Q345 steel: Q345A, Q345B, Q345C, Q345D and Q345E
Q345 steel is a Chinese standard high-strength low-alloy structural steel. The material has a minimum yield strength of 345 MPa (50 ksi) and tensile strength of 470-630 Mpa (68-91 ksi). It has better properties than Q235. According to GB/T 1591 – 2008, Q345 material has 5 quality grades: Q345A, Q345B, Q345C, Q345D and Q345E .
Meaning and Designation
- “Q” is the abbreviation for Pinyin: “Qu”, which means Yield Force;
- “345” indicates that the steel has a minimum yield strength value of 345 MPa for steel diameter/thickness ≤16 mm.
- A, B, C, D and E indicate the quality level.
Properties, technical sheet and specification
Q345, Q345A, Q345B, Q345C, Q345D and Q345E steel properties, data sheet and specifications are listed in the tables below, including chemical composition, physical and mechanical properties, etc.
Chemical composition
Chemical Composition Based on fusion analysis.
| Chemical composition (≤%) | ||||||||||||||||
| Steel Grade | Quality grade | W | Yes | Mn | P | s | Cr | No | Mo | Ass | You | N | No. | V | B | Al, ≥ |
| 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 content of profiles and bars can be increased by 0.005%, and the upper limit of Class A steel can be 0.0045%.
Q345 Material Mechanical Properties
The mechanical properties of Q345 material are listed in the table below, including yield strength, tensile strength and elongation.
| Yield strength MPa (ksi), ≥ | ||||||||||
| Steel Grade | Quality grade | t ≤16 | 16< t ≤ 40 | 40 < t ≤ 63 | 63 |
80 < t ≤ 100 | 100 < t ≤ 150 | 150 < t ≤ 200 | 200 < t ≤ 250 | 250 < t ≤ 400 |
| Q345 | Q345A | 345 (50) | 335 (49) | 325 (47) | 315 (46) | 305 (44) | 285 (41) | 275 (40) | 265 (38) | – |
| Q345B | ||||||||||
| Q345C | ||||||||||
| Q345D | 265 (38) | |||||||||
| Q345E | ||||||||||
Grades:
- t= Thickness or diameter (mm);
- 1 MPa = 1 N/mm2
| Tensile strength MPa (ksi) | |||||
| Note | Quality grade | t≤ 100 | 100< t ≤250 | 250 |
|
| Q345 | Q345A | 470-630 (68-91) | 450-600 (65-87) | – | |
| Q345B | |||||
| Q345C | |||||
| Q345D | 450-600 (65-87) | ||||
| Q345E | |||||
| Stretch (%, ≥) | |||||||
| Note | Quality grade | t≤40 | 40 < t ≤ 63 | 63 |
100 |
150 < t ≤ 250 | 250 < t ≤ 400 |
| Q345 | Q345A | 20 | 19 | 19 | 18 | 17 | – |
| Q345B | |||||||
| Q345C | 21 | 20 | 20 | 19 | 18 | ||
| Q345D | 17 | ||||||
| Q345E | |||||||
Charpy Impact
Charpy impact test temperature (V-notch) and impact absorption energy (KV 2 /J).
| Quality | Temperature, °C (°F) | 12≤t≤150 (mm) | 150 |
250 |
| Q345B | 20 (68) | ≥34J | ≥27J | – |
| Q345C | 0 (32) | |||
| Q345D | -20 (-4) | 27J | ||
| Q345E | -40 (-40) |
Physical properties
Density: 7.85 g/cm3 (0.284 lb/in3)
Melting Point: 1450-1530°C (2640-2800°F)
Forms
Q345 steel has high strength, excellent weldability, cold and hot workability and certain corrosion resistance. It is widely used in bridges, ships, boilers, pressure vessels, petroleum storage tanks, lifting transportation machines and other high-load welded structural parts.
Q345 steel equivalent
Q345 Steel: Q345A, Q345B, Q345C, Q345D, Q345E equivalent ASTM, European, German, British, French, Australian, Canadian, Japanese and Indian standard (for reference).
Notes: Q345 steel has been replaced by Q355 in the latest version of the GB standard “GB/T 1591 – 2018”, the previous version is “GB/T 1591 – 2008”.
| Q345 Low Alloy Structural Steel Equivalent | |||||||||||||||||||
| Chinese | USA | European | Australian | Canadian | Indian | Japanese | ISO | ||||||||||||
| Standard | Note | Standard | Standard | Grade (steel number) | Standard | Note | Standard | Grade: Imperial (SI) | Standard | Note | Standard | Note | Standard | Note | |||||
| GB/T 1591 – 2008 | Q345A | ASTM A529 Grade 50 [345] ; ASTM A572 Grade 50 [345]; ASTM A588; ASTM A678 Grade A |
|||||||||||||||||
| GBT 1591 – 2008 | Q345B | EN 10025-2; DIN 17100 |
S355, S355JR (1.0045), E355 (1.0060); St52-3 |
AS/NZS 3678 | 350 | CSA G40.20/G40.21 | 50W (350W) | It's 2062 | E350 | JIS G3135 | SPFC 590 | ISO 630-2 | S355C, S355D (S355) | ||||||
| GB1591 – 2008 | Q345C | EN 10025-2; DIN 17100 |
S355J0 (1.0553), E335 (1.0060); St52-3 |
AS/NZS 3678 | 350L0 | CSA G40.20/G40.21 | 50W(350W) | IS2062 | E 350 | JIS G 3135 | SPFC590 | ISO 630-2 | S355D | ||||||
| GB 1591 – 2008 | Q345D | ASTM A656 Grade 50 [345]; ASTM A529 Grade 50 [345] |
EN 10025-2; EN 10025: 1993; DIN 17100 |
S355J0 (1.0553), E335 (1.0060); S355J2G3 (1.0570); St52-3 |
AS/NZS 3678 | 350L20 | CSA G40.20/G40.21 | 50W (350W) | It's 2062 | E350 | JIS G 3135 | SPFC590 | ISO630-2 | S355D | |||||
| GBT 1591 – 2008 | Q345E | ASTM A656/A656M Grade 50 [345]; ASTM A529/A529M Grade 50 [345]; ASTM A808 |
EN 10025-2; EN 10025: 1993 |
S355J2 (1.0553), S355K2 (1.0596), S355J2G4 (1.0577), S355K2G3 (1.0595), S355K2G4 (1.0596) |
AS/NZS 3678 | 350L40 | CSA G40.20/G40.21 | 50W(350W) | JIS G3135 | SPFC 590 | |||||||||
Tags: Q345A steel, Q345B steel, Q345C steel, Q345D steel, Q345E steel
Related Material: SS400 Steel, SUJ2 Steel, 304 Stainless Steel
