Hot Rolled Flat Steel is a long rectangular-section steel bar with smooth edges, characterized by high dimensional accuracy, excellent surface finish, stable mechanical properties, and ease of cutting, welding, and machining. We offer both hot-rolled and cold-drawn/cold-rolled flat bars, widely used in machinery, automotive, construction, power equipment, rail transit, shipbuilding, energy projects, and hardware manufacturing. Manufactured to international standards, our products meet diverse requirements for strength, toughness, and corrosion resistance, making them essential materials in industrial and engineering applications.
Key Features
Standards:
Chinese Standards:
GB/T 704-2016 (Hot-Rolled Flat Steel)
GB/T 702-2017 (Dimensions, Shape, Weight and Tolerances for Hot-Rolled Steel Bars)
GB/T 700-2006 (Carbon Structural Steels)
GB/T 1591-2018 (High-Strength Low-Alloy Steels)
International Standards:
JIS G 3192 (Japanese Flat Steel)
ASTM A36/A36M (Carbon Structural Steel)
ASTM A572/A572M (High-Strength Low-Alloy Steel)
EN 10025-2 (Structural Steels: S235, S275, S355)
DIN 1017 (German Flat Steel Standard)
Industry Codes:
GB 50017 (Code for Design of Steel Structures)
JB/T 5000.8 (General Technical Conditions for Heavy Machinery – Forgings)
Materials:
Carbon Structural Steels: Q235A/B/C (General purpose), Q355B (High strength, replaces Q345B)
Quality Carbon Steels: 20#, 45# (for shafts, pins, connectors, heat-treatable)
High-Strength Low-Alloy Steels: Q390B, Q420B, Q460C (for heavy machinery, bridges, towers)
Stainless Steels: 304/304L, 316/316L, 2205 Duplex (for chemical, food, marine environments)
Marine & Offshore Steels: AH36, DH36, EH36 (impact tested at -40°C)
Tool & Spring Steels (Cold-Drawn): 65Mn, T8, T10 (for springs, blades, dies)
Dimensions:
Width: 10mm – 300mm
Thickness: 3mm – 60mm
Length: Hot-Rolled: 6m, 9m, 12m standard; up to 18m
Cold-Drawn: 1m – 6m (custom lengths available)
Common Sizes: 20×5, 40×4, 50×6, 80×8, 100×10, 150×12, 200×20, 300×30 (mm)
Custom Fabrication: Chamfering, pre-drilling, bending, slitting, polishing available
Applications:
Machinery: Shafts, brackets, flange blanks, gear blanks, spring leaves
Construction: Stair treads, railing posts, curtain wall frames, embeds, stiffeners
Power & Energy: Transformer clamps, busbar supports, PV frames, wind tower flange parts
Marine & Shipbuilding: Hull ribs, deck stiffeners, ladder treads, pipe clamps
Rail Transit: Rail fasteners, bogie parts, body reinforcements
Automotive: Chassis beams, suspension parts, bumper reinforcements
Hardware: Hinges, lock components, tool handles, agricultural parts
Chemical & Food Equipment: Stainless flat bars for agitators, conveyor supports
Certifications & Approvals:
Classification Society Certifications:
CCS, ABS, DNV, LR, BV, NK
Provide type approval, MTC 3.1/3.2, factory inspection reports, and CoC
Owner & Engineering Company Approvals:
ISO 9001, ISO 14001, ISO 45001
PED 2014/68/EU (for pressure equipment components)
NORSOK M-650 / M-601
Approved by CSCEC, CCCC, Sinopec, CNOOC, Shell, ExxonMobil, BP, Total, Chevron, Woodside, etc.
Common Customer Questions (Q&A Format)
Q: What is the difference between flat steel and steel strips?
A: Flat steel is standard-sized with high precision; steel strips are cut from plates, more flexible in size but lower in accuracy and higher in cost.
Q: What is the difference between Q235B and Q355B?
A: Q235B has yield strength ≥235MPa for general use; Q355B ≥355MPa for heavy-duty or dynamic load applications.
Q: Do you offer custom sizes?
A: Yes, we can customize width, thickness, length, and fabrication (chamfering, holes, bending, slitting) per drawings.
Q: Do you provide corrosion protection?
A: Yes, options include hot-dip galvanizing (ISO 1461), epoxy coating, Dacromet, and stainless cladding.
Q: How is weldability?
A: Q235B and Q355B have excellent weldability using GMAW, SMAW, etc. Preheating required for thick sections.
Q: Do you provide Material Test Certificates (MTC)?
A: Yes, MTC 3.1 or 3.2 provided per batch with heat number, chemistry, tensile/impact data, and compliance.
Q: What is the maximum single length?
A: Hot-rolled: up to 18m; cold-drawn: up to 6m; longer pieces can be segmented.
Q: Are your flat bars suitable for low-temperature service?
A: Yes, we supply Q355N, S355NL, or class-approved AH36/DH36/EH36 steels for -40°C applications.
Q: How is dimensional accuracy ensured?
A: Hot-rolled bars comply with GB/T 704; cold-drawn bars use precision rolling, thickness tolerance ≤±0.2mm, width ≤±1mm.
Q: What is the lead time?
A: Standard sizes: 7–15 days; custom fabrication: 20–45 days, depending on complexity and material availability.
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