so that the repair route can be chosen.

  2. Undercut and Clean

    The worn surface is cut back where necessary so that the coating can be built to a usable thickness. All oil and dirt are then removed.

  3. Grit Blast

    Clean, sharp grit blasting gives the sprayed metal a rough surface to which it can adhere.

  4. Spray Build-Up

    The chosen coating is sprayed in passes, with the surrounding area masked, until it stands above the final size.

  5. Machine to Size

    The part is then machined or ground back to its drawing size and surface finish.

  6. Inspect

    The finished diameter and the coating are checked before the shaft is returned.

Applications

Any rotating shaft that wears at a fit or seal face can be considered. Please share the drawing and the wear details, and we will advise whether spray repair suits the part.

  • Pump shafts and sleeves
  • Fan and blower shafts
  • Roll necks and rolls
  • Motor and gearbox shafts
  • Bearing journals and seal seats

Frequently Asked Questions

How does metal spray shaft repair work?
The worn area is cleaned and grit blasted. Metal is then sprayed on to build it up above size, and the part is machined or ground back to its drawing size.
Is a sprayed repair as good as a new shaft?
The answer depends on the operating duty of the component. For many wear and corrosion problems it restores the surface well. For shafts with heavy bending or torsional loads, we will advise if spray repair is not suitable.
Which spray process is used for shaft repair?
Arc spray or flame spray, depending on the wear, the thickness to be rebuilt and the service conditions. We recommend one after examining the shaft.
Can a shaft be repaired on site?
Yes. Flame and arc spray equipment can travel to site.
What should be provided with an enquiry?
The drawing, the material, the worn dimensions and the fit or tolerance to which the shaft must return. Photographs of the wear are also helpful.

Related Services

Flame spray

Wire and powder coatings, in the workshop or on site

Thermal spray zinc

Sacrificial corrosion protection for structural steel

Coating inspection and testing

Thickness, adhesion and surface testing with full records

Send Shaft Details for a Repair Quote

Share the shaft drawing, the worn diameters and photographs of the wear. One of our engineers will confirm whether metallizing suits the repair and quote for it.

Call+91 96861 11973 WhatsAppPhotographs and drawings Emailthermalspray@mythrimetallizing.net
  • Reply within one working day
  • Drawings kept confidential
  • Email acknowledgement

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