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China Square Steel Pipe (SHS) Suppliers - High-Quality Factory Direct Carbon Steel Hollow Sections
Detailed Description of Square Steel Pipe (SHS)
Square Hollow Section (SHS) is a structural pipe manufactured by high frequency resistance welding (ERW) or thermoforming process. ERW process cold bends the steel strip into a round pipe and welds it, then presses the square through the calibrating roll, and heat treats it to eliminate the stress after welding, so the dimensional accuracy reaches ±0.5mm. Thermoforming process heats the round pipe billet to 900–950°C and expands the square hydraulically, so it realizes the homogeneous structure without weld seams, and the uniformity of the wall thickness is more than 95%. The closed section provides excellent torsional resistance. High strength and light weight (HSLA steel strength ≥355MPa), right-angled edges are easy to weld around the whole circumference, which is the preferred solution for building frames, machinery trusses and other load-bearing structures.
Dimensional Accuracy ±0.5mm
Wall Thickness Uniformity >95%
HSLA Strength ≥355MPa
Excellent Torsional Resistance
Full-Circumference Weldability
Key Parameters for Square Steel Pipe
| Parameter | Details |
|---|---|
| Manufacturing Process | ERW (Cold Formed or Hot Formed), Seamless (less common for SHS) |
| Standards | ASTM A500 (Gr. A, B, C, D) EN EN10219 (S235JRH, S275J0H, S275J2H, S355J0H, S355J2H, S355K2H), EN10210 (S235JRH, S275J0H, S275J2H, S355J0H, S355J2H, S355NH, S355NLH) JIS G3466 (STKR400, STKR490) AS/NZS 1163 (C250, C350, C450) |
| Steel Grade | Q195, Q235, Q345 (Chinese Standards); Gr. A, B, C, D (ASTM A500); S235, S275, S355 (EN Standards); STKR400, STKR490 (JIS) |
| Size (Side × Side) | 15×15mm to 500×500mm (larger sizes may be available) |
| Wall Thickness (WT) | 0.8mm to 25mm (varies with size and standard) |
| Length | Usually 6m or 12m; can be customized (e.g., 5.8m for container loading) |
| Corner Radius | Typically 2T to 3T (T = Wall Thickness), varies by standard |
| Surface Treatment | Black (bare/self-color), Oiled, Galvanized (Hot-dip or Pre-galvanized), Painted/Powder Coated |
| Inspection | Dimensional Check, Tensile Test, Yield Strength, Elongation, Weld Test (for ERW), Chemical Analysis |
Frequently Asked Questions (FAQ)
Q
What is the difference between ERW and thermoforming processes for Square Steel Pipe (SHS)?
ERW (Electric Resistance Welding) cold-bends a steel strip into a round pipe, welds it, and then presses it into a square shape through calibrating rolls, achieving a dimensional accuracy of ±0.5mm. Thermoforming heats a round pipe billet to 900–950°C and hydraulically expands it into a square, resulting in a seamless, homogeneous structure with wall thickness uniformity exceeding 95%. Thermoformed SHS is generally preferred for high-stress structural applications due to the absence of a weld seam.
Q
What international standards apply to Square Hollow Sections (SHS)?
SHS is produced under multiple international standards including ASTM A500 (Grades A, B, C, D) for North American markets, EN10219 and EN10210 for European markets (covering grades such as S235JRH, S275J0H, S355J2H, etc.), JIS G3466 (STKR400, STKR490) for Japanese standards, and AS/NZS 1163 (C250, C350, C450) for Australian and New Zealand markets. Chinese domestic grades include Q195, Q235, and Q345.
Q
What size range is available for Square Steel Pipes?
Standard Square Hollow Sections are available in sizes ranging from 15×15mm up to 500×500mm, with wall thicknesses from 0.8mm to 25mm depending on the size and applicable standard. Custom sizes beyond this range may also be available upon request from manufacturers. Standard lengths are typically 6m or 12m, with customized lengths such as 5.8m available for optimized container loading.
Q
What surface treatment options are available for Square Steel Pipes?
Square Steel Pipes can be supplied with various surface treatments depending on the application environment and customer requirements. Common options include: Black (bare/self-color) for general structural use, Oiled for short-term corrosion protection during transit, Hot-dip Galvanized or Pre-galvanized for long-term corrosion resistance in outdoor or humid environments, and Painted or Powder Coated for aesthetic and additional protective purposes.
Q
Why is Square Hollow Section (SHS) preferred for structural applications?
SHS offers several structural advantages: its closed cross-section provides excellent torsional and bending resistance compared to open sections. The right-angled edges allow full-circumference welding, making connections simpler and stronger. High-strength low-alloy (HSLA) steel grades with yield strength ≥355MPa ensure a high strength-to-weight ratio, reducing overall material usage. These properties make SHS ideal for building frames, machinery trusses, and other load-bearing structures.
Q
What quality inspections are performed on Square Steel Pipes before delivery?
Quality control for SHS typically includes a comprehensive range of tests: Dimensional Check to verify size tolerances, Tensile Test and Yield Strength measurement to confirm mechanical properties, Elongation Test to assess ductility, Weld Test (specifically for ERW pipes) to evaluate weld integrity, and Chemical Analysis to verify the material composition meets the specified grade requirements. These inspections ensure the product conforms to the applicable international standards before shipment.