What Are The Types of RHS Steel?

RHS steel (https://www.eastern-steels.com/products/rhs-steel.html) , stands rectangular tubes, is a common type of steel characterized by its rectangular cross-section and hollow interior. RHS steel can be categorized into several types based on manufacturing processes, materials, and applications. The core classification dimensions and scenario adaptation logic are clear, ensuring that corresponding products can be matched to different scenario needs.

RHS Steel Classification by Manufacturing Process
1. Welded Rectangular Tubes
Welded rectangular tubes are made by bending steel plates or strips into rectangular cross-sections and then welding the joints using methods such as submerged arc welding or high-frequency welding. This type accounts for over 80% of the rectangular tube market.

Advantages of welded rectangular tubes:
Welded rectangular tubes have high production efficiency and low cost (30%-50% lower than seamless rectangular tubes). They can be processed into large-size tubes (e.g., 600mm × 400mm) and are suitable for "low to medium load, non-precision" scenarios, such as construction scaffolding, outdoor billboard frames, and general machinery supports.

Disadvantages of welded rectangular tubes:
The weld strength of welded rectangular tubes is slightly lower (10%-15% lower than the base material), making them unsuitable for high-pressure or high-fatigue-load applications.

2. Seamless Rectangular Tubes
Seamless rectangular tubes are made by cold-drawing or hot-rolling seamless tubes (https://www.eastern-steels.com/product/seamless-steel-pipe.html) into rectangular sections, eliminating weld seams and offering high strength and excellent sealing.

Advantages of seamless rectangular tubes:
Seamless rectangular tubes have a yield strength 20%-30% higher than welded tubes of the same specifications, allowing them to withstand high pressure (such as hydraulic system pipelines) and alternating loads. They are suitable for "high-precision, high-reliability" applications, such as automotive chassis frames, aerospace ground equipment structural components, and high-pressure fluid transport pipelines (such as chemical raw material transport).

Disadvantages of seamless rectangular tubes:
The manufacturing process for seamless rectangular tubes is complex and costly, and their specifications are limited (maximum cross-section is typically ≤300mm × 200mm), limiting their application to special needs.

RHS Steel Classification by Material:
1. Carbon Steel Rectangular Tubes
Carbon steel rectangular tubes are made of materials such as Q235 and Q345, with low carbon content (≤0.25%), low cost, and easy processing. Yield strength is 235-345 MPa.

Suitable for "general structural support" scenarios, such as building beams, furniture frames, and logistics racks.

Q345 RHS steel has higher strength and can be used for small and medium-sized engineering machinery frames (such as small loader chassis).

2. Alloy Steel Rectangular Tubes
Alloy steel rectangular tubes are made of materials such as 40Cr and 16Mn, containing alloying elements such as manganese and chromium. Yield strength is ≥345 MPa, and temperature resistance and fatigue resistance are superior to carbon steel.

Suitable for "medium to high load, complex working conditions" scenarios, such as heavy machinery frames (such as excavator chassis), high-pressure equipment support structures, and low-temperature environment building components (such as temporary factory frames for winter construction in Northeast China).

3. Stainless Steel Rectangular Tubes
Stainless steel rectangular tubes are made of 304 or 316 stainless steel, containing ≥12% chromium, possessing excellent corrosion resistance and a smooth, aesthetically pleasing surface.

Suitable for "corrosive environments, cleanrooms, or decorative scenarios," such as equipment frames in food processing plants (304 material, meeting hygiene standards), marine engineering structural components (316 material, resistant to seawater corrosion), and interior decorative columns (such as decorative borders in shopping malls and hotels).

RHS Steel Classification by Surface Treatment
1. Black Rectangular Tubes
Black rectangular tubes have no surface treatment, with an oxide scale on the surface, offering the lowest cost.

Suitable for "indoor non-corrosive environments requiring subsequent painting," such as internal frames of mechanical equipment (subsequent application of anti-rust paint), and embedded parts in buildings (concealed installation, aesthetics not a concern).

2. Galvanized Rectangular Tubes
Galvanized rectangular tubes are treated with hot-dip galvanizing or cold galvanizing, with a zinc layer thickness ≥85μm (hot-dip galvanizing) or 10-20μm (cold galvanizing).

They have strong corrosion resistance and are suitable for outdoor, humid environments, such as outdoor billboards, municipal guardrails, and water pipe supports (hot-dip galvanizing has a lifespan of 15-20 years).

3. Painted Rectangular Tubes
Painted rectangular tubes are coated with anti-rust paint or topcoat, offering good aesthetics and suitable for indoor and outdoor decorative structures, such as furniture frames (decorative paint), exhibition stand frames (colored topcoat), and interior partitions (matte paint).

Read more:
What Does RHS Steel Mean?: https://www.eastern-steels.com/newsdetail/what-is-rectangular-tube.html
or
SHS Steel VS. RHS Steel: https://www.eastern-steels.com/newsdetail/what-is-the-difference-between-shs-and-rhs-steel-.html

No. 229, Tongzipo West Road, Lugu International Industrial Park, Yuelu District, Changsha, China

Eastern Steel Manufacturing Co.,Ltd is a leading manufacturer and distributor of seamless steel pipe, welded steel pipe, OCTG products and fittings. We supply first-step processing, semi-finished parts and finished parts to help our clients meet fabrication requirements beyond their capacity or to improve operations by moving forward the pre-production processing.

This release was published on openPR.