Metal Spraying, Hard Facing and Surface Coating for Wear Resistance and Repair

Actis (UK) Ltd

Unit 27, Hamilton Road, Sutton in Ashfield,

  Notts, NG17 5LD  United Kingdom

Tel 01623 511542     Fax 01623 553542

e-mail actisuk@aol.com


 

 

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Rotary Lobe Pumps – Rebuilding of Worn Rotors and Housing

         Overview

The pump components are rebuilt using Nickel-Chrome alloys, which have a high resistance to wear and corrosion. Nickel Chrome alloys are harder than the Stainless Steel or Waukesha alloys used by the pump manufacturers.

As a result, the service life of a rebuilt pump is actually greater than that of a new pump. 

          Rebuilding Procedure

 The worn components are degreased, cleaned and then coated with metal and alloy powders to the desired thickness.

       The coated parts are heated in a vacuum furnace at a uniform rate until the coatings melt partially and fuse to the parent metal. They are then cooled uniformly to avoid distortion. The rebuilt components are finally machined to their original size specification.

Conventional welding techniques, which cause distortion of the parts due to localised heating and cooling, are not used in the process. Throughout our rebuilding process, local temperature gradients are avoided to ensure that no deformation of the components occurs.

The Boron and Silicon content of the Nickel Chrome alloys used for rebuilding imparts high wear resistance. Because the alloy is fused to the parent metal, there is no danger of the coating peeling off in service. There are naturally limitations to the thickness of coatings  which can be successfully applied, usually around 1.5mm. Components worn by more than 1.5mm require special techniques for rebuilding. This involves applying an initial coating of 1.5mm thickness of a high melting point alloy. This is then followed with a second coating of 1.5mm thickness of a lower melting point alloy, which can then be machined to original dimensions

 

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Last modified: October 29, 2001