Hard Chrome Plating

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Project Description

HARD CHROME PLATING

Hard chrome plating is an electroplating process in which chromium is deposited from a chromic acid solution. Thickness of hard chrome plating ranges from 2 to 250µm. Various types of hard chrome include micro-cracked chromium, micro-porous chromium, porous chromium and crack free chromium. It is essential that the micro-cracked and porous coatings have a minimum thickness between 80-120µm in order to confer adequate corrosion resistance. Micro-cracked chromium has a Vickers hardness of 800-1000 kg/mm2, while crack-free chromium has Vickers hardness between 425-700 kg/mm2. The formation of micro-porous chromium is achieved by a specialised plating method involving the use of inert suspended particles. Porous chrome plating is developed by etching electrodeposited chromium. These are designed to retain lubricant, for sliding and bearing type applications.

Chrome plating is used for wear and corrosion resistance in addition to its tribological (low friction) characteristics. However, there are environmental concerns associated with disposal of the plating solution. This has led to many users of chrome plating seeking alternative coating methods. One option is to replace hard chrome with high velocity oxy-fuel (HVOF) sprayed coatings of cermet materials such as WC/Co (Tungsten Carbide/Cobalt). The HVOF sprayed coatings can offer superior wear and corrosion protection. A comparison of properties for HVOF sprayed WC-12Co versus hard chrome is shown in the table below.

Hard Chrome Platting
Hard Chrome Platting
Hard Chrome Platting
Hard Chrome Platting

HARD CHROME PLATING TECHNOLOGY

THE PROCESS

Hard Chrome plating is an electrolytic method of depositing Chrome for engineering applications, from a Chromic acid solution. Deposits can be applied from .25 – 1,000 microns thickness for a wide range of applications. The thinner deposits being used to substantially increase the life of components in wear applications or corrosive environments, and the thicker deposits being used for salvage and repair of worn, damaged or mis-machined components. Hard Chrome is classed as a “COLD” process; the operating temperature of 50 – 60°C ensures no detrimental effects to the physical or mechanical properties of the base materials.

Hard Chrome can be deposited successfully and advantageously onto most metallic substrate materials

  • Hard Coating
  • Non Fretting Anti-Galling
  • Low Friction
  • Super finishing to Mirror Finishes
  • Excellent Wear Resistance
  • Thinwall Technology or Heavy Build-Up
  • Good Corrosion Resistance
  • 0.25 – 1,000 Micron Thick
  • “Cold” Process
  • Grinding and Polishing Service

THE PROPERTIES

HIGH HARDNESS

Electro-deposited Chrome is extremely hard, with typical values of 850 – 1050 HV (63 – 70HRc), hence the term “Hard” Chrome. This makes it an excellent coating for wear resistant and abrasion resistant applications such as Moulds and Dies, Punches, Bearing and Seal surfaces, and sliding components.

LOW COEFFICIENT OF FRICTION

Hard Chrome has a very low coefficient of friction, approx. one half that of Steel. The coefficient against Steel of 0.16 lubricated (0.21 dry), makes it ideally suited for such applications as Bearing and Seal surfaces, and machinery components

WEAR RESISTANCE

​​The high hardness and low frictional properties of Hard Chrome provide it with extremely good resistance to abrasive and erosive wear, extending the life of components such as Moulds, Dies and Punches etc, up to ten times in most cases.

CORROSION RESISTANCE

​​Hard Chrome has an extremely high resistance to atmospheric oxidation, and a good resistance to most oxidising and reducing agents (with the exception to Chlorides and other Halides), hence its wide-spread use in the Food and Chemical Industries

SACRIFICIAL WEAR LAYER

Since Hard Chrome deposits are readily removed with chemical strippers, without detrimental effect to the base material, the part can be stripped and re-plated repeatedly, when wear shows, without loss or damage to the base part. This is a significant advantage for high wear, high cost parts such as Plastic Moulds and Dies where abrasive filled plastics are used.

MACHINING

​Hard Chrome deposits can be successfully finished by grinding, finishing or polishing.

LARGE CAPACITY

  • Hard chrome Engineering offer some of the largest capacities available
  • Lifting capacity By
  • 15 tone & 10 tone lifting facility
  • Grinding Machine Capacity By.
  • Dia 50mm to1000mm Dia X 6000mm Maximum
  • Plating tanks Capacity By
  • Dia -1200mm X 6500mm Length.
  • Dia – 600mm X 4000mmLength.
  • L 1100 X W 800 X D 1800

LARGE CAPACITY

  • Hard chrome Engineering offer some of the largest capacities available
  • Lifting capacity By
  • 15 tone & 10 tone lifting facility
  • Grinding Machine Capacity By.
  • Dia 50mm to1000mm Dia X 6000mm Maximum
  • Plating tanks Capacity By
  • Dia -1200mm X 6500mm Length.
  • Dia – 600mm X 4000mmLength.
  • L 1100 X W 800 X D 1800
Hard Chrome Platting
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