Q345 Steel, Q345A Q345B Q345C Q345D Q345E Equivalent, Specification, Chemical Composition, Properties

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Q345 Steel Properties

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, it has better properties than Q235. According to GB/T 1591 – 2008, Q345 material 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.

Meaning & Designation

“Q” is the first letter of Chinese Pinyin: “qu fu dian”, that means Yield Point, “345” is the minimum value of yield strength 345 MPa for steel thickness ≤16mm.

Datasheet and Specification

Datasheet and specification are listed in the tables below, including chemical composition, machenical properties, etc.

Chemical Composition of Q345 Steel

Based on melting analysis.

Chemical Composition Content (≤%)
Steel Grade Quality Grade C Si Mn P S Cr Ni Mo Cu Ti N Nb V B Als, ≥
Q345 Q345A 0.20 0.50 1.70 0.035 0.035 0.30 0.50 0.10 0.30 0.20 0.012 0.07 0.15
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%.

Material Q345 Mechanical Properties

Mechanical Properties: Yield Strength (≥ MPa)
Steel Grade Quality Grade d ≤16 16< d ≤ 40 40 <d ≤ 63 63 <d≤ 80 80 < d ≤ 100 100 < d ≤ 150 150 < d ≤ 200 200 < d ≤ 250 250 < d ≤ 400
Q345 Q345A 345 335 325 315 305 285 275 265
Q345B
Q345C
Q345D 265
Q345E

Notes:

  • d= Thickness or wire diameter in mm;
  • 1 MPa = 1 N/mm2
Mechanical Properties: Tensile Strength (MPa)
Grade Quality Level d≤ 40 40 <d ≤ 63 63 <d ≤ 80 80 <d≤ 100 100 < d≤ 150 150 < d ≤ 250 250 < d ≤ 400
Q345 Q345A 470-630 470-630 470-630 470-630 450-600 450-600
Q345B
Q345C
Q345D 450 – 600
Q345E
d mm, Elongation (≥%)
Grade Quality Level d≤40 40 <d ≤ 63 63 < d≤ 100 100 <d≤ 150 150 < d ≤ 250 250 <d ≤ 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, °C (°F) 12-150 (mm) 150<t≤250 (mm) 250<t≤400 (mm)
Q345B 20 (68) ≥34J ≥27J
Q345C 0 (32)
Q345D -20 (-4) 27J
Q345E -40 (-40)

Material Q345 Equivalent

Q345 steel: Q345A, Q345B, Q345C, Q345D, Q345E equivalent to US ASTM, European Germany DIN, British BS, France NF, Japan JIS, and ISO Standard (For Reference).

Notes: Q345 steel has been replaced by Q355 in the latest version of GB standard “GB/T 1591 – 2018”, the previous version is “GB/T 1591 – 2008”.

Low Alloy Structural Steel Q345 Equivalent
China US Germany Japanese ISO
Standard Grade Standard Standard Grade (steel number) Standard Grade Standard Grade
GB/T 1591 – 2008 (Year) Q345A ASTM A529 Grade 50;
ASTM A572 Grade 50;
ASTM A588 Grade 50;
ASTM A678 Grade 50
JIS G3135 SPFC590 ISO 630-2 S355C, S355D (S355)
GB/T 1591 – 2008 Q345B DIN EN 10025-2;
DIN 17100
S355, S355JR (1.0045),
E355 (1.0060);
St52-3
JIS G3135 SPFC 590 ISO 630-2 S355C, S355D (S355)
GB1591 – 2008 Q345C DIN EN 10025-2;
DIN 17100
S355J0 (1.0553),
E335 (1.0060);
St52-3
JIS G 3135 SPFC590 ISO 630-2 S355D (S355)
GB 1591 – 2008 Q345D ASTM A656 Grade 50;
ASTM A529 Grade 50
DIN EN 10025-2;
DIN EN 10025: 1993;
DIN 17100
S355J0 (1.0553),
E335 (1.0060);
S355J2G3 (1.0570);
St52-3
JIS G 3135 SPFC590 ISO 630-2 S355D (S355)
GB/T 1591 – 2008 Q345E ASTM A656/A656M Grade 50;
ASTM A529/A529M Grade 50;
ASTM A808 Grade 50
DIN EN 10025-2;
DIN EN 10025: 1993
S355J2 (1.0553),
S355K2 (1.0596),
E335 (1.0060);
S355J2G4 (1.0577),
S355K2G3 (1.0595),
S355K2G4 (1.0596)
JIS G3135 SPFC 590

Tags: Q345A steel, Q345B steel, Q345C steel, Q345D steel, Q345E steel

Related material: SS400 Steel, SUJ2 Steel, 304 Stainless Steel

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2 Comments
  1. Fred says

    I sent an enquiry on this yesterday if the Q345 material can withstand caustic without corroding. We want to fabricate a tanker for transporting caustic on long distance.

    Kindly respond.

    Thanks

    1. World Material says

      Hi, Fred, so sorry that we don’t sell steel products.

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