Q235B Carbon Steel Flat Bar - 진전

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Carbon Steel · Flat Bar

Q235B Carbon Steel Flat Bar

Structural-grade mild steel flat bar with balanced strength, excellent weldability and superior formability — the all-round profile for fabrication, 프레임, supports and machinery parts.

기준: GB/T 700 Finish: Hot Rolled Custom Size Available
항복 강도
≥235 MPa
인장강도
370–500 MPa
Width Range
20–200 mm
Q235B Carbon Steel Flat Bar Bundles
01 · Product Overview

A versatile low-carbon structural profile

Q235B flat bar is a hot-rolled low-carbon steel section with a rectangular cross-section, produced to GB/T 700. Its controlled carbon content keeps the grade highly weldable while the manganese content provides dependable yield and tensile strength for everyday structural duty.

Widely used in steel structures, machine frames, 괄호, racks, railings and enclosure fabrication, Q235B flat bar offers the best cost-performance balance among ordinary structural steels — easy to cut, drill, bend and weld, available in a wide range of widths and thicknesses, and fully customizable in length.

02 · Key Features

Why choose Q235B flat bar

Guaranteed Yield Strength
Minimum yield of 235 MPa with tensile range 370–500 MPa, verified against GB/T 700 for reliable load-bearing performance.
Excellent Weldability
Low carbon content (max 0.20%) gives a low carbon equivalent, allowing smooth MIG, TIG and arc welding without preheating for most sections.
Superior Formability
Hot-rolled microstructure bends, punches and presses cleanly, ideal for brackets, channels, guards and cold-formed components.
Custom Cutting & Sizes
Available in 20–200 mm width, 3–25 mm thickness and any cut length from 1 m to 12 m — cut to your exact drawing.
Consistent Tolerance
Rolled to GB/T 702 dimensional tolerances with straight edges and square corners for accurate fit-up in assemblies.
Export-Grade Packaging
Steel-strapped bundles with woven fabric or waterproof wrap, palletized for sea, rail and road transport without damage.
03 · Chemical Composition

Chemical composition (wt%) — GB/T 700 Q235B

요소 탄소 (기음) 규소 (그리고) 망간 (망) 황 (에스) Phosphorus (피)
콘텐츠≤ 0.20≤ 0.35≤ 1.40≤ 0.045≤ 0.045

Note: single values are maximum limits per GB/T 700. Residual copper ≤ 0.30%. Heat analysis applies to ladle samples.

04 · Mechanical Properties

Mechanical properties (thickness ≤ 16 mm)

재산 Yield Strength ReH Tensile Strength Rm Elongation A Impact (20°C) 경도 (approx.)
235 MPa370 – 500 MPa 26% 27 J~ 121 HBW
Tensile strength — common structural grades comparison (MPa)
Q235B (this product)370 – 500
A36 (ASTM)400 – 550
S235JR (안에 10025)360 – 510
SS400 (그냥 G3101)400 – 510
05 · Physical Properties

Physical properties

밀도7.85 g/cm3
Melting point 1,510 °C
Modulus of elasticity200 평점
Poisson’s ratio0.30
Thermal conductivity (100°C)~ 50 W/(m·K)
Electrical resistivity (20°C)~ 0.17 µΩ·m
Coefficient of linear expansion~ 12×10⁻⁶ /°C
Surface finish밀 / black oxide
06 · Common Specifications

Common sizes & specifications

너비 (mm) 두께 (mm) 길이 Tolerance 가장자리
20, 25, 30, 403, 4, 5, 66 m standardGB/T 702Fully rounded / square
50, 60, 80, 1006, 8, 10, 126 m / custom±0.5 mm (두께)Straight, burr-free
120, 150, 20012, 16, 20, 25Up to 12 mGB/T 702Straight, deburred

Sizes beyond this table, customized lengths and non-standard dimensions are available on request.

07 · Applications

Where Q235B flat bar is used

  • Steel structures, frames and light trusses
  • Machine frames, bases and fabricated parts
  • Racks, shelves, supports and brackets
  • Bridges, railings, guards and handrails
  • Electrical cabinets and distribution enclosures
  • Agricultural machinery and transport equipment
Q235B Flat Bar Warehouse Stock
08 · Processing & 포장

Processing services & export packaging

Processing
Cutting to length
Drilling & punching holes
벤딩 & forming
Shot blasting & derusting
Painting (primer / epoxy)
Hot-dip galvanizing
포장
Steel strap bundles, 2–3 t per bundle
Woven fabric or water-proof wrap
Wooden pallet / crate for sea freight
Labels with grade, size & batch no.
Mill test certificate (MTC) supplied
3rd-party inspection acceptable
Need Q235B flat bar in custom sizes?

Send us your width, thickness and length requirements — we reply within 24 hours with a competitive quote, stock availability and shipping options.

Request a Quote

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