CERAMIC INFUSED SHAFT SLEEVES

TOUGH TECHNOLOGY FOR TOUGH CONDITIONS

The Slurrytech CIS shaft sleeve is an exciting new technology wear coating that offers amazing robustness and wear life unmatched by existing technology and products.

The CIS product offers a uniformed particle matrix able to withstand thermal cycling without the catastrophic delaminating problems normally associated with spray coatings, CIS performance far exceeds HVOF, PTA, Laser & others coatings.

Utilising revolutionary spray technology in the coating process our sleeves avoid many of the problems associated with conventional ‘thermal spray’ processes offering the following advantages:

• High density, uniformed carbide microstructure.
  

• Major reduction of inclusions, porosity and oxidisation.
   

• Near metallurgical bond strength.
   

• Thermal cycle stability.
   

• Reduced residual stresses.
   

• Retained properties of initial particles.
   

• High corrosion resistance to leaching and pitting.
   

• High hardness with excellent wear resistance.
   

• Excellent mechanical strength.
   

• Resists delamination through material hardness and property disassociation.

COMMON SLEEVE FAILURE MODES

Fatigue Fracture.

A common failure mode for coated shaft sleeves is Fatigue Fracturing. Fatigue fracturing occurs when a material is put under a repeat load cycle such as rotary movement with a high radial load creating a flexing effect and or torsional load.

In most weld coatings parent material of the sleeve is undercut to facilitate the weld / thermal inlay. This results in a metallurgical bond of a harder, high carbide matrix to a ductile substrate. In service torsional and radial loads are applied to the sleeve, the substrate with lower hardness and higher toughness can generally withstand these forces. The harder weld inlay however always has a lower fracture toughness along with inherent stress causing fatiguing and fractures in a spiral type tortoise shell pattern that depicts the loads being applied in service.

Traditional spray coatings such as HVOF suffers a similar fate as the harder coating is fractured and compromised.

The image below shows a typical failure mode for PTA shaft sleeve that is becoming more prevalent within the industry.

Matrix Failure.

Matrix failure occurs when a sleeves suffers from “wash out” which can happen long before they wear out. The binding matrix that holds the harder wearing carbides in place is washed away by either chemical attack or by submicron wear. This leaves the sleeve with a "fluffy" abrasive surface of exposed carbides which attack the packing materials.

Manufacturing Faults.

In an independently commissioned report on one of the most widely used sleeves it was discovered that the wear resisting carbides were simply not bound sufficiently in the matrix, in simple terms they were falling out like loose teeth. The root cause for this result is based in manufacturing control of heat / energy input along with shielding gas control which can compromise the matrix integrity.
 

COATING PROPERTIES

The following table gives an overview of different coating technologies and their properties.
 

Properties	SlurrytechTM CIS	Thermal Spray HVOF	Weld Overlay PTA	Plasma Spray
Bond Strength	High	Very Low	Very High	Low
Complex Geometries	No	No	Difficult	No
Abrasion Resistance	High	Moderate	High	Moderate
Erosion Resistance	Good	Low to Moderate	Moderate	Low
Corrosion Resistance	High	Low	Moderate	Low
Impact Resistance	Moderate	Low	Moderate	Low
Oxide Level / Porosity	Very Low / Very Low	High	Low / Low	High
Temperature Resistance	Moderate to High	Moderate	Moderate	Moderate
WC % Concentration	~ 85	~ 65 - 70	~ 65 - 75	~ 60
Metallurgical Bond	Infused Bond	No	Yes	No
Life Factor	1.8 - 4	1.0	1.5 – 2.5	0.8 - 1.0

MATRIX FEATURES

The micrographs below show CIS, PTA and HVOF matrix structures.

PTA and HVOF coatings have clearly defined phases of material between hard phase (Carbides) and the binder along with some matrix flaws of porosity and oxidization.

The CIS coating however presents a uniformed matrix with fewer flaws and a more uniformed microstructure.

CASE HISTORIES

CIS sleeves have been proven successful in some of the most arduous duty conditions.

High thermal cycling frequency which normally causes coatings to fracture and/or delaminate has minimal effect on the CIS sleeve.

Refinery Transfer

Pump: 8/6E-AH

Sleeve	Run Hours	Wear mm	Location / Failure	Conclusion
PTA	960	4.0	Uniformed across sleeve / Fractured	Replace
Laser	960	3.0	Uniformed across sleeve / Washout	Replace
CIS	1000	1.0 - 1.5	Localised at lip seal / Reuse	Reverse after another 1000hrs

Cost Impact: 1 cycle = 1000hrs

CIS sleeve =  1 sleeve x 1.4 cost / 1 cycle life = Cost Factor = 1.4

PTA sleeve = 2.5 sleeve x 1.0 cost / 1 cycle life = Cost Factor = 2.5

Conclusion: CIS Sleeve has higher initial cost but is more almost twice as cost effective as PTA and other materials.


Gold Tailings

Pump: 6/4E-AH

Sleeve	Run Hours	Wear mm	Location / Failure	Conclusion
PTA	2500	3.0	Localised gouging / Early fracture pattern	Replace
HVOF	1120	?	Uniformed ? / Delaminated coating	Replace
CIS	2360	0.4	Uniformed across sleeve / Reuse	Reuse x 4

Cost Impact: 1 cycle = 9440hrs

CIS sleeve =  1 sleeve x 1.4 cost / 1 cycle life = Cost Factor = 1.4

HVOF sleeve = 4 sleeves x 1.0 cost / 1 cycle life = Cost Factor = 4.0

Conclusion: CIS Sleeve has higher initial cost but is more almost 3 times as cost effective as PTA and other materials.


Mineral Sands

Pump: 4/3D-AH

Sleeve	Run Hours	Wear mm	Location / Failure	Conclusion
PTA	500	1.5	Localised gouging / Fracture pattern & packing	Replace
HVOF	400	?	? / Delaminated coating & packing	Replace
Laser	600	0.8	Uniformed / Slight fracturing	Reuse?
CIS	1120	0.5	Uniformed across sleeve / Reuse	Reuse x 2

Cost Impact: 1 cycle = 2000hrs

CIS sleeve =  1 sleeve x 1.4 cost / 1 cycle life = Cost Factor = 1.4

Laser sleeve = 2.5 sleeves x 1.0 cost / 1 cycle life = Cost Factor = 2.5

Conclusion: CIS Sleeve has higher initial cost but is more almost twice as cost effective as Laser and other materials.


Please feel free to contact us and arrange to trial this exciting technology improvement in your slurry and solids handling pumps.