◆ Standards
Q345 carbon steel | GB | ASTM | DIN | JIS | NF EN | BS EN | ISO |
Q345A | Gr.50 Gr.B Gr.C Gr.D Gr.A A808M | E335 | SPFC590 | E335 | E335 | HS355CC E355CC | |
Q345B | Gr.50 Gr.B Gr.C Gr.D Gr.A A808M | S335JR | SPFC590 | E335JR | E335JR | E355CC | |
Q345C | Gr.C Gr.D TyPe7 Gr.A A808M Gr.50 | S355JO | SPFC590 | S335JO | S335JO | E355DD | |
Q345D | TyPe7 Gr.50 | S355J2G3 S355J2G4 S355K2G3 S355K2G4 | SPFC590 | S355J2G3 S355J2G4 S355K2G3 S355K2G4 | S355J2G3 S355J2G4 S355K2G3 S355K2G4 | E355DD | |
Q345E | TyPe7 Gr.50 | S355NL S355ML | SPFC590 | S355NL S355ML | S355NL S355ML | E355E E355DD |
◆ Properties
Chemical properties
Grade and chemical composition of Q345 carbon steel (smelting analysis):
Q345 | quality level | C | Si | Mn | P | S | Nb | V | Ti | Cr | Ni | Cu | N | Mo | B | Als |
A | ≤0.20 | ≤0.50 | ≤1.70 | ≤0.035 | ≤0.035 | ≤0.07 | ≤0.15 | ≤0.20 | ≤0.30 | ≤0.50 | ≤0.30 | ≤0.012 | ≤0.10 | - | - | |
B | ≤0.035 | ≤0.035 | ||||||||||||||
C | ≤0.030 | ≤0.030 | ≥0.07 | |||||||||||||
D | ≤0.18 | ≤0.030 | ≤0.025 | |||||||||||||
E | ≤0.025 | ≤0.020 |
Carbon equivalent of Q345 carbon steel delivered in hot-rolled and controlled-rolled state :
Q345 carbon steel | Carbon Equivalent(CEV)/% | ||
Nominal Thickness or Diameter ≤63mm | Nominal Thickness or Diameter >63mm~250mm | Nominal Thickness >250mm | |
≤0.44 | ≤0.47 | ≤0.47 |
Carbon equivalent of Q345 hot rolled carbon steel coil delivered in normalized, normalized rolled, normalized plus tempered state :
Q345 hot rolled carbon steel coil | Carbon Equivalent(CEV)/% | ||
Nominal Thickness ≤63mm | Nominal Thickness >63mm~120mm | Nominal Thickness >120mm~250mm | |
≤0.45 | ≤0.48 | ≤0.48 |
The carbon equivalent of Q345 steel coil delivered in the state of thermomechanical rolling (TMCP) or thermomechanical rolling plus tempering :
Q345 steel coil | Carbon Equivalent(CEV)/% | ||
Nominal Thickness ≤63mm | Nominal Thickness >63mm~120mm | Nominal Thickness >120mm~150mm | |
≤0.44 | ≤0.45 | ≤0.45 |
Pcm value of Q345 carbon steel delivered in the state of thermomechanical rolling (TMCP) or thermomechanical rolling plus tempering :
Q345 carbon steel | Pcm/% |
≤0.20 |
Mechancal properties:
Q345 Carbon Steel | Quality Level | Yield strength at the following nominal thickness (diameter, side length)(ReL)/MPa | ||||||||
≤16mm | >16mm ~ 40mm | >40mm ~ 63mm | >63mm ~ 80mm | >80mm ~ 100mm | >100mm ~ 150mm | >150mm ~ 200mm | >200mm ~ 250mm | >250mm ~ 400mm | ||
A | ≥345 | ≥335 | ≥325 | ≥315 | ≥305 | ≥285 | ≥275 | ≥265 | - | |
B | ||||||||||
C | ||||||||||
D | ≥265 | |||||||||
E |
Q345 Steel Coil | Quality Level | Tensile strength at the following nominal thickness (diameter, side length)(Rm)/MPa | ||||||
≤40mm | >40mm ~ 63mm | >63mm ~ 80mm | >80mm ~ 100mm | >100mm ~ 150mm | >150mm ~ 250mm | >250mm ~ 400mm | ||
A | 470~630 | 470~630 | 470~630 | 470~630 | 450~600 | 450~600 | - | |
B | ||||||||
C | ||||||||
D | 450~600 | |||||||
E |
Q345 Hot Rolled Carbon Steel Coil | Quality Level | Elongation after break (A)/% | |||||
≤40mm | >40mm ~ 63mm | >63mm ~ 100mm | >100mm ~ 150mm | >150mm ~ 250mm | >250mm ~ 400mm | ||
A | ≥20 | ≥19 | ≥19 | ≥18 | ≥17 | - | |
B | |||||||
C | ≥21 | ≥20 | ≥20 | ≥19 | ≥18 | ||
D | ≥17 | ||||||
E |
Q345 Carbon Steel | Quality Level | Test temperature/℃ | Impact absorption energy (KV2)a*/J Nominal thickness (diameter, side length) | ||
12mm~150mm | >150mm~250mm | >250mm~400mm | |||
B | 20 | ≥34 | ≥27 | - | |
C | 0 | ||||
D | -20 | 27 | |||
E | -40 | ||||
a The impact test takes a longitudinal sample. |
Q345 Steel Coil | Specimen Direction | 180°bending test [d=centroid diameter, α=sample thickness (diameter)] | |
Flat material with a width of not less than 600mm, transverse specimen for tensile test. For flat materials, profiles and bars with a width less than 600mm, longitudinal samples shall be taken. | Steel thickness (diameter, side length) | ||
≤16mm | >16mm~100mm | ||
2α | 3α |
◆ Characteristic
Q345 steel coil is a low-alloy high-strength structural steel material, Q represents the yield strength of this steel, and the latter 345 represents the yield value, and it will increase with the thickness of Q345 hot rolled carbon steel coil. Its yield value decreases.
Q345 carbon steel has good comprehensive mechanical properties such as low temperature performance, plasticity and weldability, and can be used for various structural parts in cold environments below -40 °C.
◆ Industry&Application
Q345 hot rolled carbon steel coils are widely used in construction, bridges, vehicles, ships, pressure vessels and other industries.
In the state of hot rolling or normalizing, Q345 steel coils are mainly used to manufacture low and medium pressure vessels, oil tanks, cranes, mining machinery, power stations, bridges and other dynamic load-bearing structures, mechanical parts, building structures, and general metal structural parts.