S550 series steel can be divided into four grades such as S550Q, S550QL, S550QL1 grade, belonging to the European standard low 5261 alloy high strength steel EN 10025-6-2004.
Chemical composition % of steel S550Q (1.8904): EN 10025-6-2004:
| C | Si | Mn | Ni | P | S | Cr | Mo | V | N | Nb | Ti | Cu | Zr | B | CEV |
| max 0.2 | max 0.8 | max 1.7 | max 2 | max 0.025 | max 0.015 | max 1.5 | max 0.7 | max 0.12 | max 0.015 | max 0.06 | max 0.05 | max 0.5 | max 0.15 | max 0.005 | max 0.83 |
Mechanical properties of steel S550Q (1.8904):
| Nominal thickness (mm): | 3 - 100 | 100 - 150 |
| Rm - Tensile strength (MPa) | 640-820 | 590-770 |
| Nominal thickness (mm): | 3 - 50 | 50 - 100 | 100 - 150 |
| ReH - Minimum yield strength (MPa) | 550 | 530 | 490 |
| KV - Impact energy (J) longitud., | 0° 40 |
-20° 30 |
| A - Min. elongation Lo = 5,65 √ So (%) | 16 |
S550Q steel plate delivery state: quenched and tempered state delivery.S550Q steel plate can also be attached to the requirements of flaw detection standards, flaw detection grade requirements, Z-direction performance requirements, adding special alloying elements requirements, but needs to supply and demand sides to communicate, and specified in the contract. So it also says the S550Q steel plate is a tempered high-strength steel plate.
