What is rectangular tube?

What is rectangular tube?

Rectangular tube, also known as rectangular hollow section (RHS) or rectangular steel tube, is a metal profile with a hollow rectangular cross-section. Due to its strength and versatility, it is widely used in construction, engineering and manufacturing applications.
Rectangular tubes are made by bending or welding flat pieces of steel or aluminum into a rectangular shape, creating a tube with a hollow interior. These tubes are available in various sizes, thicknesses and lengths to suit different applications. The hollow interior makes them lighter than solid steel bars or beams while maintaining similar strength and load-bearing capacity.
Rectangular tubes are commonly used in building structures, machinery and equipment components, the automotive industry, and various construction applications. They are valued for their durability, strength, and resistance to bending and torsion, which makes them essential in many engineering projects.

Classification of rectangular tubes

Classification of rectangular tubes: steel tubes are divided into seamless steel tubes and welded steel tubes (seamed tubes), hot-rolled seamless square tubes, cold-drawn seamless square tubes, extruded seamless square tubes, and welded square tubes.
Among them, the welded square tube is divided into:
1. According to the process - arc welded square tube, resistance welded square tube (high frequency, low frequency), gas welded square tube, furnace welded square tube;
2. According to the weld seam - straight seam welded square pipe, spiral welded square pipe.

The use of rectangular tube

Rectangular tubes have a wide range of applications in various industries due to their versatility, strength and structural integrity. Some common uses for rectangular tubes include:

1. Architecture and Construction:
Structural Support: Rectangular tubes are used in building frames, columns and trusses to provide structural support in construction projects.
Architectural Design: They are used in the architectural design of decorative elements, facades and interior structures.
Fences and Railings: Rectangular tubes are used in fences, railings and handrails for their strength and durability.
Scaffolding: Rectangular tubes are used to construct scaffolding structures on construction sites.
2. Industry and Manufacturing:
Machinery and Equipment: Rectangular tubes are used in the manufacture of machine frames and components due to their strength and load-bearing capacity.
Conveyor Systems: They are used in conveyor systems for material handling in industries.
Storage Systems: Rectangular tubes are used to construct racks and racks for storage purposes.
Automotive: In the automotive industry, they are used in the manufacture of chassis and other structural components.

3. Transportation:

Truck and Trailer Frames: Rectangular tubes are used in the construction of truck and trailer frames for their strength and durability.
Railings: Used as railings and barriers in various modes of transportation.
4. Infrastructure:
Bridges and Overpasses: Rectangular tubes are used in the construction of bridges and overpasses to provide structural support.
Sign Structures: They are used in the construction of structures that support road signs and signals.

5. Furniture and interior design:

Furniture: Rectangular tubes are used in the construction of furniture frames, providing both support and a modern aesthetic.
Interior Design: They are used in interior design elements such as partitions, decorative panels and staircases.
6. Energy and Utilities:
Solar panel installation: Rectangular tubes are used for solar panel mounting structures.
Transmission Tower: A transmission tower used in the construction of electric power lines.

7. Recreation and sports:

Playground Equipment: Rectangular tubes are used in the construction of playground equipment and structures.
Sports Equipment: They are used in the construction of goal posts and other sports-related structures.
8. Agriculture:
Greenhouse: Rectangular tubes are used to build the greenhouse frame.
Agricultural equipment: used to manufacture various agricultural equipment.
The use of rectangular tubes continues to expand as the industry innovates and finds new applications for these versatile structural elements. Their adaptability, strength, and ease of use make them a popular choice in a variety of fields.

How to identify rectangular tubes?

1. Fake and inferior rectangular tubes are prone to folding. Folds are various fold lines formed on the surface of rectangular tubes, and this defect often runs throughout the length of the product. The reason for folding is that shoddy manufacturers pursue high efficiency and the reduction is too large, resulting in ears. Folding will occur during the next rolling process. The folded product will crack after bending, and the strength of the steel will be greatly reduced.
2. Fake and inferior rectangular tubes often have pitted surfaces on the surface. Pockmarking is an irregular uneven defect on the steel surface caused by severe wear of the rolling groove. Since manufacturers of shoddy rectangular tubes pursue profits, groove rolling often exceeds the standard.
3. The surface of fake and inferior rectangular tubes is prone to scarring. There are two reasons: (1). The material of fake and inferior rectangular tubes is uneven and contains many impurities. (2). The guide equipment of fake and inferior manufacturers is simple and easy to stick to steel. These impurities

4. The surface of fake and inferior materials is prone to cracks because its raw material is adobe, which has many pores. The adobe is subject to thermal stress during the cooling process, causing cracks, and cracks appear after rolling.
5. Fake and inferior rectangular tubes are easy to scratch. The reason is that the equipment of the fake and inferior rectangular tube manufacturers is simple and easy to produce burrs and scratch the surface of the steel. Deep scratches reduce the strength of steel.
6. The fake and inferior rectangular tube has no metallic luster and is light red or there are two reasons: its blank is adobe. The rolling temperature of fake and inferior steel products is not standard. Their steel temperature is measured by visual inspection. In this way, rolling cannot be carried out according to the specified austenite area, and the performance of the steel will naturally not meet the standards.

