fLuID PoWer A breAch of rust - VOSS Automotive breAch of rust Voss zinc-nickel tube couplings with...
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iVT International Off-Highway 2012 when customers are often much more aware of corrosion problems than the vehicle manufacturer, an outdated attitude to preventing it can play havoc with an oem’s image – especially when it can even begin to show in the dealer’s yard Image is a necessity – as long as it is positive! Every company strives to build up a positive image – and, even more importantly, to maintain it. However, technical defects or visible blemishes can easily damage a good reputation. One major factor that can create a very bad impression is corrosion. In particular, unpainted vehicle components with electroplated coatings are often readily affected by corrosion. The components of vehicle hydraulics are particularly vulnerable – and in many cases this defect occurs even before the vehicle is sold, for example, when in the manufacturer’s or dealer’s yard. Most manufacturers are well aware of the weak points of their own products, and in the battle for market share they endeavour to eliminate them as quickly as possible. Yet while no manufacturer would ever sell a vehicle with defective paintwork, the corrosion of externally mounted parts is often neglected. The serious problem of tube couplings, hose connectors and tubing rusting after only a short spell of use or after regular operation during one single winter season is one of the best-known and most visible defects. Unfortunately, it is the end users who are more aware of this weakness than the manufacturers. The North American machinery manufacturing industry still relies on the traditional zinc-coating method of protecting tubing and other hydraulic components – yellow chromated or alternatively chromium(VI)-free with a silvery, metallic look. The protective layers are based solely on a zinc base coat that, in its optimum derivation, is provided with passivation and a sealing layer. But these surface coatings offer little protection against corrosion. Moreover, yellow chromation contains hexavalent chromium, which is classified as being toxic, mutagenic and carcinogenic. A safer solution A genuine alternative is a zinc-nickel treatment. This alternative surface contains an alloy of zinc and the high- valency element nickel. The nickel share is around 12-16%. Tube couplings with this resistant, chromium(VI)-free corrosion protection have already become standard in the European machinery manufacturing industry, and have now replaced most zinc coatings. The zinc-nickel surface was initially used in the automotive industry, before European Union directives on recycling later promoted this type of surface. To date, almost all hydraulic components are available with this finish. In combination with tubes that have an additional organic coating, it is now possible to implement a perfect corrosion-protection concept. In a salt spray test according to ISO 9227 and ASTM B117, the zinc-nickel surface achieved corrosion resistance for A breAch of rust Voss zinc-nickel tube couplings with Zistaplex tubes fLuID PoWer mArco schAWohL 135
Transcript of fLuID PoWer A breAch of rust - VOSS Automotive breAch of rust Voss zinc-nickel tube couplings with...
iVT International Off-Highway 2012
when customers are often much more aware of corrosion problems than the vehicle manufacturer, an outdated attitude to preventing it can play havoc with an oem’s image – especially when it can even begin to show in the dealer’s yard
Image is a necessity – as long as it is positive! Every company strives
to build up a positive image – and, even more importantly, to maintain it.
However, technical defects or visible blemishes can easily damage a good reputation. One major factor that can create a very bad impression is corrosion. In particular, unpainted vehicle components with electroplated coatings are often readily affected by corrosion. The components of vehicle hydraulics are particularly vulnerable – and in many cases this defect occurs even before the vehicle is sold, for example, when in the manufacturer’s or dealer’s yard.
Most manufacturers are well aware of the weak points of their own products, and in the battle for market share they endeavour to eliminate them as quickly as possible. Yet while no manufacturer would ever sell a vehicle with defective paintwork, the corrosion of externally mounted parts is often neglected.
The serious problem of tube couplings, hose connectors and tubing rusting after only a short spell of use or after regular operation during one single winter season is one of the best-known and most visible defects. Unfortunately, it is the end users who are more aware of this weakness than the manufacturers.
The North American machinery manufacturing industry still relies on the traditional zinc-coating method of protecting tubing and other hydraulic components – yellow chromated or alternatively chromium(VI)-free with a silvery, metallic look.
The protective layers are based solely on a zinc base coat that, in its optimum derivation, is provided with passivation and a sealing layer. But these surface coatings offer little protection against corrosion. Moreover, yellow chromation contains hexavalent chromium, which is classified as being toxic, mutagenic and carcinogenic.
A safer solutionA genuine alternative is a zinc-nickel treatment. This alternative surface contains an alloy of zinc and the high-valency element nickel. The nickel share is around 12-16%. Tube couplings with this resistant, chromium(VI)-free corrosion protection have already become standard in the European machinery manufacturing industry, and have now replaced most zinc coatings.
The zinc-nickel surface was initially used in the automotive industry, before European Union directives on recycling later promoted this type of surface.
To date, almost all hydraulic components are available with this finish. In combination with tubes that have an additional organic coating, it is now possible to implement a perfect corrosion-protection concept.
