Processes

Thick chrome plating

Hard chrome has a crystalline structure which, in comparison with other surface treatments, gives the deposit unique properties that are indispensable for various industrial applications. The main qualities are high resistance to wear, whether dry or with lubricant, by compression or abrasive action, and high resistance to chemicals.
Thick chrome plating, or hard chrome plating, is a surface treatment that deposits a chrome coating with a thickness of 0.005 to 1 mm on articles made of aluminium alloys and standard metal alloys (iron, stainless steel, copper, brass).

COATING FEATURES

  • Thickness 0.005 to 1 mm
  • Surface hardness > 1,000 HV
  • 1000 h NSS
  • Scratch resistance
  • Wear resistance
  • Non-magnetic deposit
  • Melting point 1,900°C
  • Frame treatment

TREATABLE WEIGHTS AND MEASURES

  • Minimum dimensions: a few millimetres
  • Maximum cylinder dimensions: 1,300 mm – ø 350 mm – weight 450 kg
  • Maximum dimensions of parallelepipeds: 1,850x350x1,300 mm – weight 450 kg

TECHNICAL DETAILS

Deposit type Technical
Hardness (HV) 850-1100
Magnetic properties Non-magnetic
SpessObtainable thicknesses (mm) 0,005-1 mm
Toxicity NO
Treatable materials Al; Cu; Fe; Inox

Deposit type: Technical
Hardness HV: 850-1100
Magnetic properties: Non-magnetic
Obtainable thicknesses (mm): 0.005-1 mm
Toxicity: NO
Treatable materials: Al; Cu; Fe; Inox

SECTORS OF APPLICATION

  • Food sector (cooking plates, chrome fry top)
  • Textile sector (wire tensioners, wire guides, feeders, plates, heads, drive rings, cylinders, grippers and wire guides, washers, pulleys, sliding plates, taping machines for textile processing, shrouds, plates, sinker rings, covers, cylinders)
  • Plastics sector (roller, guide)
  • Food sector (cooking plates, fry tops)
  • Pharmaceutical sector (plates, folders, strips, sealing bars, dispensers for filling machines (solids/liquids/creams), packing machines, thermoforming machines, blister machines, capsuling machines)
  • Hydraulics and pneumatics (pins for cranes/hoists, valve bodies/pistons and rods for hand pumps, gears, pistons, cylinders)
  • Weapons sector (rifle barrels)
  • Automotive sector (cores and canisters for LPG/CNG injector bodies, pins and linkages for wipers, injectors, heads, cylinders, pistons)
  • Industrial irrigation sector (hub, brake)
  • Motorcycle sector (fork, hub, shock absorber, spring)
  • Wood sector (drive ring, roller)

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FAQ

Hard chrome plating or thick chrome plating?

Hard chromium plating, also known as thick chromium plating or functional-technical chromium plating, is a galvanic process aimed at electrochemically depositing a surface coating of chromium metal on the part.
The electrodeposition process, which is carried out by introducing part or all of the item to be coated into special equipment (in most cases, a chromosulphuric electrolyte), produces surface coatings of considerable hardness, resistant to wear and corrosion, with thicknesses ranging from a few tens of microns to 1000 microns.
The main feature of the electrolytic chromium deposit is its high resistance to wear, whether dry, under lubrication, compression or abrasives.

What types of materials can be processe?

Hard chrome plating is applied directly to substrates consisting of:

  • Iron
  • Aluminium and its alloys after special preparation
  • Carbon steels, also heat-treated
  • Stainless steel
  • Cast irons after blasting
  • Copper and its alloys
  • Brass
Is the geometry of the part to be treated important?

Yes, thick chromium plating is applied using a highly electrolytic process and therefore has difficulty when faced with complex geometries, especially if high coating thicknesses are required. Deposition on undercuts and inside holes and threads is very difficult. On the other hand, on the perimeter surfaces of parts, a “tip effect” occurs, which can be reduced by means of specific masking.

What is the environmental impact of chromium? What about chromium 6?

Although not well-known in the collective imagination, thick chromium plating is one of the processes which (if handled correctly) has a much lower environmental impact than most galvanic processes. No water containing chromium is sent to the purification plant, as 100% of the water consumed in the backwashing lines is then reused in the same chromium plating process, recovering water and raw material. All equipment is vacuumed and the airflow is treated with a scrubber, then the air is “washed” in counterflow by water, which is also used 100% to replenish the levels in the process tanks.

Food quality chromium, really?

In addition to high hardness and excellent wear resistance, the deposit provides considerable resistance to scoring and, in particular, to corrosion.
This characteristic, due to the formation of a passivated layer on the deposited surface, similar to that which develops for stainless steels, is proportional to the thickness of the deposit, its adherence to the substrate and its porosity.
Thanks to these characteristics (after specific tests on each family), thick chrome plating is also suitable for use in the food and beverage sector, such as for fry tops on cooking plates.

Is thick chrome plating done by rotary barrel?

Chromium-plating takes place due to the passage of large amounts of current (density), so the objects to be chromium-plated must be supported with suitable electrical contact points achieved with support provided by frames (static).

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