Shaft sleeves used in gland packing service are subject to abrasion damage from particles in the process medium that become embedded in the gland packing, and this can result in very high wear rates even with moderately clean process mediums. The wear mechanism is predominantly low-stress abrasion accelerated by abrasion-corrosion; therefore hardness and corrosion resistance of the sleeve surface are the key selection criteria.
Generally the gland packing requires a controlled amount of process medium leakage to cool the gland sleeve from the frictional heating generated between stationary packing and rotating sleeve. If there is insufficient cooling by process medium, very high sleeve surface temperatures and thermal gradients can be reached, which can damage a ceramic coating.
Our tungsten carbide based coatings provide excellent abrasion and corrosion resistance against harsh particles coming in contact with the sleeves. These coatings can be applied with HP-HVOF process that produces a dense and homogeneous coating through repeated and controlled deposition. The cross section of sleeves being very thin, necessary precautions are taken during the coating process to ensure that the temperature is controlled and sleeves are not distorted. The coatings are ground and polished with at most precision to achieve desired size and surface finish. Certain applications demand deposition of nickel based materials such as Colmonoy by Spray and Fuse method whereas others demand deposition of cobalt based material through PTAW process. For certain non-critical applications even ceramic coated sleeves are used.
We can provide complete coated and cladded pump sleeves as per customer requirement. We have in-house setup to manufacture sleeves of various sizes and meet high volume demands.
|Coating Properties||PIC C53||PIC C832||PIC DC09||PIC B02|
|Process||PTAW||Spray and Fuse||HVOF||Plasma|
|Micro Hardness (HRc)||42 - 48||58 - 64||72 - 74||68 - 72|
|Coating Application||Erosion and Corrosion Resistance||Abrasion Resistance||Abrasion and Corrosion Resistance||Abrasion and Corrosion Resistance|
|Surface Finish||< 0.4 Ra µm|