≥ 355 MPa
Nominal Q355 grade minimum yield-strength reference for the relevant thickness group. Thin-coil testing provisions require product-standard review.
Global Steel Supply & Processing
Q355B | GB/T 1591-2018 | GB/T 3274-2017
MILL SPECIFICATION / COIL SIZES / EXPORT RFQ
Specify Q355B hot rolled coil by thickness, width, coil net weight and mill-edge or slit-edge condition. Our team coordinates GB/T 1591 material verification, order-specific test requirements and bulk quotations for steel service centers and industrial buyers.
Explore coil specifications ↓Order the correct grade and supply condition with a complete coil schedule. Verify the thickness, mechanical test basis, usable width and downstream handling limits before release.
| Steel grade | Q355B — high-strength low-alloy structural steel, quality grade B |
| Grade / chemistry / mechanics | GB/T 1591-2018 |
| Hot-rolled coil product standard | GB/T 3274-2017, within its applicable product scope |
| Dimensions, shape & tolerances | GB/T 709-2019, subject to ordered width and strip form |
| Product form | Hot rolled wide coil, slit coil or cut-to-length sheet by agreement |
| Thickness for enquiry | Illustrative purchasing range 2.0–12.0 mm; exact availability verified by quotation |
| Width for enquiry | 1000 / 1250 / 1500 mm; other finished widths on request |
| Coil net weight | Specify required MT/coil and maximum decoiler or crane loading |
| Coil inner diameter (ID) | 508 / 610 mm as enquiry references, subject to mill confirmation |
| Edge condition | Mill edge or slit / trimmed edge, per available processing route |
| Surface / condition | As-rolled mill-scale finish; pickled and oiled options subject to enquiry |
| Inspection documents | MTC showing heat identity, chemistry, tensile results and ordered tests |
Q355B is a low-alloy structural grade. These reference maximum limits relate to the grade and the specified hot-rolled product condition, while the actual coil chemistry is recorded by heat in its mill test certificate.
| Element | Reference mass fraction for Q355B |
|---|---|
| Carbon (C) | ≤ 0.24% |
| Silicon (Si) | ≤ 0.55% |
| Manganese (Mn) | ≤ 1.60% |
| Phosphorus (P) | ≤ 0.035% |
| Sulfur (S) | ≤ 0.035% |
| Chromium (Cr) | ≤ 0.30% |
| Nickel (Ni) | ≤ 0.30% |
| Copper (Cu) | ≤ 0.40% |
Reference limits above are for the commonly quoted Q355B hot-rolled range. The governing GB/T 1591 edition includes detailed rules, notes and thickness conditions. Verify the specific heat analysis, additional microalloying elements and any project carbon-equivalent or welding limits on the certified MTC.
Q355B is selected where higher structural strength is required than general-purpose mild steel. GB/T 1591 requirements are defined by thickness, test direction, product form and the applicable delivery specification.
Nominal Q355 grade minimum yield-strength reference for the relevant thickness group. Thin-coil testing provisions require product-standard review.
GB/T 1591 hot-rolled material reference for the relevant thickness range and acceptance condition.
Reference longitudinal Charpy energy 34 J for standard-size specimens, with specimen size, thickness and required testing to be confirmed.
| Nominal thickness | Minimum yield reference | Tensile reference | Elongation reference |
|---|---|---|---|
| t ≤ 16 mm | ≥ 355 MPa | 470–630 MPa | ≥ 22% longitudinal / ≥ 20% transverse |
| 16 < t ≤ 40 mm | ≥ 345 MPa | 470–630 MPa | ≥ 22% longitudinal / ≥ 20% transverse |
Different strength grades can affect thickness design, weld procedures and allowable forming. Obtain project engineering approval before changing a specified grade.
Specify the finish that matches your manufacturing process. Edge condition, strip flatness and surface scale affect downstream slitting, decoiling and fabrication.
Normal hot rolling produces a scale-bearing surface. Request surface preparation if the project requires a different finish.
Confirm required width, tolerance, edge condition and winding quality for the intended processing line.
A complete coil schedule prevents mismatches between ordered steel, downstream equipment and export logistics.
State nominal gauge, the required tolerance class and the acceptance test conditions for Q355B.
Specify as-rolled or finished slit width, edge quality and allowable camber.
Provide nominal inner diameter and maximum single-coil net weight allowed by your line and crane.
Agree material documents, surface protection, straps, coil eye orientation and unloading constraints.
Send a spreadsheet, drawing or procurement schedule with per-size tonnage.
Q355B coils support fabrication routes requiring defined structural strength. Forming, welding and final component acceptance depend on product thickness and the approved engineering specification.
