This article describes the main applications of galvanised steel and how the zinc coating protects the steel. Mechanism: hot-dip galvanising applies a zinc layer that corrodes preferentially (sacrificial protection) and seals the steel surface - galvanised steel does not "never rust", but the zinc gives a long, predictable protection period; cut edges and scratches are still protected locally by the adjacent zinc.
Applications: (1) construction - roofing and cladding, ridges and valleys, steel frames, balconies, purlins and girts; (2) manufacturing - small parts, tanks and containers for non-corrosive materials; (3) automotive - body panels and underbody parts (modern cars use alloy-coated grades such as Galvannealed or zinc-aluminium); (4) appliances - washing machines, refrigerators, HVAC cabinets; (5) agriculture and energy - fencing, silos, transmission towers, solar mounting structures. Coating weight (e.g. Z100–Z275 per EN 10346) is specified in g/m² and chosen by environment and required service life; governing standards include EN 10346, ASTM A653/A924 and GB/T 2518.
Products Description
Galvanised steel is carbon steel with a protective zinc coating applied by hot-dip galvanising (or electrolytic plating). The zinc protects the steel in two ways: it seals the surface from moisture and oxygen, and it corrodes preferentially (sacrificial/cathodic protection) - so scratches and cut edges remain protected by the adjacent zinc. It does not "never rust", but it offers a long, predictable protection period.
1. Construction
Roofing and cladding sheets, ridges and valleys - the largest single use;
Steel frames, balconies, purlins, wall girts and other outdoor structural elements;
Fencing, guardrails and temporary structures.
2. Manufacturing
Industrial parts and components produced by stamping, roll-forming and profiling;
Tanks and containers for storing non-corrosive materials;
Ducting, cable trays and electrical enclosures.
3. Automotive
Body panels and underbody components use zinc-coated steel (including alloy-coated grades such as galvannealed and zinc-aluminium) for corrosion resistance in road-salt environments.
4. Appliances and Other Industries
Home appliances - washing machines, refrigerators, dishwashers, HVAC cabinets;
Agriculture - farm buildings, silos, fencing;
Energy - transmission towers, solar mounting frames, cable management.
5. Specification Notes
Coating weight (e.g. Z100–Z275, g/m² both sides) is selected by environment and required life per EN 10346, ASTM A653/A924 or GB/T 2518;
Confirm base grade (e.g. DX51D, S250GD, SGCC), coating type (zinc, zinc-aluminium, galvannealed) and surface finish (spangle, zero-spangle) with the supplier;
Request the mill certificate with coating weight and mechanical data.
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GALVANIZED STEEL COIL |
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Standard |
ISO,JIS,AS EN,ASTM |
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Grade |
Q195 Q235 Q345 |
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SGCC SGCH SGC340 SGC400 SGC440 SGC490 SGC570 |
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SGHC SGH340 SGH400 SGH440 SGH490 SGH540 |
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DX51D DX52D DX53D DX54D DX55D DX56D DX57D |
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S220GD S250GD S280GD S320GD S350GD S400GD S500GD S550GD |
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SS230 SS250 SS275 |
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