S355JOH Seamless Square TubeEuropean-standard steel, with chemical composition primarily including carbon, silicon, manganese, phosphorus, sulfur, and niobium, featuring a carbon content of 0.22% and manganese content up to 1.6%.

Q355B Square and Rectangular Steel TubeIt is a low-alloy high-strength structural steel by Zhongzhun, with "Q" indicating the yield point, "355" representing the yield strength of 355MPa, and "B" denoting the quality grade. Its chemical composition mainly includes carbon, silicon, manganese, phosphorus, sulfur, etc., and may have some differences in component ratios compared to S355JOH.

Production Process

S355JOH Seamless Square PipeTypically manufactured through cold drawing or hot rolling of ingots, these processes yield high dimensional accuracy.

Q355B Square and Rectangular Steel PipeThe production process includes steps such as raw material preparation, heating and piercing, rolling into shape, heat treatment, and finishing inspection. Generally, Q355B steel plates or billets are used as the raw material, which are then cold-bent and high-frequency welded to form the product, with some also using hot rolling technology.

Performance Features

IntensifyBoth products offer a yield strength of 355MPa, providing high tensile strength capable of withstanding significant pressure and loads, meeting the demands of various engineering structures.

Corrosion resistanceThe S355JOH seamless square tube exhibits certain corrosion resistance, suitable for various harsh environments; the Q355B square tube, with proper corrosion protection treatment, can also significantly enhance its resistance to atmospheric, water, and soil corrosion.

ResilienceThe S355JOH seamless square tubes offer excellent toughness and performance; the Q355B square rectangular tubes, after proper heat treatment, demonstrate superior low-temperature impact toughness, ensuring safe use in extreme climate conditions.

Processing capabilitiesS355JOH seamless square tubes boast excellent processing properties due to their composition and manufacturing process, allowing for bending and welding. Q355B square rectangular tubes have superior welding performance, high weld strength, and are less prone to cracking, making them convenient for on-site installation and construction. They also exhibit good cold working formability.

Application Fields

Construction IndustryS355JOH seamless square tubes are commonly used for construction formwork, steel structures, and cladding structures, etc.; Q355B square rectangular tubes are often utilized in building frames, roof supports, and suspension devices, widely applied in high-rise buildings, large venues, bridges, and other projects.

Mechanical ManufacturingS355JOH Seamless Square Tubes are suitable for structural components of various mechanical equipment, such as drive shafts, gears, hydraulic cylinders, etc.; Q355B Square Rectangular Tubes are the material of choice for heavy machinery, mining equipment, and port machinery.

TransportationS355JOH Seamless Square Tubes are used for structural components in vehicles, trains, ships, and other transportation; Q355B Square Rectangular Tubes, due to their high strength-to-weight ratio, are employed in critical parts such as car frames and collision beams.

Petroleum & Chemical IndustryThe S355JOH seamless square tube is suitable for conveying corrosive media in the oil and chemical industry; the Q355B square rectangular tube is used in high-pressure vessels and pipeline systems, with its corrosion resistance and high strength ensuring stable system operation.

Dimension specifications

S355JOH Seamless Square TubeThe rectangular steel tubes we offer typically range in size from 20mm x 20mm to 500mm x 500mm, with wall thicknesses from 1.5mm to 25mm. Lengths can be customized to meet customer requirements, generally available in 6 meters or 12 meters.

Q355B Square and Rectangular Steel TubeThe size specifications are quite diverse, with common outer diameters ranging from 30mm to 900mm, wall thickness from 1mm to 30mm, and lengths around 5m to 12m. Customization is also available according to the requirements of different industries and projects.