Hollow section steel is one of the most versatile structural materials used across maritime, offshore, construction, and industrial applications. Whether you need a short run of square tubes for a structural frame or a batch of circular hollow sections cut precisely for a piping system, understanding how this material is processed and cut to size will help you order smarter and avoid costly mistakes. This guide walks you through everything from the basic types to the cutting methods and what to check before placing your order.
What is hollow section steel and what are the main types?
Hollow section steel is exactly what the name suggests: a steel profile with a hollow interior running along its length. This design gives the material an excellent strength-to-weight ratio, making it ideal for load-bearing structures where weight matters. The three main types you will encounter are:
- Circular Hollow Sections (CHS) — round tubes, commonly used in pipework, structural columns, and marine applications
- Square Hollow Sections (SHS) — equal-sided square profiles, widely used in frames, supports, and general construction
- Rectangular Hollow Sections (RHS) — oblong profiles that offer directional strength, often used in beams, trailers, and fabrication work
Each type is available in a range of wall thicknesses and dimensions. The right choice depends on the load requirements, connection method, and the environment in which the material will be used. In maritime and offshore settings, corrosion resistance is also a key factor when selecting the appropriate grade.
How is hollow section steel manufactured?
Most hollow section steel is produced through one of two main routes: hot-rolling or cold-forming.
In hot-rolling, steel is shaped at high temperatures, typically above 1,000 degrees Celsius. The material is passed through rollers and formed into the desired profile while still malleable. Hot-rolled hollow sections tend to have a slightly rougher surface finish and rounded internal corners, but they offer excellent structural integrity and are well suited for heavy-duty applications.
Cold-formed hollow sections are produced at room temperature, starting from flat-rolled steel strip. The strip is progressively bent into shape and welded along a seam. Cold-formed sections have sharper corners, tighter dimensional tolerances, and a smoother surface finish, which makes them popular in construction and light fabrication work.
For structural applications, hollow sections are typically produced to standards such as EN 10219 (cold-formed) or EN 10210 (hot-finished). In markets where ASTM standards apply, such as the United States, equivalent specifications govern the material properties and testing requirements.
What cutting methods are used for hollow section steel?
Once hollow section steel leaves the mill, it typically comes in standard lengths of six or twelve metres. For most projects, these standard lengths need to be cut down to exact dimensions. There are several methods used in professional tube processing, each with its own strengths:
- Sawing — Circular or band saws produce clean, straight cuts with minimal material loss. This is one of the most common methods for straightforward length cuts and works well across all hollow section types.
- Plasma cutting — A high-temperature plasma torch cuts through the steel rapidly. Plasma cutting is fast and handles thicker wall sections well, though it leaves a slightly rougher edge that may need finishing.
- Laser cutting — Laser cutting offers very high precision and a clean finish, making it the preferred method when tight tolerances or complex profiles are required. It is particularly useful for cut-outs, notches, and shaped ends.
- Abrasive cutting — Used in specific situations where other methods are not suitable, abrasive wheels cut through the steel but generate more heat and a rougher edge.
For maritime and offshore work, where components often need to fit precisely into existing systems, laser cutting and sawing are the most commonly specified methods. The choice depends on the required tolerance, wall thickness, and whether any secondary operations such as drilling or bevelling are needed after cutting.
How accurate can hollow section steel be cut to size?
Cutting accuracy depends on the method used and the quality of the equipment. With modern sawing and laser cutting equipment, tolerances of plus or minus one millimetre or better are achievable for standard length cuts. Laser cutting can achieve even tighter tolerances for complex profiles and shaped ends.
It is worth noting that the base material itself has dimensional tolerances defined by the production standard. Even before cutting, the outer dimensions and wall thickness of a hollow section will fall within a permitted range. When ordering cut-to-size material, make sure the supplier understands whether your tolerance applies to the finished cut length or to the overall assembled dimension, as these are not always the same thing.
For critical applications, such as offshore structural connections or hydraulic system components, always specify your required tolerance explicitly. A good supplier will flag any issues before production rather than delivering material that does not meet your needs.
What should you check before ordering hollow section steel cut to size?
Before placing an order for cut hollow sections, run through these key points to make sure you get exactly what you need:
- Material grade — Confirm the steel grade required. Common structural grades include S235, S275, and S355. For marine or corrosive environments, stainless steel or coated grades may be more appropriate.
- Dimensions and wall thickness — Specify outer dimensions and wall thickness precisely. Do not assume a standard size covers your requirement without checking.
- Cut length and quantity — Provide exact lengths and the number of pieces needed. Account for any finishing allowance if the cut ends will be machined or bevelled afterwards.
- Tolerances — State your acceptable tolerance on cut length, squareness of cut, and any profile dimensions if applicable.
- End finish — Specify whether you need square cut ends, bevelled ends, or any other preparation such as drilling or notching.
- Certifications and documentation — For offshore, maritime, or regulated construction projects, material certificates (mill certificates) are often mandatory. Confirm this with your supplier at the time of ordering.
- Surface treatment — If the hollow sections need to be primed, galvanised, or sandblasted before delivery, specify this upfront. Processing after cutting is far more efficient than treating already-installed material.
You can explore the full range of available steel products on our marine steel products page to check stock availability and standard dimensions before getting in touch.
How Marine Steel helps with hollow section steel processing
We handle the full process in-house, so you do not need to coordinate between multiple suppliers or workshops. Whether you need standard lengths or custom cut hollow sections ready for immediate use, we provide a complete solution from a single source.
- Precision cutting to your exact specifications, including tight tolerances for critical applications
- Additional processing options including bending, drilling, sandblasting, priming, and galvanising
- Hydraulic tube and fittings supply in both steel and stainless steel for complete system compatibility
- Class certification and material documentation available for maritime, offshore, and regulated projects
- Stock held at our warehouses in Rotterdam and Houston for fast turnaround
- Custom dimensions and special materials available on request
We know that waiting for materials is not an option when a vessel is in port or a project is on a tight schedule. Our team thinks along with you from the first enquiry, making sure you get the right material, cut correctly, with the right documentation, delivered without delay. Contact us to discuss your requirements and get a fast quotation.
