Q345C Steel Properties and Introduction
Q345C 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 (datasheet tested with 16mm diameter steel bars or steel plates). According to GB/T 1591 – 2008, Q345 material has 5 quality grades: Q345A, Q345B, Q345C, Q345D and Q345E. “Q” is the first letter of Chinese Pinyin: “qu fu dian”, which means Yield Point, “345” is short for 345 MPa. For datasheet and specification, please see the tables below.
Q345 steel weldability, cold & hot workability and corrosion resistance are good. Widely used in bridges, ships, boilers, pressure vessels, petroleum storage tanks, lifting transport machinery and other high-load welded structural parts.
Table-1, Chemical Composition of Q345C Steel
|
|
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%.
Table-2, 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 |
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)
Q345 Equivalent |
China |
USA |
Germany |
Japanese |
France |
UK |
ISO |
Standard |
Grade |
Standard |
Grade |
Standard |
Grade (steel number) |
Standard |
Grade |
Standard |
Grade (steel number) |
Standard |
Grade (steel number) |
Standard |
Grade |
GB/T 1591 – 2008 (Year) |
Q345A |
ASTM A529/A529M;
ASTM A572/A572M;
ASTM A588/A588M;
ASTM A678/A678M;
ASTM A808/A808M |
Grade 50;
Grade 50;
Grade B;
Grade D;
A808M |
DIN EN 10025-2;
DIN 17100 |
S355JR (1.0045),
E355 (1.0060);
St52-3 |
JIS G3135 |
SPFC590 |
NF EN 10025-2 |
S355JR (1.0045),
E355 (1.0060); |
BS EN 10025-2 |
S355JR (1.0045),
E355 (1.0060); |
ISO 630-2 |
S355C, S355D (S355) |
GB/T 1591 – 2008 |
Q345B |
Ditto |
Ditto |
Ditto |
Ditto |
JIS G3135 |
SPFC 590 |
Ditto |
Ditto |
Ditto |
Ditto |
ISO 630-2 |
S355C, S355D (S355) |
GB/T1591 – 2008 |
Q345C |
Ditto |
Ditto |
DIN EN 10025-2;
DIN 17100 |
S355J0 (1.0553),
E335 (1.0060);
St52-3 |
JIS G 3135 |
SPFC590 |
NF EN 10025-2 |
S355JO (1.0553),
E335 (1.0060) |
BS EN 10025-2 |
S355JO (1.0553),
E335 (1.0060) |
ISO 630-2 |
S355D (S355) |
GB/T 1591 – 2008 |
Q345D |
ASTM 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 3135 |
SPFC590 |
NF EN 10025-2;
NF EN 10025: 1993 |
S355J0 (1.0553),
E335 (1.0060);
S355J2G3 (1.0570) |
BS EN 10025-2;
BS EN 10025: 1993 |
S355J0 (1.0553),
E335 (1.0060);
S355J2G3 (1.0570) |
ISO 630-2 |
S355D (S355) |
GB/T 1591 – 2008 |
Q345E |
ASTM 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 G3135 |
SPFC 590 |
NF EN 10025-2;
NF EN 10025: 1993 |
S355J2 (1.0553),
S355K2 (1.0596),
E335 (1.0060);
S355J2G4 (1.0577),
S355K2G3 (1.0595),
S355K2G4 (1.0596) |
BS EN 10025-2;
BS EN 10025: 1993 |
S355J2 (1.0553),
S355K2 (1.0596),
E335 (1.0060);
S355J2G4 (1.0577),
S355K2G3 (1.0595),
S355K2G4 (1.0596) |
|
|
Notes: Q345 steel has been replaced byQ355 in the latest version of GB standard “GB/T 1591 – 2018”, the previous version is “GB/T 1591 – 2008”.