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

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I beam made from Q345 steel
I beam made from Q345 steel

Q345 Steel Properties and Introduction

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. 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”, which means Yield Point, “345” is the minimum value of yield strength 345 MPa for steel thickness ≤16mm.

Datasheet and Specification

For datasheet and specification, please see the tables below.

Table-1, Chemical Composition of Q345 Steel

Chemical Composition Content (≤%)≥%
Steel GradeQuality GradeCSiMnPSNbVTiCrNiCuNMoBAls
Q345Q345A0.200.501.700.0350.0350.070.150.200.300.500.300.0120.10
Q345B0.0350.035
Q345C0.0300.0300.015
Q345D0.180.0300.025
Q345E0.0250.020

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%.

Table-2, Q345 Mechanical Properties

Mechanical Properties: Yield Strength (≥ N/mm2)
Steel GradeQuality GradeØ ≤1616 < Ø ≤ 4040 < Ø ≤ 6363 < Ø ≤ 8080 < Ø ≤ 100100 < Ø ≤ 150150 < Ø ≤ 200200 < Ø ≤ 250250 < Ø ≤ 400
Q345Q345A≥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)
GradeQuality LevelØ ≤ 4040 < Ø ≤ 6363 < Ø ≤ 8080 < Ø ≤ 100100 < Ø ≤ 150150 < Ø ≤ 250250 < Ø ≤ 400
Q345Q345A470 – 630470 – 630470 – 630470 – 630450 – 600450 – 600
Q345B
Q345C
Q345D450 – 600
Q345E
Ø mm, Elongation (≥%)
GradeQuality LevelØ ≤4040 < Ø ≤ 6363 < Ø ≤ 100100 < Ø ≤ 150150 < Ø ≤ 250250 < Ø ≤ 400
Q345Q345A≥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).

QualityTemperature, ℃12-150 (mm)150<t≤250 (mm)250<t≤400 (mm)
Q345B20≥34J≥27J
Q345C0
Q345D-2027J
Q345E-40

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”.

Q345 Equivalent
ChinaUSAGermanyJapaneseISO
StandardGradeStandardGradeStandardGrade (steel number)StandardGradeStandardGrade
GB/T 1591 – 2008 (Year)Q345AASTM A529/A529M;
ASTM A572/A572M;
ASTM A588/A588M;
ASTM A678/A678M;
ASTM A808/A808M
Grade 50;
Grade 50;
Grade B;
Grade D;
A808M
 JIS G3135SPFC590ISO 630-2S355C, S355D (S355)
GB/T 1591 – 2008Q345BDittoDittoDIN EN 10025-2;
DIN 17100
S355, S355JR (1.0045),
E355 (1.0060);
St52-3
JIS G3135SPFC 590ISO 630-2S355C, S355D (S355)
GB/T1591 – 2008Q345CDittoDittoDIN EN 10025-2;
DIN 17100
S355J0 (1.0553),
E335 (1.0060);
St52-3
JIS G 3135SPFC590ISO 630-2S355D (S355)
GB/T 1591 – 2008Q345DASTM A656/A656M;
ASTM A529/A529M
Type 7;
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 3135SPFC590ISO 630-2S355D (S355)
GB/T 1591 – 2008Q345EASTM A656/A656M;
ASTM A529/A529M
Type 7;
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 G3135SPFC 590

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

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