Cut-to-length strip and formed blanks for equipment frames, brackets and structural parts.
Where suitable for the tube product standard, high-strength hot rolled strip can be used for roll forming and welded profiles.
Engineered load-bearing steel components with defined material strength requirements.
Master coils processed into narrower coils, cut sheets and profile blanks.
Approved structural components fabricated to project drawings and welding procedures.
Strength-defined strip feedstock where production and product requirements permit.
Procurement by coil size, grade, inspection and lot requirements.
Steel stock for engineered fabrications subject to approved design and quality controls.
Estimate theoretical strip length using nominal thickness, width and net coil weight. Useful when planning slitting runs, cut-length schedules and steel conversion tonnage.
Basis: nominal Q355B planning density 7.85 g/cm³. kg/m = thickness (mm) × width (mm) × 0.00785. Length (m) = net coil kg ÷ kg/m. Actual dimensions, thickness variation, coil tail/head conditions and invoiced net weight may change the result. Packaging and coil-eye dimensions are excluded.
Hot rolling converts steel slab to strip and subsequent winding forms master coils for industrial processing. Order thickness, width, grade, surface and final coil weight influence the mill schedule and downstream handling plan.
Coordinate grade requirements, production availability and logistics with a dedicated steel supply team.
Actual annual output across the company's steel business, not a claim for Q355B coil alone.
Manufacturing ↗Company-wide steel inventory; confirm Q355B coil lots and sizes for your specific order.
Steel Inventory ↗Agree the MTC, heat identification, mechanical results and any additional inspection before dispatch.
Quality Control ↗Consolidate product details, handling limits, packaging and delivery terms within one project enquiry.
Specify the downstream form needed for your factory line. Services are evaluated by coil size, ordered quantity, tolerance and facility availability.
Request narrower coils for tubing, roll-forming and precision feed lines, with defined width tolerance and edge finish.
Convert hot rolled coil into flat sheets based on a length and flatness schedule.
Ask about prepared-surface supply when additional scale removal or short-term handling protection is needed.
Attach your processing drawing or specifications in the RFQ.
Define the technical acceptance plan with your purchase order. Review grade identification, heat analysis, mechanical testing and dimensional checks for the agreed product scope.
Send the required thickness, finished width and tonnage to check an appropriate Q355B HRC supply route. We will confirm mill or stock-origin details, lot sizes and an order-specific lead time.
The regular 1 million MT inventory figure refers to company-wide steel inventory. Confirm Q355B coil lots, dimensions and delivery lead time by enquiry.
Steel Inventory ↗Export planning begins with coil net weight, handling limits and destination. Request appropriate steel strapping, edge protection and moisture-control measures for transport and unloading conditions.
Explore general-purpose, structural and forming grades. Every grade should be ordered against its own applicable product and inspection standard.
Specify the grade and delivery form clearly to receive a useful material offer and matching test documents.
GB/T 1591-2018 defines the Q355B high-strength low-alloy structural grade. GB/T 3274-2017 covers relevant hot-rolled plate, sheet and strip products, and GB/T 709-2019 addresses hot-rolled steel dimensions and tolerances. Confirm product form and applicable clauses in the purchase order.
For applicable hot-rolled material of nominal thickness up to 16 mm, common GB/T 1591 references include minimum yield 355 MPa and tensile 470–630 MPa. Thicker product groups have different yield minima. Thin-coil testing conditions and the MTC control actual acceptance.
Q355B is a higher-strength low-alloy structural grade, while Q235B is a general carbon structural grade. They have different chemistry and mechanical requirements. Changing a design grade requires an approved engineering review rather than automatic substitution.
Q355B quality grade B has a +20°C Charpy reference. Whether impact testing applies to a particular coil, and the energy, specimen size and orientation required, depend on the ordered specification and material thickness. Include the exact test requirement in the RFQ.
Slitting and cut-to-length requests can be evaluated by coil thickness, finished width, processing tolerance, edge type and quantity. Provide drawing and final size requirements with the order.
For planning density 7.85 g/cm³, kg per running meter equals thickness (mm) × width (mm) × 0.00785. Divide the net coil kilograms by kg per meter to estimate strip length. Actual gauge variation and net coil weight change the resulting length.
Specify GB/T 1591 grade, hot-rolled product standard, thickness, width, tolerances, surface, edge condition, coil ID, MT per coil, total quantity, heat-number/MTC requirements, impact-test needs, destination and delivery terms.
Share your thickness, width, total tonnage, coil ID and delivery destination. Receive an order-specific quotation with verified product form, material standard, inspection scope and delivery conditions.
Send your required grade, dimensions, quantity and destination. Our team will review the inquiry.