Carbon steel square tube is a common metal profile，Widely used in architecture、Machinery manufacturing、car、Furniture and other fields。The following is a comprehensive introduction to carbon steel square tubes：
one、definition
Carbon steel square tube is a type of material made from carbon structural steel，Square steel pipes processed through cold bending or hot rolling processes。Its cross-section is square，F(xiàn)our sides of equal length and perpendicular，Has good mechanical and processing properties。
two、classification
Classified by production process：
Hot rolled square tube：Produced through hot rolling process，Suitable for large-sized and thick walled square tubes。
Cold formed square tube：Produced through cold bending process，Suitable for small-sized and thin-walled square tubes。
Classified by Material：
Ordinary carbon steel square tube：in compliance withQ235、Q345class，Has good weldability and processability。
High strength carbon steel square tube：in compliance withQ460class，Having higher strength and toughness。
Classified by surface treatment：
Hot dip galvanized square tube：Surface treated with hot-dip galvanizing，Has good corrosion resistance。
Cold galvanized square tube：Surface treated with cold galvanizing，The zinc layer is relatively thin，But the surface is smooth。
Spray painted square tube：Surface treated with spray paint，Suitable for decorative purposes。
bare pipe：Untreated square tube，Suitable for internal structure or further processing。
three、Production process
hot-rolling process：
Heat the steel billet to1100℃ - 1250℃，Make it reach a state of good plasticity。
Through multiple passes of rolling，Gradually forming the shape of a square tube。
Straighten and cut to length after cooling。
Cold bending process：
Select suitable steel strips or plates as raw materials。
Through cold bending forming unit，Bend the raw material into a square cross-section。
Adopting high-frequency welding or submerged arc welding technology，Ensure weld quality。
Finally, perform straightening、Cut to length and surface treatment。
four、Performance characteristics
mechanical property：
tensile strength：The tensile strength of ordinary carbon steel square tubes is generally in the range of370 - 500MPabetween，The tensile strength of high-strength carbon steel square tube can reach500 - 600MPa。
yield strength：The yield strength of ordinary carbon steel square tube is about235 - 345MPa，The yield strength of high-strength carbon steel square tube can reach345 - 460MPa。
Elongation rate：Usually in16% - 22%between，Has good plastic deformation ability。
processability：
weldability：Carbon steel square tube has good welding performance，Suitable for multiple welding methods。
Cutting ability：Easy to cut and process，Suitable for various mechanical processing techniques。
FLEXIBILITY：Has good bending performance，Capable of meeting complex structural requirements。
Surface Treatment：
CGL：A layer of zinc is formed on the surface，Has good corrosion resistance。
cold galvanizing：The zinc layer is relatively thin，But the surface is smooth，Suitable for decorative purposes。
spray painting：You can choose different colors and coatings according to your needs，Enhance aesthetics。
five、application area
Construction field：
Steel structure building：Used for beams、column、Framework and other structural components。
Architectural decoration：Used for railings、handrail、Decorative components such as door and window frames。
Machinery manufacturing：
Equipment framework：A framework used for manufacturing mechanical equipment、Bracket, etc。
Transmission components：Used for manufacturing transmission shafts、Gearbox and other components。
automobile making：
Body structure：Used for automotive chassis、Body frame and other components。
components and parts：Supporting components used for manufacturing automobiles、Connectors, etc。
Furniture manufacturing：
Table and chair frame：Used for manufacturing table legs、Chair frame and other components。
Decorative components：Decorative strips used for manufacturing furniture、Bracket, etc。
power engineering：
Power tower：Main materials used for manufacturing power tower frames、Components such as crossbeams。
Power distribution equipment：Bracket used for manufacturing distribution equipment、Shell and other components。
six、Purchase precautions
material selection：
Select appropriate materials based on usage requirements。Ordinary carbon steel square tube（in compliance withQ235）Suitable for general use，High strength carbon steel square tube（in compliance withQ345）Suitable for occasions with high load-bearing requirements。
dimensional accuracy：
Check if the size of the square tube meets the standard requirements，Including side length、wall thickness、Length, etc。
SURFACE QUALITY：
Check for cracks on the surface、scratch、Defects such as oxide skin。The zinc layer of hot-dip galvanized square tube should be uniform，No missing plating phenomenon。
mechanical property：
Request suppliers to provide mechanical performance testing reports，Ensure that the product meets the standard requirements。
Brand and Supplier：
Choose well-known brands or reputable suppliers，Ensure product quality and after-sales service。
seven、Standards and Quality Control
The production and acceptance of carbon steel square tubes should comply with the relevant national standards。Common standards include：
GB/T 6728-2017《Welded square tube》：The size of welded square tubes is specified、public errand、Requirements for mechanical properties, etc。
GB/T 8162-2018《Seamless Square Tube》：Established technical requirements and inspection methods for seamless square tubes。
eight、summarize
Carbon steel square tube due to its excellent mechanical properties、Processing performance and wide application fields，Becoming an indispensable and important material in modern industry and construction fields。Understand its production process、Performance characteristics、Application areas and key points for selection，Helps to better select and use the material。