In a salt spray test according to ISO 9227 and ASTM B117, the zinc-nickel surface achieved corrosion resistance for
A breAch of rust
Voss zinc-nickel tube couplings with Zistaplex tubes
fLuID PoWermArco schAWohL
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fLuID PoWer
iVT International Off-Highway 2012
FROM TOP:FiguRe 1: White rust and red rust on a three-month-old used hydraulic connection with a zinc base layer coating as surface protection
FiguRe 2: White rust after three months in the field on a tube clamp part with a zinc base layer coat as the surface protection
FiguRe 3: Detail picture from the white rust and starting red rust of the tube connection. The surface protection on the tube is yellow chromated (A3C)
FiguRe 4: Detail from the white rust and initial red rust of the union nut. The surface protection on the union nut is zinc plus passivation and sealer
more than 720 hours before red rust occurred. White rust was observed after approximately 480 hours and then only appeared in the form of a slight grey discoloration. By contrast, yellow-chromated tube joints on a zinc base only achieved corrosion resistance for 72 hours before efflorescing white rust occurred. Red rust had already developed after 120 hours.
The rule of thumb derived from the empirical values of the salt spray tests is that if only the pure base coats are compared with each other, the corrosion resistance of zinc-nickel is approximately 10 times greater than that of pure zinc. Additionally, applied passivation and sealing further improve the corrosion resistance of protective layers.
Another advantage of the zinc-nickel surface is its resistance to mechanical stress. In practical applications, the surface layers of many components will have already been damaged for the first time during transport and handling; later the installation procedure will cause additional damage.
This is not such a problem with zinc-nickel surfaces because their surface is harder. Furthermore, the zinc-nickel surface does not have to fear technical-economic comparisons. It is no more expensive than other products available on the market.
the next stepThe next step in the evolution of corrosion protection is currently causing
a stir: the use of tube connectors with a zinc-nickel corrosion protection in combination with zinc-coated hydraulic tubes that have an additional organic coating. This combination offers the best possible corrosion protection.
Companies that have already shifted their production to using a combination of Voss Fluid tube couplings and Zistaplex tubes produced by Benteler Stahl/Rohr group include Goldhofer AG. The suppliers of the two components in this combination have thoroughly tested the combination of the dissimilar surfaces and can guarantee highest system safety and the best possible protection against corrosion. And because Goldhofer also uses other zinc-nickel coated hydraulic components such as tube clamps, hose
FiguRe 6: Result of the salt spray test
FiguRe 5: Comparison of coating structures
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iVT International Off-Highway 2012
CONTACT www.voss.de [email protected]
fLuID PoWer
fittings, sensing line couplings and ball valves, it currently boasts the most modern and comprehensive corrosion-protection system in the industry.
Voss Fluid was the first manufacturer to exclusively produce tube couplings with zinc-nickel surfaces. The couplings and flanges, coated in accordance with company-internal specifications, are resistant to all common hydraulic fluids. Furthermore, care is taken to ensure that the friction coefficients are identical to those of yellow chromation. This means that the same installation parameter values apply. The price of the products is in line with current market prices for tube couplings.
The correct choice of hydraulic coupling elements in combination with the right type of tubing has enabled unique, unprecedented protection against corrosion without having to use expensive stainless-steel components or perform complex masking and painting of the complete vehicle.
High-quality overall corrosion protection adds an additional unique feature to every product. This feature is an excellent selling point and can quite literally make a lasting impression on the end user. The zinc-nickel surface delays the formation of rust for a long period, while the technical functions of the components as well as the outward appearance of the complete product are maintained. iVT
Marco Schawohl is head of marketing at Voss Fluid GmbH
FiguRe 7 (LeFT): Comparison of the surfaces after salt spray test
FiguRe 8 (BeLOW): Structure of Zistaplex tubes
Tube conforming to EN 10305 / 1-4 Chromium (VI)-free
zinc coatingOrganic coating
Zinc-nickel base coating plus passivation and sealing
Zinc-base coating plus passivation and sealing
Yellow chromatising (A3C)
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Value added solutions
VOSS Fluid GmbHLüdenscheider Str. 52-54 - 51688 Wipperfürth - Germany - [email protected] - www.voss.de
VOSS Fluid – Solution for highest efficiency
Our competence enhances your product quality and reduces your costs considerably.
What are the features of a cost-effective hydraulic connection:
Permanently leakage free High assembly reliabilityOptimum system selection for each application Short assembly periodsNo reworkingHigh process accuracy
Bespokesolutions
Application of cutting edgeproduction technologies
Extensiveinternal test facility
Highestquality standards
Technical advice and training courses
Wideproduct range
11356_AZ_Englisch_Efficiency_IVT_Ausgabe.indd 1 01.09.11 14:51
