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Galvanized Steel in Agriculture


Galvanized Steel in Agriculture

Why Galvanize? Great value for money Long life Toughness Protects externally and internally Hygienic for use around animals

Steel is one of the most commonly used materials in agriculture. It is strong, versatile and economic. Consequently it is used for a variety of different applications from fences and gates to building frames, feeding barriers and appliances. However, steel must be protected or it will rust, and that costs the agriculture industry many millions of pounds every year.

The method you choose to protect your steelwork today could have a major influence on the time and money that must be spent tomorrow. What is needed is an economic, long lasting method of steel protection. It has to be tough, safe to use with animals and crops and needs little maintenance.

The Coating

The Cost

Agricultural steelwork has been protected by hot dip galvanizing for more than one hundred years. In the past it was mainly small objects such as buckets, watering cans and feeding troughs that were galvanized – and they usually lasted until they were worn out. Today, most steel products can receive the same level of protection, not just building frames and farm gates but all fencing, penstock equipment and appliances.

The hot dip galvanizing process consists of dipping the steelwork, after it has been chemically cleaned, in a bath of molten zinc. The zinc reacts with the steel to form alloys that are metallurgically bonded to it. Upon withdrawal from the galvanizing bath, a layer of pure zinc covers the alloy layers. The coating has unique resistance to damage from, for example, farm vehicles. The outer layer of pure zinc cushions impact, while the zinc-iron layers beneath, which are harder than steel, provide abrasion resistance.

Schematic section through a typical hot dip galvanized coating.

Hot dip galvanizing meets all these needs.

Low initial cost and long, maintenance-free life mean hot dip galvanizing offers the best possible return on investments in steel structures and agricultural equipment.

The graph below shows that, for all but the heaviest steel sections, hot dip galvanizing is very competitive with a good paint system. Painting is very labour intensive compared with galvanizing which is a highly mechanised, closely controlled factory process.

Competitive initial cost: Contrary to popular belief, galvanizing is not an expensive corrosion protection system for steel.

Comparison between initial costs.

140 140 4 coat paint

120 120 3 coat paint

relative cost

relative cost

100 100 80 80 60 60

hot dip galvanize 40 40 20 20

pure zinc Pure Zinc

6% Fe 6% Fe

10% Fe 10% Fe

base steel Base Steel

2

2

3

3

5

5

6

6

8

8

10

10

steel thickness (mm)

steel thickness (mm)

14

14

19

19

25

25


Long Life

Sustainability

A standard hot dip galvanized coating on fabricated steelwork, i.e. building frame, gate or appliance, give a typical life without maintenance of 50+ years in a rural environment. A paint coating could need remedial work three or four times before the galvanizing needs any attention. This is both time consuming and expensive, especially when it involves the use of outside contractors and scaffolding, or the structure is on outlying land.

In the case of a barn or animal shed it could be very inconvenient to re-site livestock so that maintenance could be carried out. It has been estimated that with paint, for every pound spent on the initial investment, another pound is spent on repairs and maintenance. Specifying hot dip galvanized steel will reduce maintenance bills and the time involved in maintenance.

Microsection of hot dip galvanized coating showing variataions in hardness through the coating. The zinc-iron alloys are harder than the base steel.

Hardness, HV Values > hardness, HV values 50 50

Zn Zn

Zn Zn + + Fe Fe

Fe Fe

100 100

150 150

>

200 200

250 250

All the above benefits are achieved by galvanizing your steel. But, you can get another major plus, completely free - a more sustainable steel structure. Recent studies have shown that galvanizing is a far more sustainable solution for corrosion protection when compared to other systems. For further information www.sustainable-galvanizing.com


Other benefits of hot dip galvanizing in agriculture.

Toughness and abrasion resistance Hot dip galvanizing produces a tough, durable and permanently bonded coating which is better than many other systems in protecting steel from damage, for instance, from tractors or machinery. What’s more, any bare steel exposed by scratches or drilled holes is protected by the surrounding zinc.

Availability

Specifications

Hot dip galvanizing facilities are widely available so your suppliers should be able to offer hot dip galvanized products. It is recommended that a galvanizer is used which is a member of Galvanizers Association.

Specifying materials and products can be a complex and confusing process. Specifying galvanizing however is very staightforward. To ensure you get the correct coating for your steel follow these simple steps:

Visit www.galvanizing.org.uk or contact GA +44(0)121 355 8838

Reliability

Environmental performance

Complete coverage, inside and out is a unique feature of hot dip galvanized coatings.

Left alone outside, hot dip galvanizing will protect steel from the weather for many decades.

Hygiene

It will protect steel from other substances found on farms such as diesel oil and petrol.

The abrasion and corrosion resistance of hot dip galvanized steel provides an easy to clean and hygienic surface.

However, galvanized steel can be attacked by prolonged exposure to acidic materials such as slurry and manure. If this is likely, a coat of bitumen paint should be applied to the galvanized steelwork. Short term exposure, as in slurry pumps, is not normally a problem providing that the steelwork is rinsed off after use and allowed to dry.

Reduced labour Particularly with building frames, once the hot dip galvanized steel is erected cladding can begin immediately. This eliminates time consuming on-site painting.

Galvanizing offers Great value Long life Tough coating, takes knocks and bangs of everyday farming Protects all your steel inside and out

Wren’s Court, 56 Victoria Road Sutton Coldfield, West Midlands B72 1SY Telephone: +44 (0)121 355 8838 Fax: +44 (0)121 355 8727 e-mail: ga@hdg.org.uk www.galvanizing.org.uk

1

In the UK hot dip galvanized agricultural steel building frames should be supplied to BS 5502: Code of Practice for the Design of Buildings and Structures in Agriculture. In Ireland they should conform to the Farm Development Service Specification S101.

2

Make reference to Part 21 of BS 5502 where specification of hot dip galvanizing is cited.

3

This will ensure that EN ISO 1461 is also referenced as the main standard for the coating of iron and steel articles.

It is also advisable to paint galvanized steelwork with bitumen paint if it is going to be immersed continuously in water.

Galvanizers Association has provided authoritative information and advice on hot dip galvanizing to users and potential users since it was first established in 1949. Further information and advice on the use of hot dip galvanizing in agriculture is available from the Association.


Galvanized Steel in Agriculture