What is the difference between S690QL and S690Q?
S690Q is a high-strength quenched and tempered structural steel with a minimum yield strength of 690 MPa, designed for heavy-duty applications where weight reduction and high load capacity are critical.
S690QL is a sub-grade of S690Q specifically optimized for low-temperature service, guaranteeing higher impact toughness at temperatures as low as -40°C to ensure safety and reliability in freezing environments.
The primary difference between S690QL and S690Q lies in their specified impact toughness at low temperatures, as defined by the European standard EN 10025-6.
Here's a simple breakdown:
| Feature | S690Q (Base Grade) | S690QL (Sub-Grade) |
|---|---|---|
| Key Difference | Standard quenched & tempered grade. | "L" stands for "Low Temperature" service. |
| Impact Toughness | Must meet minimum impact energy at 0°C (32°F). | Must meet higher minimum impact energy at -40°C (-40°F). |
| Typical Application | General high-strength applications where extreme low-temperature service is not a critical design factor. | Arctic conditions, offshore structures, high-latitude construction, or any application where the steel must remain tough in very cold environments. |
| Chemical Composition & Manufacturing | Essentially identical. Both are quenched & tempered to achieve 690 MPa yield strength. The "L" grade undergoes stricter quality control to guarantee low-temperature toughness. | |
| Cost | Generally lower cost. | Slightly more expensive due to tighter production controls and testing. |
In Summary:
Think of S690QL as a tougher, more reliable version of S690Q for freezing conditions. If your structure or machine (e.g., a crane in Scandinavia, mining equipment in Canada, or an offshore platform) will operate in temperatures at or below -20°C, engineers will specify S690QL to ensure safety and prevent brittle fracture. For most other high-strength applications, S690Q is sufficient.
What is S690Q steel?
S690Q is a high-strength quenched and tempered structural steel grade with a minimum yield strength of 690 MPa, often used in demanding construction and lifting applications.
What are the properties of S690Q steel?
S690Q offers high strength, good toughness at low temperatures, and excellent weldability due to its quenched and tempered microstructure.
What is the difference between S690QL and S690Q?
S690QL is a sub-grade with specified low-temperature impact toughness, while S690Q is the base grade; both share the same minimum yield strength.
Where is S690Q steel used?
It is commonly used in heavy machinery, mobile cranes, mining equipment, and advanced structural components where high strength-to-weight ratio is critical.
How to weld S690Q steel?
Welding S690Q typically requires low-hydrogen electrodes, preheating, and controlled heat input to maintain its mechanical properties and prevent cracking.
What is the chemical composition of S690Q?
S690Q contains elements like carbon, manganese, silicon, and micro-alloys such as niobium, vanadium, and titanium, with precise limits to ensure its properties.
Is S690Q steel corrosion resistant?
No, S690Q is not inherently corrosion-resistant; it requires protective coatings or paints for use in corrosive environments.
What are the machining guidelines for S690Q?
Machining S690Q requires robust tools, adequate cooling, and slower speeds due to its high strength and hardness.
What is the price of S690Q steel plate?
The price of S690Q varies based on thickness, quantity, and market factors, but it is generally more expensive than standard structural steels due to its advanced processing.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
