S235JR Square Tube Carbon Steel Square Tube for Industrial Use

Material

S235JR is a non-alloy structural (mild) carbon steel grade used for general-purpose load-bearing fabrication. In cold-formed square hollow sections (SHS), steel strip/plate is roll-formed at ambient temperature, welded (typically high-frequency), and then sized to achieve stable geometry and consistent dimensions.
Note on designation: for European hollow sections, the grade is often specified as S235JRH under EN 10219 (the “H” suffix indicates hollow section). Cold-formed SHS produced to EN 10219 is a common way to purchase “S235JR square tube” for structural/industrial frames.

Specifications

• Shape: Square Hollow Section (SHS) / Square Tube

• Manufacturing: Cold formed + welded + sizing

• Typical OD range (customizable): 20×20 mm up to 400×400 mm

• Typical wall thickness (customizable): 1.5–16.0 mm (heavier walls available by agreement)

• Length options: 6 m / 12 m / cut-to-length

• Ends: Plain, deburred, or beveled (upon request)

• Surface options: Black (mill finish), oiled, shot-blasted, zinc-coated / hot-dip galvanized (upon request)

Main Features

• Reliable strength-to-weight ratio for frames, racks, supports, and welded assemblies

• Excellent weldability and workshop fabrication performance (cutting, drilling, punching)

• Clean appearance and stable geometry after sizing—ideal for exposed structures and modular fabrication

• Closed-section stiffness improves torsional rigidity versus open sections

Our Advantages

Q1: “Which standard should I specify—EN 10219 or EN 10210?”

• We help you choose correctly: EN 10219 = cold-formed, EN 10210 = hot-finished. Cold-formed tubes are typically selected for cost efficiency and precise geometry; hot-finished is often chosen when hot-finish performance is required by design.

Q2: “Can you control dimensional tolerances and corner quality?”

• We control OD, wall thickness-on-flats, straightness, and corner consistency per the requested standard (e.g., EN 10219-2 tolerances). For projects referencing US-style tolerance practices, we also follow recognized measurement methods (e.g., avoid weld-seam area for thickness checks; corner radius limits for square/rectangular tubing).

Q3: “Do you provide full traceability and inspection documents?”

• Each bundle can be traceable by heat number, and we provide inspection documents (MTC) so buyers can verify grade/standard, heat/lot, and test results.

Q4: “Is weld seam quality reliable for fabrication?”

• We focus on stable forming + welding parameters and post-weld sizing to ensure consistent seam integrity and smooth fabrication performance (especially important for load-bearing frames and repetitive production).

Q5: “Can you support processing and delivery requirements?”

• Cut-to-length, end finishing, bundling/labeling, protective packing, and export documentation are available to reduce your receiving and fabrication time.

Chemical Composition

Mechanical Properties

Execution Standards (ASTM / EN / GOST / JIS / GB)

EN (Europe)

• EN 10219-1: Cold formed welded structural hollow sections — technical delivery conditions

• EN 10219-2: Tolerances, dimensions and sectional properties

• EN 10025-2: Non-alloy structural steels (basis for S235/S275/S355 grade definitions)

• EN 10204: Inspection documents (MTC types such as 3.1/3.2) (commonly requested)

ASTM (USA)

• ASTM A500/A500M: Cold-formed welded and seamless carbon steel structural tubing in rounds and shapes (square/rectangular included)

JIS (Japan)

• JIS G 3466: Carbon steel square and rectangular tubes for general structure

GB (China)

• GB/T 6728: Cold forming sectional steel for general structure (square/rectangular hollow sections included)

GOST (Russia/EAEU)

• GOST 30245: Steel bent closed welded square and rectangular sections for building structures

Application Areas

Main industries: steel structures, industrial equipment, fabrication workshops, logistics & storage, infrastructure supports, energy and utility frames.

Typical uses inside these industries

• Structural framing: columns, beams, trusses, bracing members

• Industrial equipment: machine bases, guards, platforms, conveyors

• Racking & logistics: pallet racks, mezzanines, shelving frames

• Vehicles & transport: trailer frames, subframes, reinforcements

• Energy & utilities: support frames, skids, mounting structures

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.