What are the functions of rectangular tubes
Source：
ridui.cn Release date： 2025-08-25
Information summary：Rectangular pipes (also known as square rectangular steel pipes, hollow pipes with rectangular or square cross-sections) are widely used in various fields such as construction, machinery, transportation, and home furnishings due to their stable mechanical properties, high utilization of cross-sections, and regular shapes. Their core functions can be centered around four core scenarios: structural
Rectangular pipes (also known as square rectangular steel pipes, hollow pipes with rectangular or square cross-sections) are widely used in various fields such as construction, machinery, transportation, and home furnishings due to their stable mechanical properties, high utilization of cross-sections, and regular shapes. Their core functions can be centered around four core scenarios: structural support, frame construction, fluid transportation, and decorative protection. The specific classification and application details are as follows:
1、 Structural support and load-bearing: The core function is "load resistance, stable force transmission"
The hollow structure of rectangular pipes combines "lightweight" and "high rigidity" (under the same weight, the bending and torsion resistance of rectangular sections is much better than that of circular pipes), making it the core component of various load-bearing structures, mainly used to withstand vertical pressure, lateral tension or complex loads.
1. In the field of construction engineering
Steel structure building skeleton: used for columns and beams of multi story steel structure factories, load-bearing frames of light steel structure residences (such as wall keels and roof purlins), and secondary trusses of large-span spatial structures (such as sports halls and exhibition centers).
Advantages: The connection between rectangular cross-section and other components (such as floor slabs and wall panels) is more fitting (can be directly fixed by bolts or welding without the need for additional connectors), and under the same cross-sectional area, the bending strength of rectangular pipes is 20% -30% higher than that of circular pipes, which can reduce material consumption while ensuring structural stability.
Curtain wall and decorative structure support: vertical support keel for glass curtain wall, horizontal load-bearing bracket for dry hanging stone.
Advantages: The planar cross-section of the rectangular tube can be closely adhered to the curtain wall panels (glass, stone), avoiding the appearance of exposed keels. At the same time, the hollow structure reduces the overall weight of the curtain wall and lowers the load pressure on the building body.
Temporary buildings and scaffolding: Assembled temporary factory buildings, vertical and horizontal poles for construction scaffolding.
Advantages: The rectangular tube is correctly positioned during splicing (not easy to rotate), and the hollow structure is convenient for threading (such as the safety protection net fixing rope of scaffolding). At the same time, it is more than 50% lighter than solid square steel, making it easy to transport and install.
2. Bridge and traffic engineering field
Bridge auxiliary structures: load-bearing columns for guardrails of small pedestrian overpasses, support frames for bridge maintenance platforms, and crash barrier skeletons for cross sea bridges.
Advantages: The rectangular tube has excellent impact resistance (not easily deformed under lateral loads), and the hollow structure can be equipped with anti-corrosion coating, which is suitable for outdoor and humid environments of bridges (such as salt spray corrosion of coastal bridges).
Rail transit facilities: platform screen door support frames for subway stations, auxiliary load-bearing brackets for light rail tracks.
Advantages: The rectangular tube has a regular cross-section, making it easy to correctly connect with the screen door glass and track connectors. At the same time, its lightweight characteristics reduce the load-bearing pressure on the station ceiling or track foundation.
2、 Framework and bracket construction: The core function is to "shape and support equipment/components"
The "regular cross-section" and "ease of splicing" of rectangular tubes make them the core frame of various equipment, furniture, and instruments, mainly used to fix the position of components, bear the weight of equipment, and ensure the overall stability of the frame.
1. Mechanical and equipment manufacturing field
Industrial equipment framework: the base frame of CNC machine tools, the conveyor frame of automated production lines (such as the side bracket of belt conveyors), and the protective fence frame of robot workstations.
Advantages: The flat side of the rectangular tube is convenient for installing accessories such as motors, sensors, and protective plates (can be directly drilled and fixed without the need for processing irregular interfaces), and has good anti vibration performance (the frame is not easily resonant during equipment operation).
Agriculture and engineering machinery: cab frames for agricultural harvesters, armrest brackets for small loaders, and suspension frames for agricultural machinery.
Advantages: The hollow structure of the rectangular tube can reduce weight (improve mechanical maneuverability), and the wall thickness can be customized according to load requirements (such as using thick walled tubes for load-bearing parts and thin-walled tubes for non load-bearing parts), balancing cost and strength.
2. Home and office areas
Furniture frame: The armrest and base frame of the metal sofa, the support legs of the office desk, and the metal hanging rod of the wardrobe (square cross-section can prevent the hanging rod from rotating).
Advantages: The rectangular tube has a simple shape and can be rust proofed and aesthetically pleasing through spraying and galvanizing treatment. The hollow structure is lighter than solid square steel, making it easier to move furniture; The hanging rod with a square cross-section can also prevent the clothes hanger from sliding.
Display and storage facilities: columns and beams for supermarket shelves, support frames for exhibition booths, and layer supports for heavy-duty shelves in warehouses.
