Hardide coatings are used in petrochemical applications to protect critical parts from abrasion, corrosion and chemical attack as well as galling and seizing.
Hardide coated hybrid hydrodynamic/hydrostatic radial and thrust bearings have been used by Alfred Conhagen, Inc. in eight-stage and six-stage high-performance centrifugal pumps designed for high temperature refinery service. At the product temperature of 450°F (230°C) both the octane and diesel have poor lubricity. Alfred Conhagen’s concern in both applications was entrained solids and thermal growth of the close clearance components. In the diesel application, there was pipe scale and some coke fines, and the octane pump occasionally had catalyst carryover which can quickly destroy fine clearances.
The Hardide coated bearings have been in service for three years during which time they have experienced some moderate-to-severe solid ingestion, yet the coated bearing surfaces remain in excellent working condition with a number of parts showing no signs of wear at all. The substrate is 410 stainless steel to match the coefficient of thermal expansion of the other parts to maintain close clearance over a range of temperature. With the Hardide coating there has been no galling or cracking of the coated surfaces.