About Galvanized Angle Steel L50x50x5mm FAQ

A: Size:

Equilateral angle steel, side length 50mm×50mm, thickness 5mm, length is usually 6 meters (other lengths can also be customized, such as 3 meters, 12 meters, etc.).
Material:

The main body is Q235 or Q355 low carbon steel, and the surface is hot-dip galvanized (the thickness of the zinc layer ≥ 85μm, which needs to refer to the national standard GB/T 13912).
Theoretical weight:

approx. 3.77kg/m (calculated as (side length ×2 - thickness)× thickness ×0.00785, i.e. (50×2 - 5)×5×0.00785≈3.77kg/m).

A: Hot-dip galvanizing features:
● The zinc layer forms a metallurgical bond with steel, with strong adhesion and excellent corrosion resistance, and can be used in outdoor environments for more than 20 years.
● The thickness of the zinc layer is uniform, the surface is gray-white, and there are slight zinc flowers, which is suitable for long-term exposure to moisture, acid and alkali and other environments.
Cold galvanizing (electro-galvanizing) differences:
The zinc layer is thin (about 5-15μm), has weak adhesion, and poor corrosion resistance, making it suitable for indoor or mild corrosion scenarios.
The surface is smooth and shiny, the color is lighter, and the price is lower than that of hot-dip galvanizing.
Identification method: observe the surface gloss (hot-dip galvanized gray, cold-dip galvanized bright), measure the thickness of the zinc layer (hot-dip galvanized is thicker), or ask the supplier to provide a test report.

A: Building structures: as steel supports, frame connectors (e.g. scaffolding, roof trusses, wall keels), or as embedded parts in concrete structures.
Equipment manufacturing: production of mechanical supports, equipment bases, storage shelves (such as industrial shelf beams, column connectors).
Municipal engineering: street lamp pole base, bridge guardrail support, outdoor billboard frame.
Agriculture and breeding: greenhouse skeleton, fence support, breeding equipment fixings.

A: Incise: 

A grinding wheel cutter, plasma cutter or sawing machine can be used, and the cut burr needs to be cleaned after cutting to avoid scratching the zinc layer.
Weld: 

● Before welding, the zinc layer (about 50mm range) of the weld part should be polished off to prevent the zinc layer from volatilizing and generating porosity when heated, which will affect the strength of the weld.
● Arc welding (e.g. E43 electrode) is recommended, and the weld and its surroundings need to be re-treated with anti-corrosion (e.g., zinc powder paint) after welding.
Drill: 

High-speed steel drill bits or alloy drill bits can be used, and low speed feed is recommended when drilling to avoid overheating and wear of the drill bit.

A: Conventional environment:

The hot-dip galvanized layer has excellent corrosion resistance in a neutral atmospheric environment, and can be used for more than 50 years in a suburban environment and about 20-30 years in an urban environment.
Special Environment:
Seaside: Seawater mist contains chloride ions, which will accelerate the corrosion of the zinc layer, so it is recommended to choose a higher zinc layer thickness (such as more than 100μm) or additional spraying of anti-corrosion coatings.
Chemical plants:

If exposed to strong acids and alkalis (e.g., sulfuric acid, sodium hydroxide), the concentration of the medium needs to be assessed, and stainless steel or higher grade anti-corrosion treatment (e.g., galvanized epoxy coating) may be required.

A: Visual inspection:

the zinc layer on the surface should be uniform, no leakage plating, no bubbles or peeling, and no obvious deformation of the corners and corners.
Dimensional measurement:

Use calipers to measure whether the edge length and thickness meet 50×50×5mm, and the length error does not exceed ±5mm (refer to GB/T 706 standard).
Zinc layer inspection:

Measure the thickness of the zinc layer (hot-dip galvanized ≥ 85μm) with a magnetic thickness gauge, or ask the supplier to provide proof of material, galvanized test report (e.g. ISO 1461 certification).
Mechanical properties:

If high-strength scenarios are required, tensile strength (Q235≥235MPa, Q355≥355MPa) and bending properties can be sampled for testing.

A: Strength difference:

50x50x5mm has a larger cross-sectional area and stronger bearing capacity, which is suitable for scenarios with large spans and high loads (such as large brackets); L40x40x4mm is more suitable for light-duty structures (e.g. small shelves).
Weight and cost:

50x50x5mm weighs about 3.77kg per meter, which is heavier than L40x40x4mm (about 2.42kg/m), and the material cost is higher, so it needs to be selected according to the actual load.

A: Transportation:

Avoid deformation caused by stacking too high, and separate with straw rope or pallet to prevent the zinc layer from rubbing off.
Storage:

Store in a dry and ventilated place to avoid rainwater soaking; If it is stored for a long time, the surface can be covered with a moisture-proof cloth to prevent the zinc layer from oxidizing and whitening (producing "white rust", which does not affect the internal corrosion, but affects the appearance).

A: Length customization:

Most suppliers can provide cut-to-length (e.g. 2 meters, 4 meters), but the minimum order quantity (usually 5-10 tons) needs to be reached, and the customization cycle is about 3-7 days.
Secondary processing:

punching, bending, welding and forming can be carried out as needed (such as processing into right-angle brackets), but it is necessary to confirm the processing technology and cost with the manufacturer in advance.

A: ● Steel standards: GB/T 700 (carbon structural steel), GB/T 1591 (low-alloy high-strength structural steel).
● Galvanizing standard: GB/T 13912 (metal overlay, hot-dip galvanized layer for steel parts), ISO 1461 (international hot-dip galvanizing standard).
● Angle steel size standard: GB/T 706 (hot-rolled section size, shape, weight and allowable deviation).