About Steel I Beam S4 X 7.7 X 10' Galv FAQ

A: Steel I Beam: I-beam ("I" cross-section) is a hot-rolled section steel with high flexural strength and light weight.
S4 X 7.7：
"S" stands for "Structural Steel I Beam" in the U.S. standard;
"4" means a cross-sectional height of approximately 4 inches (101.6mm);
"7.7" means a theoretical weight of approximately 7.7 pounds (approximately 3.5kg/ft) per foot of length.
10' Galv: 10 ft (3.048 m) in length with galvanized finish for corrosion protection.

A: Material: Usually ASTM A36 or A992 structural steel (US standard), equivalent to domestic Q235B or Q345B steel.
Mechanical Properties:
Tensile strength: ≥58 ksi (about 400MPa);
Yield strength: ≥36 ksi (about 250MPa);
Elongation: ≥20% (2 inches at 2 inches).

A: Galvanizing Standards: Typically meets ASTM A123 (hot-dip galvanizing) with a zinc layer thickness of ≥ 1.4mil (about 35μm).
Function: Protects the substrate through the oxidation of the zinc layer, and the atmospheric corrosion resistance is 5-10 times higher than that of bare steel, suitable for humid, open-air environments.

A: Structure:
beams, purlins, supporting structures (e.g., residential attics, balcony beams) for small buildings;
Floor support and wall skeleton of light steel structure.
Industrial Equipment:
equipment supports, platform frames, conveyor line tracks;
Small mechanical bases or load-bearing members.
Civilian Scene:
Garage door beams, storage shelves, stair handrails support;
Temporary construction or DIY works (e.g., scaffolding, workbench frames).

A: Lightweight design: Suitable for small to medium spans (≤10 feet) load-bearing, lighter than large-gauge steel sections, easy to transport and install.
Cost advantage: small cross-sectional size, low amount of material, lower price than heavy-duty I-beam.
Galvanized anti-corrosion: no additional coating is required, suitable for outdoor or humid environments, reducing maintenance costs.

A: Incise:
A grinding wheel cutter, plasma cutter or sawing machine can be used, and the zinc (such as zinc-rich paint) should be added to the incision after the galvanized layer is cut to avoid corrosion.
Weld:
It can be welded, but the galvanized layer in the welding area needs to be removed first (to avoid zinc vapor poisoning or weld porosity);
It is recommended to use E7018 electrode (low hydrogen type) to supplement the weld and surrounding area with zinc after welding.

A: Typical span recommendations:
When the simply supported beam span is ≤ 8 feet, the uniform load is about 1200 lb/ft (about 17.5kN/m);
For a 10-foot span, the uniform load is recommended ≤800 lb/ft (about 11.7kN/m).
Influencing factors:
The actual load bearing is affected by the load type (uniformly distributed/concentrated), the support method (simple/fixed), and the deflection limit (usually L/240) and needs to be confirmed by the structural calculation.

A: Bolted connection: Connected with high-strength bolts (such as A325) after drilling through the connecting plate (angle steel or steel plate), suitable for detachable scenes.
Welded connections: For permanent structures, the weld strength needs to be ≥ 80% of the base metal.
Embedded parts connection: The concrete structure can be welded and fixed by embedded steel plates.

A: Conventional environment: 20-30 years in a dry atmosphere;
Humid / Industrial environments: 10-15 years, coastal or high salt spray environments require additional protection (e.g. painting).

A: Minor damage: After grinding and rust removal, apply a zinc-rich primer with a zinc content of ≥95%, and then cover with paint.
Extensive breakage: Sandblasted and rust removed and then re-hot-dip galvanized or cold-galvanized (e.g. Zinc Rich Paint).

A: Yes, but only after surface treatment:
Wash the surface oil stain with solvent;
Sandblasting or sanding the galvanized layer to increase the roughness;
Spray zinc yellow primer or epoxy primer and coat it to improve adhesion.