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Galvanized Carbon Steel Flat Bar
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Galvanized & Carbon Steel Flat Bar

Hot-rolled flat bar with a rectangular section, used for base plates, brackets, grating, gates and railings, earthing strip, machinery parts and structural connections. Supplied black, pickled or hot-dip galvanized.

ProductHot-rolled flat steel bar – black or galvanized
Width10 – 500 mm
Thickness1.5 – 30 mm
Length6 – 12 m or to order
GradesQ195, Q215, Q235B, Q345B, Q420, S235JR, S355JR, SS400, SM400A/B, ASTM A36
StandardsGB/T 702, EN 10058, ASTM A6/A36, JIS G3194
ToleranceThickness ±0.02 mm (cold finished) / to standard; width ±2 mm
SurfaceBlack, pickled & oiled, hot-dip galvanized (ISO 1461)
ProcessingCutting, punching, drilling, bending
PackingTied with steel strips, wrapped in waterproof paper
DeliveryWithin 30 days after deposit
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Typical applications

  • Construction: base plates, gusset and connection plates, stair stringers, lintels and embedded plates.
  • Steel grating: bearing bars of 25×3, 30×3, 32×5 and 40×5 mm.
  • Gates, fences and railings: 20×3 to 50×6 mm, often hot-dip galvanized.
  • Earthing and lightning protection: hot-dip galvanized strip, 25×3, 25×4 and 40×4 mm.
  • Machinery and trailers: brackets, clamps, leaf-spring blanks and wear strips.

Grades

GradeStandardMin. yield (MPa)Equivalent
Q235BGB/T 700235S235JR, SS400, A36 (approx.)
Q345B / Q355BGB/T 1591345 / 355S355JR
S235JR / S355JREN 10025-2235 / 355—
ASTM A36ASTM A36250Q235B, SS400
SS400JIS G3101245Q235B

Weight table (kg per metre)

Width × thickness (mm)kg/m
25 × 30.59
25 × 50.98
30 × 30.71
40 × 41.26
50 × 51.96
50 × 103.93
75 × 84.71
100 × 107.85
150 × 1214.13
200 × 2031.40

Formula: width (mm) × thickness (mm) × 0.00785 = kg per metre.

Galvanizing

Hot-dip galvanized flat bar is dipped after cutting, so the edges are protected too. Coating thickness follows ISO 1461 (typically at least 70 µm on 3–6 mm steel), which is what earthing and outdoor-railing specifications usually require. Flat bar can be punched, drilled or bent before galvanizing, so fabricated parts arrive ready to install.

Packing and delivery

Bars are bundled and tied with steel strips, then wrapped in waterproof paper. Galvanized bars are separated with spacers so white rust does not form in transit. Lengths are 6 m (for 20ft containers) or 12 m. Delivery is within 30 days after the deposit, from Tianjin or Qingdao.

Frequently asked questions

How do I calculate the weight of flat bar?

Multiply width (mm) by thickness (mm) by 0.00785 to get kg per metre. For example, 50×5 mm weighs 1.96 kg/m, so a 6 m bar weighs about 11.8 kg.

What size of galvanized flat bar is used for earthing?

25×3 mm and 25×4 mm are the most common for earthing conductors, and 40×4 mm or 50×6 mm for main earth rings. Follow your electrical consultant's specification.

Is Q235B the same as ASTM A36?

They are similar mild steels and often interchangeable for general fabrication. A36 has a slightly higher minimum yield (250 against 235 MPa), so check with the designer before substituting on structural work.

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