• GBT6479 16MnQ345B Seamless steel tubes for high-pressure chemical fertilizer equipments

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”)
Khorgos port(Пограничный пункт “Хоргос”)
→East Asia, Uzbekistan,Kazakhstan,Kyrgyzstan…(Train)
Erlianhot port→Mongolia(Train and Truck)
Manchuria port→Russia(Train and Truck)
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) 150 250
Q345B 20 ≥34J ≥27J —
Q345C 0
Q345D -20 27J
Q345E -40

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