Chemical Composition: Low carbon (0.06-0.12%), manganese (0.25-0.50%), with impurities controlled (S ≤0.045%, P ≤0.045%).
Mechanical Performance: Tensile strength 315-430 MPa, yield strength ≥195 MPa (hence "Q195"), elongation ≥33%—high ductility for bending/forming.
Typical Applications
Light frameworks (e.g., furniture, shelving, temporary structures).
Supporting brackets, edge reinforcements, or connectors in low-load scenarios.
DIY projects or small-scale fabrications due to easy cutting, welding, and bending.

Chemical Composition: Carbon (0.14-0.22%), manganese (0.30-0.65%), with impurity limits (S ≤0.050%, P ≤0.045%).
Mechanical Performance: Tensile strength 375-500 MPa, yield strength ≥235 MPa (the "Q235" designation), elongation ≥26%—good ductility for forming.
Typical Applications
General structural frameworks (e.g., building trusses, bridges, machinery supports).
Brackets, connectors, or reinforcements in medium-load structures.
Fabrication of shelves, racks, and industrial fixtures due to easy welding/cutting.

Chemical Composition: Carbon (0.28-0.38%), manganese (0.50-0.80%), with impurity controls (sulfur ≤0.050%, phosphorus ≤0.045%).
Mechanical Performance: Tensile strength 490-630 MPa, yield strength ≥275 MPa (the "Q275" designation), elongation ≥20%—adequate ductility for bending/forming.
Typical Applications
Structural components in medium-load scenarios: frames for heavy machinery, support beams in industrial buildings, or load-bearing brackets.
Fabrication of tools, fasteners, or parts requiring higher strength than Q235.

Chemical Composition: Ultra-low carbon (0.05-0.11%), manganese (≤0.40%), silicon (≤0.03%), with strict impurity control (S ≤0.035%, P ≤0.035%). The "F" denotes (rimmed steel), enhancing its softness.
Mechanical Performance: Tensile strength 295-410 MPa, yield strength ≥175 MPa, elongation ≥35%—among the highest ductility in carbon steels, enabling easy bending, stamping, or drawing.
Typical Applications
Cold-formed components: Channels used in lightweight frameworks, decorative structures, or precision parts requiring intricate shaping (e.g., automotive trim, electrical enclosures).
Low-load structural uses: Supports, guides, or rails in machinery where formability is critical and strength demands are low.
DIY or small-scale fabrications: Easy to cut, weld, or bend without specialized equipment.

Chemical Composition: Carbon (0.07-0.14%), manganese (0.35-0.65%), silicon (≤0.17%), with controlled impurities (S ≤0.035%, P ≤0.035%).
Mechanical Performance: Tensile strength 335-475 MPa, yield strength ≥205 MPa, elongation ≥31%—good ductility for bending, welding, and cold working.
Typical Applications
General structural frameworks: Supports, rails, or guides in machinery, construction, or automotive components.
Fabrication of brackets, frames, or channels for low to medium load-bearing scenarios.
Cold-formed parts requiring better strength than ultra-low carbon steels (e.g., 08F) while retaining formability.

Chemical Composition: Carbon (0.17-0.24%), manganese (0.35-0.65%), silicon (≤0.17%), with strict impurity controls (sulfur ≤0.035%, phosphorus ≤0.035%). Compared to lower-carbon steels like 10#, it has a slightly higher carbon content, enhancing strength.
Mechanical Performance: Tensile strength 410-550 MPa, yield strength ≥245 MPa, elongation ≥25%—retaining good ductility while offering higher strength than 10# steel.
Typical Applications
Medium-load structural components: Frames, supports, or rails in machinery, industrial equipment, and construction (e.g., conveyor systems, crane structures).
Fabrication of mechanical parts: Shafts, brackets, or channels requiring both formability and moderate load-bearing capacity.
Welded or machined components in automotive, shipbuilding, or hydraulic systems, where a balance of strength and processability is needed.

Chemical Composition: Carbon (C) 0.27 - 0.34%, manganese (Mn) 0.50 - 0.80%, silicon (Si) 0.17 - 0.37%, phosphorus (P) ≤0.035%, sulfur (S) ≤0.035%.
Mechanical Properties: Tensile strength σb (MPa) ≥490, yield strength σs (MPa) ≥295, elongation δ5 (%) ≥21, reduction of area ψ (%) ≥50, impact energy Akv (J) ≥63.
Application Fields: Widely used in building structures, bridge projects, mechanical manufacturing, automotive manufacturing and other fields. For example, it is used for the main and auxiliary structures of buildings such as beams, columns, and frames; in bridge construction, it is used for bridge beams, columns and bearing platforms; in the automotive manufacturing industry, it is used as one of the main materials for body structures.

Chemical Composition: According to GB/T 699 - 2015, the carbon (C) content is 0.52 - 0.60%, silicon (Si) 0.17 - 0.37%, manganese (Mn) 0.50 - 0.80%, sulfur (S) ≤0.035%, phosphorus (P) ≤0.035%, chromium (Cr) ≤0.25%, nickel (Ni) ≤0.30%, and copper (Cu) ≤0.25%.
Mechanical Properties: The tensile strength σb≥645MPa, the yield strength σs≥380MPa, the elongation δ5≥13%, the reduction of area ψ≥35%. The hardness of the untreated steel is ≤255HB, and that of the annealed steel is ≤217HB.
Application Fields: It is often used in the manufacture of parts that require higher strength and wear resistance, as well as parts with low dynamic load and impact load, such as gears, wheel rims, and flat springs. In the field of engineering construction, it can be used for I - beams in steel structures.

Chemical Composition: The carbon (C) content is 0.17 - 0.24%, silicon (Si) 0.17 - 0.37%, manganese (Mn) 0.70 - 1.00%, phosphorus (P) ≤0.035%, sulfur (S) ≤0.035%, chromium (Cr) ≤0.25%, nickel (Ni) ≤0.25%, and copper (Cu) ≤0.25%.
Mechanical Properties: The tensile strength is ≥450MPa, the yield strength is ≥275MPa, the elongation is ≥24%, the reduction of area is ≥50%, and the hardness in the un - heat - treated state is ≤197HB.
Application Fields: It is widely used in the construction field to manufacture structural components such as beams, columns and walls of houses, factories and warehouses; in the ship field, it is used for hull structural components, decks, bulkheads, etc.; it can also be used to produce vehicle floors, frames, carriages, etc. in the vehicle field.