Q355 Steel: Q355B, Q355C, Q355D
Q355 steel is a low-alloy, high-strength structural steel commonly used in China, which has replaced Q345. The material has a minimum yield strength of 355 MPa (51 ksi) and a tensile strength of 470-630 Mpa (68-91 ksi). According to GB/T 1591 -2018, Q355 has 3 types of steel: Q355AR, Q355M and Q355N, and these types of steel are indicated by the suffix letters B, C, D, E, F for quality grades.
Q355 : Q355B, Q355C and Q355D.
Q355M : Q355MB, Q355MC, Q355MD, Q355ME, Q355MF
Q355N : Q355NB, Q355NC, Q355ND, Q355NE, Q355NF
Meaning (Designation)
- “Q” is the abbreviation of Chinese Pinyin: “Qufu”, which means Yield Force;
- “355” indicates the minimum yield strength of 355 MPa for steel diameter or thickness ≤16mm;
- “AR” refers to As-Rolled, the symbol may be omitted/removed when the delivery condition is hot rolled;
- “M” means thermomechanically laminated;
- “N” means Normalized or Normalized Rolled;
- B, C, D, E and F indicate quality grades.
Note: AR, M and N refer to delivery conditions.
Properties of Q355 steel
The tables below show the properties of the Q355 material, technical data sheet and specifications such as chemical composition and physical and mechanical properties.
Chemical Composition (hot rolled)
Chemical composition of hot rolled steel based on thermal analysis.
| Chemical Composition (Thermal Analysis), %, ≤ | ||||||||||
| Steel Grade | Quality grade | W | Yes | Mn | P | s | Cr | No | Ass | N |
| Q355 | Q355B | 0.24 | 0.55 | 1.6 | 0.035 | 0.035 | 0:30 | 0:30 | 0.40 | 0.012 |
| Q355C | 0.20 | 0.030 | 0.030 | 0.012 | ||||||
| Q355D | 0.20 | 0.025 | 0.025 | – | ||||||
Note: For quality grades C and D, carbon content (C)-
- C ≤0.20% when thickness/diameter ≤40mm (1.57 in.);
- C ≤0.22 when thickness/diameter. >40 mm (1.57 in.);
Standardized or standard rolled steel
| Chemical Composition (Heat Analysis), % | |||||||||||||||
| Steel Grade | Quality grade | C, ≤ | Yes, ≤ | Mn | P, ≤ | S, ≤ | Cr, ≤ | Ni, ≤ | Cu, ≤ | Mo, ≤ | N, ≤ | No. | V | You | Al, ≥ |
| Q355N | Q355NB | 0.20 | 0.5 | 0.90-1.65 | 0.035 | 0.035 | 0:30 | 0.50 | 0.40 | 0.10 | 0.015 | 0.005-0.05 | 0.01-0.12 | 0.006-0.05 | 0.015 |
| Q355NC | 0.20 | 0.030 | 0.030 | ||||||||||||
| Q355ND | 0.20 | 0.030 | 0.025 | ||||||||||||
| Q355NE | 0.18 | 0.025 | 0.020 | ||||||||||||
| Q355NF | 0.16 | 0.020 | 0.010 | ||||||||||||
Thermomechanically rolled steel
| Chemical Composition (Heat Analysis), % | |||||||||||||||
| Steel Grade | Quality grade | C, ≤ | Yes, ≤ | Mn, ≤ | P, ≤ | S, ≤ | Cr, ≤ | Ni, ≤ | Cu, ≤ | Mo, ≤ | N, ≤ | No. | V | You | Al, ≥ |
| Q355M | Q355MB | 0.14 | 0.5 | 1.60 | 0.035 | 0.035 | 0:30 | 0.50 | 0.40 | 0.10 | 0.015 | 0.01-0.05 | 0.01-0.10 | 0.006-0.05 | 0.015 |
| Q355MC | 0.030 | 0.030 | |||||||||||||
| Q355MD | 0.030 | 0.025 | |||||||||||||
| Q355ME | 0.025 | 0.020 | |||||||||||||
| Q355MF | 0.020 | 0.010 | |||||||||||||
Grades:
- For bars and sections, the P and S content can be 0.005% higher.
- For Ti content, it can be up to 0.20%.
Carbon Equivalent (CEV)
Based on casting analysis, the steel was delivered hot-rolled.
| CEV (mass fraction ≤%); Nominal thickness or diameter (d) | ||||||
| Steel Grade | Quality grade | ≤ 30 | 30 < d ≤ 63 | 63 < d ≤ 150 | 150 < d ≤ 250 | 250 < d ≤ 400 |
| Q355 | Q355B | 0.45 (CEV) | 0.47 | 0.47 | 0.49 | – |
| Q355C | – | |||||
| Q355D | 0.49 | |||||
Q355 Material Mechanical Properties
Grades:
- 1 MPa = 1 N/mm2
- 1 GPa = 1kN/mm2
The mechanical properties of Q355 steel are listed in the data sheet below, including yield strength, tensile strength and elongation, etc.
