S500QL and S690QL are both high-strength structural steels (EN 10025-6) quenched and tempered for heavy applications, but the key difference is strength: S690QL has a minimum yield strength of 690 MPa (for typical thicknesses), while S500QL has a minimum yield strength of 500 MPa, making S690QL significantly stronger and allowing for leaner designs, though both offer good weldability and impact toughness for their strength levels.
Chemical composition for S500QL steel plate
| Main chemical elements composition of S500QL steel plate | |||||||
| C | Si | Mn | P | S | N | B | Cr |
| 0.20 | 0.80 | 1.70 | 0.020 | 0.010 | 0.015 | 0.005 | 1.50 |
| Cu | Mo | Nb | Ni | Ti | V | Zr | |
| 0.50 | 0.70 | 0.06 | 2.0 | 0.05 | 0.12 | 0.15 | |
Chemical composition of S690QL steel plate
| C | Si | Mn | P | S | Ni | Cr | Mo | Cu | Nb | V | Ti | N | Zr | B |
| ≤0.2 | ≤0.8 | ≤1.7 | ≤0.02 | ≤0.010 | ≤2 | ≤1.5 | ≤0.7 | ≤0.5 | ≤0.06 | ≤0.12 | ≤0.05 | ≤0.015 | ≤0.15 | ≤0.005 |
Mechnical property for S500QL steel plate:
| Thickness (mm) | |||
| S500QL | ≥ 3 ≤ 50 | > 50 ≤ 100 | > 100 |
| Yield strength (≥Mpa) | 500 | 480 | 440 |
| Tensile strength (Mpa) | 590-770 | 590-770 | 540-720 |
Mechanical properties of S690QL steel plate:
| Delivery Status | Thickness | Mechanical properties | |
| Quenched and tempered | 3-50mm | ReH(MPa) | ≥690 |
| Rm(MPa) | 770-940 | ||
| A(%) | ≥14 | ||
| Impact temperature | -40 | ||
| Longitudinal Akv(J) | ≥30 | ||
| >50-100mm | ReH(MPa) | ≥650 | |
| Rm(MPa) | 760-930 | ||
| A(%) | ≥14 | ||
| Impact temperature | -40 | ||
| Longitudinal Akv(J) | ≥30 | ||
| >100-150mm | ReH(MPa) | ≥630 | |
| Rm(MPa) | 710-900 | ||
| A(%) | ≥14 | ||
| Impact temperature | -40 | ||
| Longitudinal Akv(J) | ≥30 | ||
Applications: Both are used in heavy machinery, construction, transport, and lifting equipment, but S690QL's higher strength suits more demanding, load-bearing roles.
Standard (EN 10025-6): Both are part of the same high-yield strength, quenched & tempered (Q) steel family, with the 'L' indicating good low-temperature impact properties.
Design & Efficiency: The superior strength of S690QL allows for leaner designs (less material) while maintaining payload capacity, leading to energy efficiency.
In essence: S500QL is strong, but S690QL is in a higher class, offering superior load-bearing capabilities for critical components.
