Q345 steel is a Chinese GB standard low alloy high strength structural steel, material density is 7.85 g/cm3, tensile strength is 470-630 Mpa, and yield strength is 345 MPa. “Q” is the first letter of Chinese Pinyin: “qu fu dian”, which means Yield Point, “345” is the minimum value of yield strength 345 MPa for steel thickness ≤16mm. It has 5 quality grades: Q345A, Q345B, Q345C, Q345D and Q345E.
Q345 steel has good weldability, cold & hot workability and corrosion resistance. Widely used in bridges, ships, boilers, pressure vessels, petroleum storage tanks, lifting transport machinery and other high-load welded structural parts.
Specifications
Standard | GB/T 6479, GB/T 8162, GB/T 8163 |
Grade | Q345A, Q345B, Q345C, Q345D, Q345E |
OEM | Acceptable |
Outer Diameter(OD) | 1 1/2”-28”(38mm-720mm) |
Wall Thickness(WT) | 2.6mm-60mm |
Length | 5.8-16m or OEM |
Packing | PE,BE,Plastic cap or bundling |
Surface Treatmengt | Black paint,3LPE,3lPP,FBE…OEM |
Section Shape | Round |
Technique | Seamless hot rolled |
Application | Widely used in bridges, ships, boilers, pressure vessels, petroleum storage tanks, lifting transport machinery and other high-load welded structural parts. |
Sour service | No |
Place of Origin | China |
MOQ | 25 ton |
Transportation | 1.Sea port:Tianjin Xingang port,Qingdao port,Shanghai Luojing port →America,Europe,Africa,Middle East,India, Pakistan,Japan,Korea, Australia…(shipping) 2.Land port:Alataw pass port(Пограничный пункт “Алашанькоу”) |
Chemical Composition Content (≤%) | ≥% | |||||||||||||||
Steel Grade | Quality Grade | C | Si | Mn | P | S | Nb | V | Ti | Cr | Ni | Cu | N | Mo | B | Als |
Q345 | Q345A | 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 | – | – |
Q345B | 0.035 | 0.035 | ||||||||||||||
Q345C | 0.030 | 0.030 | 0.015 | |||||||||||||
Q345D | 0.18 | 0.030 | 0.025 | |||||||||||||
Q345E | 0.025 | 0.020 |
Notes: The P and S contents of profiles and bars can be increased by 0.005%, and the upper limit of Grade A steel can be 0.0045%.
Q345 Mechanical Properties
Mechanical Properties: Yield Strength (≥ N/mm2) | ||||||||||
Steel Grade | Quality Grade | Ø ≤16 | 16 < Ø ≤ 40 | 40 < Ø ≤ 63 | 63 < Ø ≤ 80 | 80 < Ø ≤ 100 | 100 < Ø ≤ 150 | 150 < Ø ≤ 200 | 200 < Ø ≤ 250 | 250 < Ø ≤ 400 |
Q345 | Q345A | ≥345 | ≥335 | ≥325 | ≥315 | ≥305 | ≥285 | ≥275 | ≥265 | – |
Q345B | ||||||||||
Q345C | ||||||||||
Q345D | ≥265 | |||||||||
Q345E |
Notes: Ø = Thickness or wire diameter in mm;
1 MPa = 1 N/mm2
Mechanical Properties: Tensile Strength (N/mm2) | ||||||||
Grade | Quality Level | Ø ≤ 40 | 40 < Ø ≤ 63 | 63 < Ø ≤ 80 | 80 < Ø ≤ 100 | 100 < Ø ≤ 150 | 150 < Ø ≤ 250 | 250 < Ø ≤ 400 |
Q345 | Q345A | 470 – 630 | 470 – 630 | 470 – 630 | 470 – 630 | 450 – 600 | 450 – 600 | – |
Q345B | ||||||||
Q345C | ||||||||
Q345D | 450 – 600 | |||||||
Q345E |
Ø mm, Elongation (≥%) | |||||||
Grade | Quality Level | Ø ≤40 | 40 < Ø ≤ 63 | 63 < Ø ≤ 100 | 100 < Ø ≤ 150 | 150 < Ø ≤ 250 | 250 < Ø ≤ 400 |
Q345 | Q345A | ≥20 | ≥19 | ≥19 | ≥18 | ≥17 | – |
Q345B | |||||||
Q345C | ≥21 | ≥20 | ≥20 | ≥19 | ≥18 | ||
Q345D | ≥17 | ||||||
Q345E |
Charpy Impact
Charpy (V-notch) impact test temperature and impact absorption energy (KV2/J), thickness (t).
Quality | Temperature, ℃ | 12-150 (mm) | 150250 | |
Q345B | 20 | ≥34J | ≥27J | — |
Q345C | 0 | |||
Q345D | -20 | 27J | ||
Q345E | -40 |