Nickel-plated ISO 6020/2 cylinders — replacing all-stainless cylinders for the food and pharmaceutical industries
Electroless nickel-plated Conforti hydraulic cylinders to ISO 6020/2 (the CD NK / DK NK / MD NK series) are a cheaper and faster-available alternative to cylinders made entirely from stainless steel. A 20 µm nickel coating on the cylinder body combined with a chromed stainless piston rod provides corrosion resistance equivalent to 1200 hours in salt spray (rating 10). The coating contains no heavy metals or ammonia — it is suitable for the food and pharmaceutical industries, for washing machine structures and for water works. Bores Ø 25–200 mm, 160 bar (240 bar test), stroke up to 4000 mm, every unit tested to ISO 10100. Supplied by hydraulika.store, the authorised distributor of Conforti Oleodinamica for the Czech Republic, Slovakia and the EU.
Article contents
Why replace an all-stainless cylinder with a nickel-plated one
An all-stainless hydraulic cylinder is expensive and takes a long time to manufacture. Yet in a large proportion of corrosive operations there is no permanent immersion in an aggressive medium, only washdown of structures, sanitation, moisture or salt spray — and for that a cylinder with an electroless nickel-plated body and a chromed stainless piston rod is enough. According to the Conforti catalogue, the nickel-plated version (NK) is designed specifically as an alternative to cylinders made entirely from stainless steel: it provides comparable corrosion protection at a lower price and with a shorter lead time.
The result for the operation: the same installation as the standard CD / DK / MD series, a direct replacement without machine modifications, and resistance that can be backed by a figure — 1200 hours in salt spray with a rating of 10.
What the NK nickel-plated version is
NK is a surface treatment of the standard tie-rod cylinders to ISO 6020/2. The entire cylinder body — the heads, the flange plates, the tie-rods and the cylinder barrel — is covered by a layer of electroless nickel, and the piston rod is chromed stainless (RRX).
- Nickel 20 µm — high adhesion and a uniform layer, protecting even edges and threads.
- 1200 h in salt spray, rating 10 — the highest degree of corrosion resistance per the catalogue.
- No heavy metals or ammonia, low environmental impact — suitable for the food and pharmaceutical industries.
- ISO 6020/2 (DIN 24554), tie-rods — bores Ø 25–200 mm, 160 bar (240 bar test), stroke up to 4000 mm.
- Media: mineral hydraulic oil, phosphate esters, water-glycol (HFC).
- Series: CD NK / DK NK (tie-rod) and MD NK (with a magnetic position sensor). Servo cylinders are not supplied in the nickel-plated version.
- Every cylinder is tested to ISO 10100 before delivery.
Nickel-plated NK vs. all-stainless cylinder — comparison
| Aspect | Nickel-plated NK cylinder | All-stainless cylinder |
|---|---|---|
| Corrosion protection | nickel 20 µm + stainless piston rod; 1200 h salt spray, rating 10 | stainless throughout (even below the surface) |
| Typical environment | washing with detergents, sanitation, moisture, salt spray, outdoor operation | permanent contact / immersion in an aggressive medium |
| Price | lower | higher |
| Lead time | shorter (ISO 6020/2 modular build) | longer |
| Installation | identical to the standard CD / DK / MD → direct replacement | per manufacturer |
| Internal cushioning | none (see limitations below) | per version |
| Test | 100 % to ISO 10100 | per manufacturer |
NK is not a replacement for all-stainless in the case of permanent immersion in a strongly aggressive medium — there, stainless throughout makes sense. For washdown, sanitation, moisture and salt spray, NK is a full-value and cheaper solution.
Where to use nickel-plated cylinders — real-world examples
Specific deployments where the NK version proves itself in practice:
- Food and pharmaceutical industries: from practice, e.g. pressing meat products into moulds and slicing and portioning cheese — operations with high hygiene demands where the cylinders are rinsed frequently. Nickel plating free of heavy metals and ammonia meets hygiene standards. Specific deployment: cylinders for the pharmaceutical and food industries.
- Washing and washdown of machine structures: applications where, for hygiene, machine structures including the cylinders are washed down regularly — the nickel-plated surface resists corrosion from washing cycles and detergents.
- Water works and gate/damper control: actuators for gates and sluices and other applications at water works — suitable for indoor and outdoor installations exposed to moisture and weather.
- Salt spray, marine and off-shore environments: 1200 h resistance in salt spray (rating 10).
- Electroplating, surface finishing and chemistry: contact with substances that promote corrosion.
Thanks to its identical installation with the standard CD / DK series, NK is ideal as a direct replacement for a corroded cylinder without switching to an all-stainless version. See an overview of the series on the nickel-plated cylinders for aggressive environments landing page.
What to verify before replacement (limitations of the nickel-plated version)
Nickel plating is a surface treatment that brings two design limitations — allow for them already at the design stage:
No internal cushioning. Applying the nickel slightly changes the tolerances of the internal bore diameters, so the nickel-plated version cannot be fitted with internal (integrated) end-of-stroke cushioning and offers only a limited number of ISO connection (mounting) options — per the catalogue, e.g. ME5, ME6, MS2 and MP5. Handle end-of-stroke cushioning with an external stop or with valves in the circuit; if you need integrated cushioning, choose a standard non-plated cylinder.
Position sensors — verify the IP rating. The MD NK series allows position sensors (SH and SR), but not all of them are suitable for every environment. Depending on the IP rating and the conditions (washing, salt spray, outdoor operation), it is sometimes necessary to fit the customer's own sensors, or to consult the solution with our technical team.
Both are handled for you by the configurator and a technical consultation — we supply the code, the CAD model and recommendations before ordering. Choosing a cylinder step by step is described in the article How to choose a double-acting hydraulic cylinder.
Frequently asked questions
Tap a question — the answer appears below. Verified against the nickel-plated version catalogue of Conforti Oleodinamica.
Verified against
- Conforti nickel-plated version catalogue (NK — CD/DK/MD): ISO 6020/2, nickel 20 µm, 1200 h salt spray rating 10, no heavy metals or ammonia, mountings ME5/ME6/MS2/MP5, alternative to all-stainless, ISO 10100 test.
- Conforti Oleodinamica — corrosion protection in aggressive environments, ISO 10100 testing.
- Cylinder series catalogues and the technical library: TechHub.
The limitations of the nickel-plated version (no internal cushioning, limited set of mountings) and the suitability of sensors according to the IP rating are confirmed before ordering by the technical department of hydraulika.store.
