Square tubes are an indispensable form of steel usage, commonly employed in steel structures, structural facades, machinery manufacturing, construction materials, shipbuilding, airports, and liquid transportation. Square tubes are categorized into seamless and welded joints, with seamless tubes being formed by extruding round tubes without seams, suitable for liquid transmission. Welded square tubes are typically made by welding steel plates and are often used in steel structures, etc. Malleability refers to the ability of metal materials to slow down plastic deformation (deformation) under load without breaking. Hardness is the ability of metal materials to combine hardness and softness; too much steel makes it brittle, and too soft makes it non-malleable. In current square tube inspections, the commonly used method is the indentation hardness test, which measures the degree of indentation formed by squeezing the square tube. Now, cold-rolled square tubes have reached or even exceeded the level of welded square tubes in terms of corner dimensions, edge angles, and straightness for steel structure projects.
Square tubes are hollow, square-sectioned, lightweight, thin-walled steel pipes, also known as cold-formed steel shapes. The common material is Q235, which includes grades such as B, C, and D. Welded square tubes are based on hot-rolled or cold-rolled strip or coil of Q235, then formed by high-frequency welding, suitable only for general requirements. These tubes typically have better performance and stronger sealing properties; we usually use seamless round tubes, cold-rolled to form, compared to hot-rolled square tubes. Hot-rolled thick-walled square tubes are known for their increased wall thickness, with hardness values measured according to the degree of hardness testing. Common methods include Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC), and Vickers hardness (HV). It is well-known that metals have fatigue properties, such as when we repeatedly bend a piece of wire, it will break. Square tubes exhibit this characteristic as well. The fatigue discussed in terms of strength, ductility, and hardness are indicators of the mechanical properties of metals under static loads. In reality, solar panel supports, steel structural projects, and many machine parts operate under cyclic loads. After a certain period of use, they are all subject to testing, at which point the parts may fatigue. Therefore, regular safety inspections are still necessary.
Square tubes are an indispensable material in construction decoration, machinery manufacturing, steel structure projects, and glass curtain walls. They are also quite common in daily life, such as in security windows and railings. Proper use can yield unexpected effects, especially in the selection of square tube specifications and sizes, which is a crucial step. This is because it directly relates to safety hazards, such as cases of injury or death in construction due to broken protective railings. Therefore, one cannot be careless when choosing the specifications and sizes of square tubes.
Square tube applications
Rectangular tubes are used in construction, machinery manufacturing, steel construction projects, shipbuilding, solar power generation supports, steel structure engineering, power engineering, power plants, agricultural and chemical machinery, glass curtain walls, automotive undercarriages, airports, boiler construction, highway guardrails, building construction, pressure vessels, oil storage tanks, bridges, power station equipment, lifting and transportation machinery, and other welded structural components with high loads.
Strength refers to the material's ability to withstand failure under static load (such as appropriate plastic deformation or fracture) for Q195焊接方管. Since the form of load application can be tensile, compressive, bending, or shearing, strength is categorized into tensile strength, compressive strength, bending strength, and shearing strength, etc.
