Set 1
Q: What's the difference between Q235 and Q345b?
A: Q235 and Q345b differ significantly in strength, composition, and application. Q235 is plain carbon steel with a minimum yield strength of 235 MPa, while Q345b is low-alloy high-strength steel with 345 MPa yield strength. Q345b contains manganese and silicon alloys that boost its load-bearing capacity, making it suitable for heavy-duty projects. Q235 has better weldability and lower cost, ideal for light frames. Q345b also requires 20°C impact testing for toughness, critical for seismic or outdoor use. Choose Q235 for budget-friendly, low-load builds; Q345b for high-rises, bridges, or heavy industry.
Q: Are Ss400 H-beams hot rolled?
A: Yes, all our Ss400 H-beams are hot rolled, a process that enhances their quality and performance. Hot rolling heats steel billets to 1100-1250°C, then shapes them into H-sections via rolling mills. This creates a uniform grain structure, improving ductility and toughness-key for structural stability. The hot rolled surface (natural black mill scale) is easy to process, and the method ensures consistent dimensional accuracy. Ss400's hot rolled form also boosts weldability and bendability, fitting construction needs. Every Ss400 H-beam undergoes hot rolling to meet JIS G3101 standards.
Q: Can Q345b I-beams be used for bridges?
A: Absolutely, Q345b I-beams are excellent for bridge construction. Their 345 MPa yield strength withstands dynamic vehicle loads and environmental stress. The I-shape's high moment of inertia efficiently distributes weight, reducing structural strain. Q345b's impact resistance (from 20°C testing) handles temperature fluctuations and seismic activity. They're used for small to medium-span bridges, as well as bridge girders and supports. For coastal bridges, add galvanizing to resist corrosion. Q345b's strength-to-weight ratio saves material costs while ensuring safety-many bridge projects specify it.
Q: What sizes are available for Q235 H-beams?
A: We offer Q235 H-beams in a wide range of sizes for diverse projects. Small sizes include 100×100×6×8mm (17.2kg/m) for light frames and 125×125×6×9mm (19.8kg/m) for mezzanines. Medium sizes like 150×150×7×10mm (26.1kg/m) and 200×200×8×12mm (37.3kg/m) suit workshops. Large sizes such as 300×300×10×15mm (85.1kg/m) work for industrial structures. Standard lengths are 6m, 9m, 12m, with custom cuts available. We stock common sizes for quick delivery and can produce custom dimensions for bulk orders. Our size chart includes weight, flange/web thickness, and load capacity data.
Q: Is Ss400 easier to weld than Q345b?
A: Ss400 is slightly easier to weld than Q345b, but both are highly weldable. Ss400 (plain carbon steel) has lower carbon and no heavy alloys, so it needs no preheating for thicknesses under 25mm. It works with basic E43-series rods and common methods like manual arc welding. Q345b (low-alloy steel) may require mild preheating (100-150°C) for thick sections and E50-series rods to match strength. Both produce strong welds, but Ss400 is more forgiving for on-site teams with basic equipment. For projects prioritizing welding simplicity, Ss400 is preferable; Q345b works with proper technique.
Set 2
Q: What's the load capacity of Q345b 200×200 H-beams?
A: The load capacity of Q345b 200×200 H-beams depends on thickness and span. A 200×200×8×12mm model (37.3kg/m) with a 6m span supports ~25-30 tons of uniform load. At 8m, capacity drops to 14-18 tons. Q345b's 345 MPa yield strength ensures it resists bending and shear forces. The 8mm web handles lateral stress, while 12mm flanges bear vertical loads. It's ideal for heavy mezzanines, crane beams, or high-rise columns. For precise calculations, we need your project's span, support type (fixed/simple), and load type (static/moving). Our engineers can provide custom capacity reports.
Q: Are Q235 I-beams cheaper than Ss400?
A: Yes, Q235 I-beams are typically 10-15% cheaper than Ss400 for the same size. Q235 is a domestic Chinese grade with abundant raw material supply and simpler production (plain carbon steel). Ss400 (JIS standard) often involves stricter manufacturing or import costs. For example, a 150×150mm Q235 beam costs ~$470/ton, while Ss400 is ~$530/ton. Q235 suits budget-sensitive projects like small workshops or residential frames. Ss400's extra cost is justified for Asian projects requiring JIS standards or better processability. We provide detailed quotes to compare based on your order size.
