Chains for hot dip galvanizers, hardening shops and pickling plants
Because of the special environmental conditions (zinc baths up to 475°C,
hydrochloric or sulphuric acid baths with a concentration of 15% at approx.
30°C=86°F) only chains in special qualities and with reduced lifting
capacities can be used in hot dip galvanizing, hardening shops and pickling
plants. If other chains are used there is a danger of hydrogen embrittlement.
The following can be used:
- Chains acc. to DIN 32891 grade 2 - stress-relieved annealed
- Armco chains grade 2
- Chains acc. to EN 818-6 - 4 grade 4, with increased tempering temperature
- Kettenfabrik Unnas stainless sling chain system grade 5
- DIN 32891 Quality Class 2 chains must be stress-relieved annealed for use
in hot dip galvanizing.This means heat treatment at a temperature clearly
above 1000°C. Here the steel's carbon content is reduced and the alloy
elements from the enriched zones (segregations) are evenly distributed. This
reduces the danger of stress corrosion.
- Armco has a carbon content acc. to DIN of less than 0,03% usually less
than 0,01%.
This reduces the danger of intercrystalline corrosion as well.
- Chains in accordance with EN 818-6 - 4 are heat-treated at min. 450°C,
i.e. chains may only be used at temperatures up to 400°C. Because temperatures
of up to 475°C are usually reached in galvanizing baths, chains for this
application are heat-treated at a temperature higher than 600°C leading
to a ferritic grain size of 7
or better. However, this also means a reduction of the working load limits
as well.
- The Kettenfabrik Unna stainless sling chain system is manufactured from
corrosion-resistant stainless material in accordance with DIN 17440.
The safety provisions (ZH 1/323) prescribe reduced carrying capacities for
all chains in order to take account of the aggressive ambient conditions. The
following lifting capacities apply for single strands in Germany (for other
countries please contact us)
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Measurement
in mm
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Grade 2 DIN 32891 + Armco
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Working load limit grade 4 EN 818-3
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NBKS grade 5
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6 x 18
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k.A.
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k.A.
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300
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8 x 24
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k.A.
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500
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530
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10 x 30
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320
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800
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850
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13 x 39
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500
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1.300
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1.400
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16 x 48
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800
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2.000
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2.200
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Chains for galvanization companies produced of pure iron
Pure iron shows higher resistance against intercrystalline corrosion due to its high purity (carbon ≤0,030%). Chains made from pure iron are suitable for the use in galvanizing shops. Sling chains made of pure iron are a good alternative to chains of unalloyed steels, with reference to economical and safety reasons. Armco chains have a 2,5-3 times higher life time than chains grade 2 or chains EN 818 grade 4.
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