About Us
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.
News
In this column you can find the steel pipe related articles you need, including industry trends, product standards and materials, and some technical guidelines.
Services
Eastern Steel Manufacturing Co.,Ltd not only improve product production and sales services, but also provide additional value-added services. As long as you need, we can complete your specific needs together.
Facility
Eastern Steel Manufacturing Co.,Ltd not only improve product production and sales services, but also provide additional value-added services. As long as you need, we can complete your specific needs together.
Projects
Many years of large-scale project experience in various fields（Oil & Gas, Construction, Power Energy, Marine & Offshore, Water Treatment, Exploration & Drilling Services, Pipeline & Petrochemical etc.）, professional project team is responsible from receiving until the end of the project.
Rectangular tube, is the full form of RHS steel, 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.
Arc welded square tube, resistance welded square tube (high frequency, low frequency), gas welded square tube, furnace welded square tube;
Straight seam welded square pipe, spiral welded square pipe.
Rectangular tubes possess high resistance
to bending, compression, and torsion, enabling them to withstand significant
external forces.
The cross-sectional shape of rectangular
tubes provides them with good stability, making them suitable for use in
various complex environments.
The smooth inner wall of rectangular tubes
facilitates cutting, bending, welding, and other processing operations, making
it convenient for manufacturing various structural components.
Rectangular tubes allow for efficient
material utilization in structural design, reducing waste and lowering costs.
The main manufacturing methods for
rectangular tubes are welding and cold bending.
Welded rectangular tubes are made by
rolling steel plates and welding the edges, suitable for larger-sized tubes.
Cold-bent rectangular tubes are formed by
roll forming, resulting in a smoother surface and higher dimensional accuracy,
suitable for applications requiring high surface quality.
Both processes have their advantages and
disadvantages; welded tubes are less expensive, while cold-bent tubes exhibit
more uniform mechanical properties.
1. 20×40mm RHS
steel, generally 5-12 meters in length, wall thickness 1.2-3.0mm;
2. 30×50mm RHS
steel, generally 5-12 meters in length, wall thickness 1.5-3.5mm;
3. 40×60mm RHS
steel, generally 5-12 meters in length, wall thickness 1.5-4.0mm;
4. 50×80mm RHS
steel, generally 5-12 meters in length, wall thickness 2.0-5.0mm;
5. Other common RHS steel models include 50×100mm, 60×80mm, 60×120mm,
80×100mm, 100×150mm, etc.
CHS steel (round pipes) have better
torsional resistance, but are not as good as rectangular pipes in terms of
bending and compressive strength. The curved surface of round pipes requires
additional fasteners when connecting to other planar structures, while the
planar contact of rectangular pipes makes them easier to weld or bolt.
I-beams have strong vertical bending
resistance but poor lateral stability and occupy a large amount of space.
Rectangular tubes offer better space utilization and are suitable for compact
structural designs.
Angle steel is mainly used for reinforcement or connection, but its stability is insufficient when used alone. Rectangular tubes can independently bear larger loads and are suitable for more complex stress environments.
Railings: Used as railings and barriers in various modes of transportation.
20×40mm RHS steels are suitable for light steel structures, such as frames for factory buildings, warehouses, exhibition halls, etc.
30×50mm RHS steels are suitable for light bridge structures such as long-span bridges.
40×60mm RHS steels are suitable for structural materials used for supporting and reinforcing large buildings and machinery.
50×80mm RHS steels are suitable for steel frame structures for long-span buildings, exhibition halls, stadiums, etc.
Other common types of RHS steels have a wider range of applications, suitable for both large-scale projects such as buildings and bridges, and smaller projects such as prefabricated houses and furniture.
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:
Unstable steel temperature has Yin and Yang sides.
The composition of steel is uneven.
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.
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.
Rectangular tubes are a common building structural material widely used in construction, bridges, and machinery manufacturing. Different types of rectangular tubes have different specifications and applications, which can be selected according to the specific needs of the application scenario.
Read more: What is the difference between square tube and rectangular tube? or What is RHS steel used for?
E-mail: sales@eastern-steels.com
