Introduction to S550QL1 steel plate

S550QL1 is a special alloy steel, European standard trademark, divided into S550Q, S550QL and S550QL1; S550QL1 steel plate belongs to quenched and tempered high yield strength structural steel, S indicates structural steel, 550 indicates yield value, unit: MPa, Q indicates delivery conditions, and L1 indicates the minimum value specified for impact energy when the temperature is not lower than - 60℃. S550QL1 steel is a trademark in EN 10025-6. This specification stipulates that the minimum nominal thickness of the steel is 3mm and the maximum nominal thickness is ≤ 150mm.

S550QL1 steel plate heat treatment: quenching and tempering.

Smelting analysis and chemical composition of S550QL1 steel plate

Mechanical properties of S550QL1 steel plate
Thickness 3-50mm
ReH(MPa) ≥550
Rm(MPa) 640-820
A(%) ≥16
Akv (J) ≥ 30 longitudinal;
Transverse: Akv ≥ 27J

Thickness >50-100mm
ReH(MPa) ≥530
Rm(MPa) 640-820
A(%) ≥16
Akv (J) ≥ 30 longitudinal;
Transverse: Akv ≥ 27J

Thickness >100-150mm
ReH(MPa) ≥490
Rm(MPa) 590-770
A(%) ≥16
Akv (J) ≥ 30 longitudinal;
Transverse: Akv ≥ 27J

Steelmaking process of S550QL1 steel plate
1. Materials (scrap, pig iron and molten iron)
2. Electric furnace (100t electric arc furnace training), converter
3. Refined treatment of molten steel in LF furnace
4. Vacuum treatment of molten steel in VD or VOD furnace
5. Mold casting (multiple key mold casting lines) or continuous casting (large slab caster); (50 ton slab electroslag furnace for remelting one ingot)
6. Heating (continuous furnace and soaking furnace)
7. Steel plate rolling (4100 and 4200mm mill)
8. Heat treatment of steel plate (normalizing, tempering and tempering)
9. Steel plate cutting inspection
10. Warehousing