Q: Can Ss400 H-beams be cut to 7m length?
A: Yes, Ss400 H-beams can be cut to 7m lengths with high precision. Our standard Ss400 beams come in 6m, 9m, 12m, but we use plasma or flame cutters for custom lengths. Ss400's low carbon content makes cutting smooth, with clean edges and no cracks. The cutting tolerance is ±2mm, fitting your construction drawings. After cutting, we remove burrs for safe handling. Cutting to 7m adds just 1-2 working days to delivery-no extra fees for standard custom cuts. Just specify the length when ordering, and we'll process it from stock or production batches.
Q: What projects use Q345b I-beams?
A: Q345b I-beams are used in heavy-duty construction and industrial projects. High-rise buildings rely on them for core walls and beam-column connections, as they bear vertical loads and resist wind. Industrial applications include large workshop frames, crane rails (for 10+ ton cranes), and equipment bases. Infrastructure projects like highway overpasses and railway bridges use Q345b for girders. They're also in power plants and steel structures needing high strength. Q345b's toughness makes it mandatory for seismic zones. Any project requiring high strength and durability benefits from Q345b I-beams.
Q: Do Q235 H-beams meet GB standards?
A: Yes, all our Q235 H-beams fully comply with Chinese GB/T 700 standards. We source them from GB-certified mills that adhere to strict requirements: 235 MPa minimum yield strength, 370-500 MPa tensile strength, and elongation ≥26%. Each batch undergoes tests for chemical composition (carbon ≤0.22%, manganese ≤1.40%) and mechanical properties. We provide mill test certificates (MTCs) with every order, detailing test results and GB compliance. For domestic Chinese projects or those requiring GB materials, Q235 H-beams are fully qualified. Third-party testing (e.g., CMA) is available upon request.
Set 3
Q: What's the difference between I-beams and H-beams?
A: I-beams and H-beams differ in cross-section, strength, and application. I-beams have a narrow flange (top/bottom) and thick web (middle), suited for bending loads in one direction. H-beams have wider, equal-flange sections, offering balanced strength in both directions. H-beams handle heavier loads and larger spans than same-size I-beams. I-beams are used for light frames, purlins, or beams with single-direction loads. H-beams suit heavy structures: high-rises, bridges, or workshop frames. H-beams also have better weldability for complex connections. Choose I-beams for light, directional loads; H-beams for heavy, multi-directional loads.
Q: Can Q235 H-beams be used outdoors?
A: Yes, Q235 H-beams can be used outdoors with proper corrosion protection. Q235's plain carbon steel has no natural rust resistance-its mill scale only offers temporary protection. For outdoor use, treat it with hot-dip galvanizing, anti-corrosive paint, or epoxy coating. Galvanizing adds a zinc layer, extending lifespan by 15+ years in humid areas. Paint is cost-effective for dry climates. Q235's good weldability lets you repair or modify outdoor structures easily. It's used for outdoor canopies, agricultural barns, and temporary shelters. With protection, Q235 performs reliably outdoors without sacrificing strength.
Q: What's the weight per meter of Ss400 150×150 I-beams?
A: The weight per meter of Ss400 150×150 I-beams varies by flange/web thickness. A common 150×75×5×7mm model weighs ~14.3kg/m. A thicker 150×80×6×9mm version is ~18.1kg/m. Weight depends on cross-sectional area-thicker flanges and web add mass and bending strength. Ss400's density (7.85g/cm³) is consistent with carbon steels, so weight correlates to load capacity. The 14.3kg/m model supports ~8 tons at 6m span; the 18.1kg/m model handles ~11 tons. We provide a weight chart for all Ss400 I-beam sizes, aiding logistics planning and cost estimation. Specify thickness for exact weight.
Q: Is Q345b stronger than Ss400?
A: Yes, Q345b is significantly stronger than Ss400. Q345b has a minimum yield strength of 345 MPa, while Ss400 offers 235 MPa-Q345b can bear 47% more load before deformation. For example, a 200×200mm Q345b beam has a bending capacity of ~35 kN·m, versus 24 kN·m for Ss400 of the same size. Q345b's alloy content (manganese, silicon) enhances strength without losing ductility. Ss400 works for light to medium loads, but Q345b is better for heavy-duty applications like high-rises or bridges. However, Ss400 is cheaper and easier to process. Choose Q345b for strength-critical projects; Ss400 for cost-sensitive, low-load builds.
