Coating Service for Hydraulic Cylinders

Montanhydraulik’s solutions for excellent corrosion protection

We take corrosion protection seriously. At Montanhydraulik we work permanently to offer our customers advanced and high-quality corrosion protection solutions. The basis for this is the Montanhydraulik Coating Centre. Coatings are used to protect piston rods from corrosion and wear.

Ensuring the quality of our products is the basis of our daily work and the goal for our coating centre. Through our own certified quality assurance we are able to regularly check the quality of our coatings and can guarantee that our coatings are of best quality. This is reflected in the reliability of our products. Thanks to our in-house electroplating facility and a network of competent sub-suppliers, we can always deliver on time. This reflects a high delivery performance for the benefit of our customers.

We offer many different types of metal coatings:

The graphic provides an overview of the coating portfolio offered by the Montanhydraulik Group for piston rods of hydraulic cylinders. A total of 20 different coating options are presented, divided into four main categories: electroplating, thermal spraying, cladding (laser cladding), and special solutions. In the electroplating category, the coatings are based on hard chrome or nickel-chrome combinations. Examples include MH-1-HARD CHROME and MH-X-NICKEL-CHROME. The thermal spraying group comprises both plasma-sprayed ceramic coatings and hard carbide coatings. This group includes six different options, such as MH-X-TREME-03 and MH-lm4-CHROME-CARBIDE. The cladding category features three coatings applied by laser cladding: MH-55-STAINLESS STEEL, MH-X-INCODUR, and MH-lm4-INCOTEC. The portfolio is rounded off by three special solutions developed for specific requirements: MH-2-NICARBOX, MH-4-BLACK ARMOR, and MH-X-PROTECT COVER. All coatings shown undergo thorough quality control before being delivered to the customer.

High-performance coatings for maximum protection

In addition to proven electrodeposited coatings based on chromium or nickel-chromium, Montanhydraulik also offers thermally sprayed coatings. It does not matter whether a plasma sprayed ceramic is needed to protect the piston rod in offshore applications or a hard carbide coating for highest wear requirements. Montanhydraulik offers the best technology and innovative solutions.

We have classified our coatings according to their ability to withstand the conditions of the different corrosivity categories of the international standards DIN EN ISO 9223 and DIN EN ISO 12944-2 in order to offer our customers reliable assistance in selecting the suitable coating system for your piston rod. The following table compares the Montanhydraulik coatings with regard to their hardness (indicator for wear resistance according to DIN EN ISO 6507) and their corrosion resistance in the neutral salt spray test (DIN EN ISO 9227):

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The graphic compares the coating options offered by the Montanhydraulik Group with regard to their hardness – an indicator of wear resistance in accordance with DIN EN ISO 6507 – and their corrosion resistance based on the salt spray test according to DIN EN ISO 9227. The information is presented in a matrix, where the Y-axis shows the hardness of the coatings measured in Vickers Hardness (HV), with a scale ranging from 0 to 1,600 HV. The X-axis represents corrosion resistance in hours of exposure in the Neutral Salt Spray test (NSS/h), ranging from 0 to 4,320 NSS/h.

Above the coordinate system, the graphic also includes a classification based on corrosivity categories according to international standards DIN EN ISO 9223 and DIN EN ISO 12944-2. These start at category C1 and progress through C2, C3, C4 and C5 (around 720 NSS/h), up to the more demanding categories CX (approx. 1,000 NSS/h) and lm4 (approx. 4,200 NSS/h).

Within the matrix, all 20 coating options of the Montanhydraulik Group are shown. Hard chrome coatings – such as MH-1-HARD CHROME and MH-2-HARD CHROME – offer a medium hardness level of approximately 850 to 1,100 HV. Their corrosion resistance increases with product number but remains relatively low, maxing out around 360 NSS/h. As a result, these coatings provide only limited corrosion protection. Nickel-chrome coatings offer similar hardness values but significantly better corrosion resistance, reaching up to 1,000 NSS/h, as seen with MH-X-NICKEL CHROME.

The highest hardness among all coatings is achieved by MH-lm4-TUNGSTEN CARBIDE, with values between 1,500 and 1,600 HV. This coating also provides the strongest corrosion resistance, up to 4,200 NSS/h, placing it in the top right of the matrix. Other coatings, such as MH-lm4-CERAMICS and MH-lm4-INCOTEC, offer comparable corrosion protection but are softer in comparison.

Overall, the graphic gives a clear overview of the performance characteristics of each coating in terms of wear resistance and corrosion protection, helping users to identify the most suitable solution for their specific application needs.

Corrosivity categories according to DIN EN ISO 9223 and 12944-2

VERY LOW CORROSIVITY (C1)

Interior: heated buildings with clean atmospheres, for example offices, schools, shops, hotels

Exterior: dry or cold climate, for example certain desert areas, arctic/Antarctic centre

Air:

SO₂-concentration: insignificant

Cl^--concentration: insignificant

Relative humidity: low

Contamination: insignificant

LOW CORROSIVITY (C2)

Interior: unheated climate, for example warehouses, sports halls

Exterior: for example rural areas, small towns, deserts, subarctic regions

Air:

SO₂-concentration: < 5 µg/m³

Cl^--concentration: insignificant

Relative humidity: rare condensation/ short humidification

Contamination: low

MEDIUM CORROSIVITY (C3)

Interior: for example plants for food processing, laundries, breweries

Exterior: temperate, subtropical and tropical climate, for example urban/industrial atmosphere with moderate sulphur dioxide pollution; coastal areas with low salt concentration

Air:

SO₂-concentration: 5 to 30 µg/m³

Cl^--concentration: low

Relative humidity: high/occasional condensation

Contamination: low to moderate (production)

HIGH CORROSIVITY (C4)

Interior: for example industrial/chemical plants, coastal shipyards /boat harbours

Exterior: temperate, subtropical and tropical climate, for example urban /industrial areas with air pollution and pollution by de-icing salts and coastal areas, not in the area of salt water spray mist

Air:

SO₂-concentration: 30 to 90 µg/m³

Cl^--concentration: significant

Relative humidity: frequent condensation

Contamination: moderate to high (production)

VERY HIGH CORROSIVITY (C5)

Interior: for example mines, cavities for industrial purposes, non-ventilated halls in subtropical and tropical climate zones

Exterior: temperate or subtropical climate, for example industrial areas with high air humidity and aggressive atmosphere, coastal atmosphere with high salinity/protected areas on the coastline

Air:

SO₂-concentration: 90 to 250 µg/m³

Cl^--concentration: significant / high

Relative humidity: very frequent condensation

Contamination: very high/ severe (production)

EXTREME CORROSIVITY (CX)

Interior: for example non-ventilated halls in humid tropical climate zones with air pollutants, e.g. chlorides and corrosion-promoting dust

Exterior: subtropical and tropical climate, offshore, for example areas with intensive industrial use and extreme air pollution, coastal and offshore areas with high salinity, accidental contact with salt spray mist

Air:

SO₂-concentration: > 250 µg/m³

Cl^--concentration: high/severe

Relative humidity: extrem. high/nearly const. condensation

Contamination: very high/ severe (production)

Corrosivity categories for environments in soil and water in accordance with DIN EN ISO 12944-2

Im1

Environment: Fresh water

Field of application: River constructions, hydroelectric power stations

Im2

Environment: Sea water, brackish water

Field of application: Steel structures in contact with water without cathodic corrosion protection, for example harbour area with steel structures such as lock gates, locks or piers