7. The transverse ribs of fake and inferior rectangular tubes are thin and low, and they often appear to be underfilled. The reason is that the manufacturer has a large negative tolerance and the first few passes of the finished product are pressed.
8. The cross-section of the fake and inferior rectangular tube is oval. The reason is that in order to save materials, the manufacturer uses a larger reduction amount in the first two passes of the finished roller. The strength of this kind of rebar is greatly reduced, and it does not meet the requirements for the overall dimensions of the rebar. standard.
9. The composition of high-quality steel is uniform, the tonnage of the cold shear machine is high, and the end face of the cutting head is smooth and neat. However, due to poor material quality, the end face of the cutting head of fake and inferior materials often has meat loss, that is, it is uneven and has no metallic luster. And because the manufacturer’s products have fewer heads, big ears will appear at the head and tail.

10. The material of fake and inferior rectangular pipes contains many impurities, the density of steel is small, and the dimensions are out of tolerance. If there is no vernier caliper, it can be weighed and checked. For example, for rebar 20, the national standard stipulates that the maximum negative tolerance is 5%. When the fixed length is 9M, its theoretical weight of a single rod is 120 kg. Its minimum weight should be: 120 X (l-5%) = 114 kg , the actual weight of a single piece is smaller than 114 kilograms, which means it is % fake and inferior steel. Generally speaking, the effect of phase-integrated weighing will be better, mainly considering the issues of cumulative error and probability theory.
11. The inner diameter of fake and inferior rectangular tubes fluctuates greatly due to the following reasons: 1. Unstable steel temperature has Yin and Yang sides. 2. The composition of steel is uneven. 3. Due to the crude equipment and low foundation strength, the rolling mill bounces greatly. There will be large changes within the same week. Such uneven stress on the steel bars will easily lead to breakage.
12. The trademarks and printing of high-quality pipes are relatively standardized.
13. The distance between rectangular tubes with a diameter of 16 and above is above IM.
14. The longitudinal bars of shoddy steel rebar are often wavy.

Precautions for Rectangular Tubes

The utilization rate of Q345 seamless rectangular pipe is very high, but the general construction party will conduct an appearance inspection on the pipes, pipe fittings, rubber rings, etc. before construction, and abandon the use if any problems are found.

1. Clean the nozzle of Q345 seamless rectangular pipe: remove and scrub all the sundries in the socket.
2. Clean the apron and install the apron: wipe off the adhesive on the apron, bend the apron into a "plum blossom" or 8-shaped shape and put it into the socket groove, and press it along the entire apron by hand, or Hit it firmly with a rubber hammer to ensure that all parts of the rubber ring are not warped or twisted, and are evenly stuck in the groove.
3. Brush the lubricant on the outer surface of the socket and the rubber ring: evenly paint the lubricant on the inner surface of the installed rubber ring of the socket, and when brushing the lubricant on the outer surface of the socket, wipe the socket parts other than the socket line Brush all over.
4. Tube down: The Q345 seamless rectangular tube should be lowered to the bottom of the tank according to the requirements of the tube, usually by manual or mechanical tube down method.
5. Install machinery and equipment: Install the prepared machinery and equipment in place, and be careful not to re-contaminate the cleaned Q345 seamless rectangular pipe during installation.
6. Push the Q345 seamless rectangular tube to insert it into the socket: during installation, it is more labor-saving and smooth to insert the socket into the socket. First put the socket into the socket and press the socket on the rubber ring in the socket, connect the wire rope and the rewinding chain, and tighten the rewinding chain; until the socket is fully inserted into the socket, there should be a gap of about 2mm between the socket and the socket , and ensure that the distance from the outer edge of the socket to the apron is consistent.

During the installation process, the axis lines of the fixed tube and the moving tube should be in a straight line, otherwise the rubber ring will be easily pushed out, which will affect the quality and speed of the installation. The Q345 seamless rectangular tube should be installed flat, and the Q345 seamless rectangular tube should be in a straight line. Be careful when there is an inclination angle. Align the interface connecting the Q345 seamless rectangular tube to the socket. If the insertion resistance is too large, do not insert it forcibly to prevent the rubber ring from twisting. Vegetable oil is suitable for the lubricating oil of the rubber ring; in cold winter, the rubber ring can be preheated with hot water to reduce the hardness and install it quickly.