Hard Chrome Plating
Hard chrome plating demonstrates excellent hardness and lubricity, and is the premier engineering choice to reduce friction, minimize wear and prevent galling. These characteristics are applicable for critical engineering applications, including: machine tool cutting surfaces, cylinder bores, strut rods, crankshafts and hydraulic shafts. Hard chrome is also applied to molds because of its low surface energy and resultant release properties. Chem Processing can hard chrome plate steel, aluminum, or copper materials, as well as many exotic alloys. In cases where parts require other finishes in addition to hard chrome, Chem Processing can selectively apply cadmium plating, electroless nickel or other finishes.
Note: There are two distinct types of chromium plating, bright chromium plating (decorative) and hard chromium plating (engineering). Chem Processing supplies standard hard chrome and thin-dense chrome plating but not decorative chrome plating.
Chem Processing Inc. hard Chrome Plating Capabilities:
- Typical Plating Thickness Range is 0.00005 to 0.02500 inches. For information on plating over 0.025 in., please contact Chem Processing, Inc.
- Hydrogen Embrittlement Relief: parts with a hardness of 36 Rc or greater will be baked a minimum of 3 hours at 375° F to relieve entrapped hydrogen
- Thickness Analysis on a Fischer Technology XDL-B X-Ray Fluorescent Spec
- SAE AMS 2406
- HS 246 (UTC Aerospace Systems/Hamilton Sundstrand)
- PN 13.06 (UTC Aerospace Systems/Hamilton Sundstrand)
- PS 101 (UTC Aerospace Systems/Hamilton Sundstrand)
Properties of Industrial Hard Chrome:
- Hardness: Plated chromium is extremely hard. A conventional bath will yield a Vickers diamond pyramid hardness of 900-1200.
- Very Low Coefficient of Friction: Hard chrome plating offers extended wear life and exhibits excellent release characteristics in mold applications.
Applications of Industrial Hard Chrome:
- Automotive: pistons, shock absorbers and other parts that see high cycles over long periods of time are hard chrome plated for durability and lubricity.
- Firearms: interiors of gun barrels are hard chrome plated.
- Aerospace: landing gear components are hard chrome plated in both OEM and MRO applications. Aluminum piston heads are hard chrome plated to offer optimal performance with minimal weight. Actuator components are hard chrome plated to reduce wear and extend service life.
- Machine Tools: drills, taps, dies, extrusion screws and rolls are hard chrome plated to extend life and improve performance.
- Gears: hard chrome plating prevents galling and extends life in low-friction applications.
- Salvage: hard chrome plating can be used to restore worn parts to their original dimensions or bring mis-machined parts into tolerance.
- Plastic Molds: hard chrome plating provides anti-stick/release properties for plastic molds across all industries.
RECOMMENDATIONS FOR FINISH GRINDING TO SIZE:
Chem Processing, Inc. does not offer grinding services but this is often an operation performed to bring a hard chrome plated deposit to desired dimensions. Extra "grind stock" will be applied, typically around 0.002" unless otherwise specified. Additional buildup in the form of nodules may also occur at edges when heavy deposits are being applied.
For reference, Heavy Deposition by J.D. Greenwood (Draper, 1970 pg. 184) recommends: When ground the metal has a bluish white spark and overgrowth soon cuts ridges in the wheel. It must be remembered that the heat created on grinding can cause the occluded hydrogen to expand violently, and thus crack the deposit severely. Thus heavy cuts must be avoided, particularly on parts which are going to be highly stressed or are going to be in service under corrosive conditions. Normally cuts should be in the region of 0.0004" deep, in the special cases reducing this to 0.0002" deep for minimum cracking. Additional recommendation is given for removing "overgrowth": The excess metal should be removed by working from the center of the shaft outwards; this will prevent chipping of the deposit.
Chem Processing Inc. offers industrial hard chrome plating services to Illinois, Wisconsin, Iowa, the Midwest and beyond. CPI is strategically located by highway routes to Chicago, Milwaukee, Madison,St. Louis, and Minneapolis. The CPI facility is minutes from Rockford Chicago International Airport, a major Midwestern air freight hub, enabling efficient door-to-door delivery across the United States or across the globe.