Steel flat bars are versatile, rectangular-cross-section profiles made from carbon or alloy steel, featuring flat surfaces and precise thickness-width ratios. Produced via hot-rolling or cold-drawing, they offer exceptional dimensional accuracy and surface finish options like black, galvanized, or polished. Carbon steel grades (e.g., A36, Q235) provide cost-effective strength for structural framing, brackets, and general fabrication, while alloy steel variants (e.g., 4140, S355JR) enhance durability in high-stress applications. Widely used in construction (base plates, stair treads), machinery (shafts, spacers), and automotive (chassis components), these bars conform to ASTM, EN, or JIS standards. Their weldability, machinability, and adaptability to bending or punching make them ideal for custom projects, from industrial equipment to DIY frameworks.

Q235 steel is a widely used low-carbon structural steel in China, similar to ASTM A36 in the US and S235JR in Europe. It is known for its balanced properties, including good weldability, formability, and reasonable strength, making it suitable for a wide range of structural applications. Q235 steel's properties include a low carbon content, which aids in its good weldability and machinability. It has a minimum yield strength of 235 MPa (decreasing with thickness) and a tensile strength ranging from 370 to 500 MPa.

Q345 steel is a high-strength, low-alloy (HSLA) structural steel widely used in China for demanding construction and engineering applications. It is known for its superior strength, toughness, ductility, and good weldability, particularly suitable for projects requiring high load-bearing capacity and resilience to challenging conditions. The "Q" in Q345 denotes yield strength, while "345" indicates a yield strength of 345 MPa.

A36 steel flat bars, adhering to ASTM A36 / A36M-08 standards, are a popular choice for structural applications due to their versatile properties. As a low-carbon or mild steel, it offers a balanced combination of strength, ductility, and excellent weldability. This makes it suitable for a wide range of projects, particularly in construction, including building frames, bridges, and other infrastructure, as well as in manufacturing applications like machinery parts and fabrication. The low carbon content (typically 0.25%-0.29%) facilitates welding and machining, contributing to its ease of fabrication. A36 steel is known for its reliability and cost-effectiveness, making it a staple material in various industries.

A283 steel flat bars, adhering to ASTM A283/A283M and ASME SA283/SA283M standards, represent a category of low-to-intermediate tensile strength carbon steel. Characterized by moderate strength, good formability, and easy weldability, this material is a versatile choice for structural and general fabrication projects. Its low carbon content (typically 0.24%-0.29%) facilitates welding and machining. Commonly available in hot-rolled condition, A283 steel is utilized in diverse applications such as buildings, bridges, storage tanks, and industrial machinery. Grades C and D are particularly favored for their balanced properties in construction and fabrication.

A572 steel flat bars are a high-strength, low-alloy (HSLA) structural steel widely used in applications where a high strength-to-weight ratio and durability are crucial. Available in various grades (42, 50, 55, 60, and 65) based on their minimum yield strength, A572 is known for its excellent weldability, good formability, and machinability. These flat bars are commonly utilized in construction for bridges, buildings, and infrastructure, as well as in the manufacturing of heavy machinery, truck parts, and other components needing robust support. Its corrosion resistance makes it suitable for outdoor use, particularly in marine environments or areas with higher humidity.

S235 steel flat bars, compliant with the European standard EN 10025, are a readily weldable, non-alloy structural steel with a low carbon content. The "S" signifies structural steel, while the "235" denotes its minimum yield strength of 235 MPa at 16 mm thickness. S235 offers a favorable balance of strength, ductility, and good machinability. This versatility makes it a popular choice for diverse applications, including building frameworks, bridge construction, heavy machinery components, and automotive parts. S235 steel is commonly supplied in hot-rolled or normalized conditions and can be readily formed, punched, or welded. Its characteristics, including moderate corrosion resistance (often enhanced by galvanization), make it a cost-effective and reliable material for various structural and fabrication projects.

S275 steel flat bars, adhering to the European standard EN 10025, are a popular choice for structural and general engineering applications. Designated by its mechanical properties, the "S" signifies structural steel and the "275" indicates its minimum yield strength of 275 MPa for thicknesses up to 16mm. S275 is known for its excellent weldability, good formability, and machinability, making it easy to work with in various projects. These properties, coupled with its relatively low cost, make S275 a versatile option for construction frameworks, heavy machinery components, and automotive parts. While it has moderate corrosion resistance, coatings like galvanization can enhance its durability in outdoor environments.

S355 steel flat bars, conforming to the European standard EN 10025, are a high-strength, low-alloy (HSLA) structural steel commonly chosen for applications requiring superior strength and durability. The "S" denotes structural steel, and "355" indicates its minimum yield strength of 355 MPa for thicknesses up to 16mm. S355 is recognized for its excellent weldability, good formability, and toughness, especially at lower temperatures. It is widely used in heavy construction for bridges, buildings, offshore structures, and manufacturing of heavy machinery and wind turbines. Available in several subgrades based on impact energy resistance (e.g., S355JR, S355J0, S355J2), S355 flat bars are a cost-effective and versatile option for demanding structural projects.

SS400 steel flat bars, compliant with the Japanese Industrial Standard JIS G3101, are a widely used hot-rolled structural steel, formerly known as SS41. The "SS" denotes steel structure, and "400" refers to its minimum tensile strength of 400 MPa. Known for its good weldability, machinability, and affordability, SS400 is a versatile material frequently chosen for structural components in construction, bridges, civil engineering, and mechanical equipment. It offers a balance of strength and ductility and is often considered equivalent to ASTM A36 in the US and Q235 in China. However, it's important to note that while similar, specific requirements for elements like carbon, manganese, phosphorus, and sulfur may differ between standards.

SM490 steel flat bars, conforming to the Japanese Industrial Standard JIS G3106, are a type of hot-rolled structural steel highly valued for their high strength, toughness, and excellent weldability. SM490 is widely used in demanding applications such as bridges, buildings, ships, vehicles, and heavy machinery, particularly where robust welded structures are required. There are different grades within the SM490 family (A, B, C, YA, YB), with grades B and C offering improved toughness for low-temperature applications. SM490A, for example, is commonly used in the engineering and construction industries. Its properties are often considered comparable to ASTM A572 Grade 50 in the US and EN S355JR in Europe.

S25C steel flat bars, conforming to the Japanese Industrial Standard JIS G4051, are a popular carbon steel for machine structural use. Known for its balanced properties, S25C boasts good machinability, weldability, and moderate strength. Its low carbon content, typically between 0.22% and 0.28%, makes it relatively easy to work with in various fabrication processes. This versatility makes it a suitable choice for applications like gears, shafts, fasteners, pinions, and other machinery parts requiring high toughness and low stress. However, it's important to note that S25C is not inherently corrosion-resistant and may require surface coatings or rust inhibitors in corrosive environments.