Yield strength
| Yield strength (≥ MPa), Thickness or Diameter. (d) millimeters | ||||||||||
| Steel Grade | Quality grade | d≤16 | 16< d ≤40 | 40 |
63 < d ≤ 80 | 80< d ≤ 100 | 100< d≤ 150 | 150 |
200 < d ≤ 250 | 250 < d ≤ 400 |
| Q355 | Q355B | 355 | 345 | 335 | 325 | 315 | 295 | 285 | 275 | – |
| Q355C | – | |||||||||
| Q355D | 265 | |||||||||
| Q355N | All | – | ||||||||
| Yield strength (≥ MPa), Thickness or Diameter. (d) millimeters | |||||||
| Steel Grade | Quality grade | d≤16 | 16< d ≤40 | 40 |
63 < d ≤ 80 | 80< d ≤ 100 | 100< d≤ 120 |
| Q355M | All | 355 | 345 | 335 | 325 | 325 | 320 |
Tensile strength
| Tensile strength, MPa; Dia. (d) millimeters | ||||
| Steel Grade | Quality grade | d≤100 | 100< d ≤250 | 250< d ≤400 |
| Q355 | Q355B | 470-630 | 450-600 | – |
| Q355C | – | |||
| Q355D | 450-600 | |||
| Q355N | All | – | ||
| Tensile strength, MPa; Dia. (d) millimeters | |||||
| Steel Grade | Quality grade | d≤40 | 40< d ≤63 | 63< d ≤100 | 100< d ≤120 |
| Q355M | All | 470-630 | 450-610 | 440-600 | 430-590 |
Stretching
| Stretching (%); Dia. (d)mm; (hot rolled) | ||||||
| Sample direction | d≤40 | 40< d ≤63 | 63< d ≤100 | 100< d ≤150 | 150< d≤ 200 | 250< d ≤400 |
| Transversal | 20 | 19 | 18 | 18 | 17 | 17 |
| Vertical | 22 | 21 | 20 | 18 | 17 | 17 |
Charpy Impact
Charpy impact test temperature (V-notch) and impact absorption energy (KV 2 /J).
| Quality grade | Temperature, °C (°F) | Longitudinal impact energy (J), ≥ | Transverse impact energy (J), ≥ |
| Q355B, Q355MB, Q355NB |
20 (68) | 34 | 27 |
| Q355C, Q355MC, Q355NC |
0 (32) | 34 | 27 |
| Q355D | -20 (-4) | 34 (Only for thickness ≥250mm) | 27 (for thickness ≥250 mm) |
| Q355ND, Q355MD |
20 (68) | 55 | 31 |
| 0 (32) | 47 | 27 | |
| -20 (-4) | 40 | 20 | |
| Q355NE, Q355ME |
20 (68) | 63 | 40 |
| 0 (32) | 55 | 34 | |
| -20 (-4) | 47 | 27 | |
| -40 (-40) | 31 | 20 | |
| Q355NF, Q355MF |
20 (68) | 63 | 40 |
| 0 (32) | 55 | 34 | |
| -20 (-4) | 47 | 27 | |
| -40 (-40) | 31 | 20 | |
| -60 (-76) | 27 | 16 |
Physical properties
Density: 7,850 kg/m3 (0.284 lb/in3)
Melting Point: 1450-1530°C (2640-2800°F)
Features and applications
Q355 steel has good mechanical properties, good weldability, hot and cold processing properties and corrosion resistance. It can be used to manufacture ships, boilers, pressure vessels, oil storage tanks, bridges, power plant equipment, lifting transport machines and other high-load welded structural parts.
Steel Equivalent Grade Q355
The equivalent material of Q355 carbon steel is listed in the table below, including European EN standard (German DIN EN, British BSI, French NF…), ISO, Canada CSA (Canadian Standards Association), Australian/New Zealand and Indian IS standard.
| China | ISO | European Union | Canada | Australia/New Zealand | Indian | ||||||
| Standard | Note | Standard | Note | Standard | Class (Material Number) | Standard | Degree – SI (Imperial) | Standard | Note | Standard | Note |
| GB/T 1591 -2018 | Q355B | ISO 630-2 | S355B | EN 10025-2 | S355, S355JR (1.0045) | CSA G40.20-13/G40.21-13 | 350W (50W); 345WM (50WM) |
AS/NZS 3679.1 | Note 350; 350L0; 350L15 |
It's 2062 | E350 (Fe 490) |
| Q355C | S355C | S355J0 (1.0553) | |||||||||
| Q355D | S355D | S355J2 (1.0577) | |||||||||
Related materials: Material Q235 (Q235A, Q235B, Q235C, Q235D) | S235JR (1.0038) | Material St52-3 (1.0570) | S235JRG2 | S235J0 (1.0114) | 1.0117 (S235J2) | S235JRC (EN 1.0122) | St37-2 (1.0037)