Q: Can Q345b H-beams be bent?
A: Yes, Q345b H-beams can be bent into custom shapes with professional equipment. Though high-strength, Q345b has good ductility (elongation ≥21%) for bending. We use hydraulic bending machines that apply gradual pressure to avoid cracking. For thicknesses ≤12mm, no preheating is needed; thicker sections require mild preheating (100-150°C). The maximum bend angle depends on size-smaller beams bend to 90°, larger ones need larger radii. We test sample bends first to meet your specs. Bent Q345b beams are used in curved bridges, architectural arches, or industrial frames. The process adds 2-3 days to lead time.
Set 4
Q: What's the lead time for Ss400 I-beams?
A: Lead time for Ss400 I-beams depends on quantity and size. Stock sizes (100×100mm, 150×150mm) in small batches (≤50 tons) ship in 7-10 working days. Large orders (≥100 tons) or custom sizes take 12-15 days for hot rolling. Adding services like cutting or galvanizing adds 2-3 days. Rush orders (≤30 tons) can be fulfilled in 5-7 days with priority production. We maintain inventory of common Ss400 sizes to shorten lead times. For international shipping, add 2-4 weeks based on destination. After order confirmation, we send production updates to ensure on-time delivery.
Q: Are Q235 I-beams suitable for workshops?
A: Yes, Q235 I-beams are ideal for most workshop construction. Q235's 235 MPa yield strength supports light to medium loads, like roof trusses, mezzanines, or 5-ton cranes. Its good weldability allows easy assembly of workshop frames, even on-site. Q235's low cost fits workshop budget needs, especially for small to medium facilities. The I-shape's design efficiently bears bending loads from equipment or materials. Q235 I-beams are available in sizes from 100×68mm to 250×118mm, matching workshop span requirements. Many manufacturers use Q235 I-beams for their balance of performance and cost.
Q: Do Q345b H-beams come with certificates?
A: Yes, all Q345b H-beams include comprehensive quality certificates. Each batch has a mill test certificate (MTC) complying with GB/T 1591 standards, detailing chemical composition (manganese 1.00-1.60%, silicon 0.20-0.55%) and mechanical properties (yield ≥345 MPa, tensile 470-630 MPa). The MTC includes 20°C impact test results (required for "b" grade) and dimensional tolerances. For international projects, we provide English certificates and can meet ASTM/EN standards if needed. Third-party testing (e.g., SGS, BV) is available upon request. These certificates ensure Q345b meets your project's quality and compliance requirements.
Q: What's the surface finish of Ss400 H-beams?
A: Ss400 H-beams have a natural black, mill-scale surface finish from hot rolling. Mill scale is a thin iron oxide layer formed when heated steel contacts air, offering temporary rust protection during storage/transport. The finish is rough, improving adhesion for paints or coatings. For projects needing a smoother surface, we can provide sandblasting to remove mill scale. Ss400's surface accepts galvanizing, painting, or epoxy coating well-critical for outdoor or corrosive environments. We store beams in dry warehouses to preserve the surface, and pre-treated options are available for immediate use.
Q: Can Q235 and Q345b be welded together?
A: Yes, Q235 and Q345b can be welded together with proper materials and technique. Use a welding rod matching the lower-strength material (Q235) to avoid brittle welds-E43-series rods (e.g., E4315) work best. These rods bond well with both grades and ensure weld strength matches Q235. For Q345b sections thicker than 12mm, preheat the Q345b side to 100-150°C to reduce stress. Control heat input to prevent alloy dilution in Q345b. This weld combination is common in projects mixing cost-effective Q235 (non-critical parts) and high-strength Q345b (load-bearing parts). Our team provides welding parameters for optimal results.
Set 5
Q: Which grade is best for high-rises: Q345b or Ss400?
A: Q345b is far better than Ss400 for high-rise construction. Q345b's 345 MPa yield strength is 47% higher, enabling it to bear vertical loads of tall buildings and resist wind/seismic forces. High-rises need compact components-Q345b allows smaller beam sections than Ss400 for the same load, saving space. Its 20°C impact resistance prevents brittle fracture during earthquakes. Ss400 works for low-rises (≤5 stories), but Q345b is the industry standard for 10+ story buildings. It's used for core walls, columns, and beam-column connections, ensuring structural stability. Q345b's strength makes it irreplaceable for high-rises.