Advantages: The cross-sectional dimensions of rectangular pipes are standardized (such as 50 × 30mm, 80 × 40mm), which can be quickly assembled into shelves of different lengths and heights. Moreover, when multi-layer shelves are load-bearing, rectangular pipes have excellent shear resistance (the load on the shelves is not easy to cause deformation of the crossbeam).
3、 Fluid transport: The core function is to transport liquids/gases while also considering structural adaptation
The hollow channel of a rectangular tube can be used to transport fluids, and the rectangular cross-section can adapt to "narrow spaces" or "specific flow requirements", making up for the shortcomings of circular tubes in space utilization. It is mainly used in low-pressure and low-speed fluid scenarios.
1. Water supply and drainage and HVAC field
Indoor water supply and drainage pipes in buildings: concealed drainage pipes in bathrooms and kitchens (such as rectangular drainage pipes installed on walls), as well as condensate pipes in air conditioning systems.
Advantages: Rectangular pipes can be installed under walls or floors, saving space (such as in low rise residential buildings, circular pipes will protrude significantly, and rectangular pipes can be hidden in ceilings or wall grooves), and the inner wall is smooth and not easy to accumulate dirt, with low drainage resistance.
Industrial cooling water pipes: cooling circulation water pipes for small mechanical equipment such as machine tools and motors, as well as condensate water delivery pipes for cold storage.
Advantages: The flat outer wall of the rectangular tube is easy to fit with the cooling surface of the cooling equipment (such as the cooling tube of the motor housing, which can be directly welded to the equipment surface to improve heat dissipation efficiency), and the hollow channel can meet the cooling water flow rate requirements of low pressure (≤ 1.0MPa).
2. Ventilation and exhaust field
Indoor ventilation ducts: branch pipes for fresh air systems in office buildings and shopping malls (such as rectangular ventilation ducts in suspended ceilings), as well as exhaust pipes for kitchens.
Advantages: The cross-section of rectangular ducts can be customized according to the height and width of the ceiling (such as narrow height sections that are suitable for ceiling sandwich spaces), and when multiple rectangular ducts are installed in parallel, the space utilization rate is more than 30% higher than that of circular ducts, reducing the height occupied by the ceiling; At the same time, the interface of rectangular ducts is easier to seal, reducing air leakage rate.
Industrial exhaust pipes: dust exhaust branch pipes for small workshops, harmful gas exhaust pipes for laboratories.
Advantages: The inner wall of the rectangular tube has no dead corners, making it easy to clean in the later stage (such as dust pipes that are prone to dust accumulation, rectangular cross-sections can be manually or mechanically wiped off the inner wall), and it is more convenient to connect with the square interface of exhaust equipment (such as fans and dust collectors) without the need for variable diameter joints.
4、 Decoration and protection: The core function is "beautiful appearance, isolation and protection"
The regular cross-section and processability (such as cutting, bending, and spraying) of rectangular tubes make them a choice for decorative and protective components, mainly used to enhance scene aesthetics or achieve safe isolation.
1. In the field of decoration and interior design
Indoor and outdoor decorative styles: metal decorative frames in the atrium of shopping malls, corridor frames for outdoor landscapes (such as rectangular flower racks in parks), decorative lines on the exterior facade of buildings (such as waistlines and window frames).
Advantages: Rectangular pipes can be welded into geometric shapes (such as grids, diamonds), and the surface can be treated with galvanizing, spraying, fluorocarbon paint, etc. (colors available, such as black, silver, wood grain), balancing aesthetics and rust prevention; Hollow structures can also reduce the weight of decorative components and lower installation difficulty.
Identification and advertising carriers: the frame of outdoor billboards, the support frame of subway station signs, and the metal keel of store signs.
Advantages: The flat side of the rectangular tube is convenient for pasting advertising fabrics and identification panels (without additional reinforcement), and the frame strength is sufficient to support the weight of the billboard (such as not easily deformed in outdoor windy environments). At the same time, the lightweight feature reduces damage to the wall or floor during installation.
2. Protection and isolation field
Safety guardrails and fences: metal guardrails for factory walls, parking lot dividers, and protective railings for balconies (especially for children's balconies, rectangular pipes without sharp edges provide higher safety).
Advantages: The cross-section of the rectangular tube is flat, and the surface of the guardrail after splicing is smooth (to avoid scratches), and the wall thickness can be adjusted according to protection needs (such as using thick walled tubes for factory guardrails to prevent impact, and using thin-walled tubes for balcony guardrails to balance safety and aesthetics); At the same time, the spacing between rectangular pipes is easy to control and can meet safety regulations (such as balcony guardrails with a spacing of ≤ 110mm to prevent children from drilling out).
Equipment protective cover: safety protective cover for machine tools, dust cover frame for motors, and maintenance door frame for automation equipment.
Advantages: Rectangular tubes can be welded into closed or semi closed frames, and then combined with panels such as steel plates and acrylic plates to form protective covers; The hollow structure facilitates the installation of door locks, hinges, and other accessories within the frame, and is lightweight overall, making it easy to open and close the protective cover.
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