Introduction to S690QL1 steel plate
S690QL1 steel plate is a quenched and tempered high-strength steel plate. "S" means it is European standard, and the corresponding national standard is Q690F high-strength structural steel. It is used for the manufacture of key components with low temperature resistance and high strength, construction machinery, mining machinery structure, etc.
S690QL1 is a premium quenched and tempered (Q&T) high-strength structural steel plate compliant with European EN 10025-6:2004 standard, corresponding to China's Q690F in national standards. Its designation carries clear technical meanings: "S" for European standard, "690" for ≥690MPa minimum yield strength, "Q" for quenched and tempered treatment, and "L1" for enhanced low-temperature toughness exceeding the base S690Q grade.
S690QL1 steel plate characteristics:
S690QL1 adopts controlled rolling technology. From the chemical composition of the steel plate, it can be seen that the content of harmful elements S and P is relatively low, indicating that its steel quality is pure and its welding performance is good.
Delivered in quenched and tempered condition, it undergoes heating to 900–950°C for quenching and 550–650°C for tempering, forming a tough tempered martensite structure that balances high strength and ductility. With precise chemical control, it features ≤0.20% carbon, ultra-low sulfur (≤0.010%) and phosphorus (≤0.020%), plus optimized nickel, chromium-molybdenum additions, ensuring high purity and excellent weldability (CET ≤0.45%).
Mechanically, it offers 770–940MPa tensile strength, ≥14% elongation, and ≥40J impact toughness at -40°C (typical ≥55J), with mandatory Z-direction performance to resist lamellar tearing. Easy to machine with proper tools and cooling, it requires controlled preheating (100–200°C) and low-hydrogen consumables for welding.
Widely used in harsh environments, it serves construction machinery (cranes, excavators), mining equipment (mining trucks, hydraulic supports), industrial structures in cold regions, and specialized polar exploration vehicles, excelling at temperatures as low as -60°C.
1. What standard does S690QL1 comply with and what is its Chinese equivalent grade
It adheres to EN 10025-6:2004 and corresponds to Q690F high-strength structural steel in China's national standard system.
2. What is the core indicator of its low-temperature toughness
Impact energy ≥40J at -40°C (average of 3 specimens), typical value 55J; optional -60°C test with ≥35J.
3. What should be noted for welding S690QL1
Preheat to 100-200°C (by thickness), use low-hydrogen consumables; post-weld heat treatment at 550-600°C for thick plates.
4. Why is it suitable for cold-region mines
Withstands -30°C to -50°C, has 770-940MPa tensile strength, and resists 300-400t loads and rock abrasion.
5. What quality control measures are used in production
Includes ultrasonic testing (EN 10160), mechanical property testing, microanalysis to ensure no internal defects and compliance.
6. What advantages does it have over S690Q
"L1" means better low-temperature toughness, lower sulfur (≤0.010%), superior brittle fracture resistance and weldability.