Introduction and specifications of Q390 steel
Q390 steel is a kind of Chinese low-alloy high-strength structural steel steel, the yield strength is 390 MPa, the parameters are tested with 16mm diameter steel bars or steel plates, the tensile strength is from 470-630 Mpa, the material density is 7.85 g/cm3. According to GB/T 1591-2018, Q390 has 3 quality levels: Q390B, Q390C, Q390D.
The characters and uses of Q390 are similar to those of Q345 and Q355.
Table 1, Chemical Composition of Q355 Steel
(GB/T 1591-2008)
| Steel Grade | Quality level | C% (≤) | % of Si (≤) | Mn (≤) | P(≤) | S (≤) | Nb (≤) | V (≤) | Ti (≤) | Cr (≤) | Ni (≤) | Cu (≤) | N (≤) | Mo (≤) | B (≤) | Also (≥) |
| Q390 | Q390A | 0.20 | 0.50 | 1.70 | 0.035 | 0.035 | 0.07 | 0.20 | 0.20 | 0:30 | 0.50 | 0:30 | 0.015 | 0.10 | – | – |
| Q390B | 0.035 | 0.035 | – | |||||||||||||
| Q390C | 0.030 | 0.030 | 0.015 | |||||||||||||
| Q390D | 0.030 | 0.025 | 0.015 | |||||||||||||
| Q390E | 0.025 | 0.020 | 0.015 |
(GB/T 1591-2018)
| Steel Grade | Quality level | C% (≤) | Si (≤) | Mn (≤) | P(≤) | S (≤) | Nb (≤) | V (≤) | Ti (≤) | Cr (≤) | Ni (≤) | Cu (≤) | N (≤) | Mo (≤) | B (≤) |
| Q390 | Q390B | 0.20 | 0.55 | 1.70 | 0.035 | 0.035 | 0.05 | 0.13 | 0.05 | 0:30 | 0.50 | 0.40 | 0.015 | 0.10 | – |
| Q390C | 0.030 | 0.030 | |||||||||||||
| Q390D | 0.025 | 0.025 |
Table 2, Carbon Equivalent (CEV)
steel delivered in hot-rolled state (based on casting analysis)
| CEV (mass fraction ≤%); Nominal thickness or diameter Ø | ||||||
| Steel Grade | Quality grade | ≤ 30 | 30 < Ø ≤ 63 | 63 < Ø ≤ 150 | 150 <Ø ≤ 250 | 250 <Ø ≤ 400 |
| Q390 | Q390B | 0.45 (CEV) | 0.47 | 0.48 | – | – |
| Q390C | ||||||
| Q390D | ||||||
Table 3, Mechanical Properties Q390 (hot rolled)
| Thickness or Diameter. (Ø) mm; Yield strength (≥N/mm2) | ||||||||||
| Steel Grade | Quality | 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 |
| Q390 | Q390B | 390 | 380 | 360 | 340 | 340 | 320 | – | – | – |
| Q390C | ||||||||||
| Q390D | ||||||||||
| Dia. (Ø) mm; Tensile strength (N/mm2) | |||||
| Steel Grade | Quality level | Ø≤100 | 100 <Ø ≤ 150 | 150 <Ø ≤ 250 | 250 <Ø ≤ 400 |
| Q390 | Q390B | 490 – 650 | 470 – 620 | – | – |
| Q390C | |||||
| Q390D | |||||
Table 4, Q390 Steel Elongation
| Dia. (Ø) mm; Stretching (%) | |||||||
| Steel Grade | Sample direction | Ø≤40 | 40 <Ø ≤ 63 | 63 <Ø ≤ 100 | 100 <Ø ≤ 150 | 150 <Ø ≤ 200 | 250 <Ø ≤ 400 |
| Q390 | Horizontal | 20 | 19 | 19 | 18 | – | – |
| Vertical | 21 | 20 | 20 | 19 | – | – | |
