S460QL is a quenched and tempered high-strength structural steel that meets the European standard EN 10025 - 6. It is especially outstanding in low-temperature toughness and is a key material for key projects in low-temperature and heavy-load environments.
Brand Meaning and Corresponding Standards
Each part of its brand has a clear meaning. "S" stands for structural steel, "460" means the minimum yield strength can reach 460MPa when the steel plate thickness is less than 50mm, "Q" represents the quenched and tempered delivery state, and "L" emphasizes that it must meet the impact energy requirements at a low temperature of -40°C. It corresponds to China's Q460E high-strength structural steel. The main difference between the two lies in the details of the implementation standards and some inspection indicators.
Chemical Composition
Its chemical composition is scientifically proportioned and strictly restricted to ensure the balance of strength and low-temperature performance. The maximum carbon content is controlled at 0.2% to avoid excessive carbon content affecting weldability and toughness. Harmful impurities are strictly limited, with phosphorus content ≤0.02% and sulfur content ≤0.01%. It also contains manganese, chromium, and molybdenum to enhance strength. Trace elements such as niobium (≤0.06%) and titanium (≤0.05%) are added optionally. These elements can refine the grain structure and further improve the steel's resistance to low-temperature brittleness.
Mechanical Properties
Its mechanical properties change regularly with the thickness of the steel plate. When the thickness is 3 - 50mm, the minimum yield strength is 460MPa; when it is 50 - 100mm, the yield strength is 440MPa; and when it exceeds 100mm, it is 400MPa. In terms of tensile strength, it is 550 - 720MPa when the thickness is within 100mm, and 500 - 670MPa when the thickness exceeds 100mm. At the same time, its longitudinal V-notch impact energy at -40°C is not less than 30J, which can effectively prevent brittle fracture in extremely cold environments, and the minimum elongation can meet the forming needs of most structural parts.
Delivery Specifications and Heat Treatment
It is generally delivered in the quenched and tempered state. The thickness of the steel plate can be customized according to needs, and the common thickness range is 3 - 850mm. It also supports additional value-added detection and customization services. For example, Z-direction performance detection (Z15/Z25/Z35 grades) can be carried out according to the needs of large structural parts to prevent lamellar tearing. It can also undergo non-destructive testing such as ultrasonic testing and X-ray testing. Its heat treatment process is mainly quenching plus tempering. Sometimes, manufacturers can also adopt accelerated cooling methods such as blast cooling after austenitizing temperature with the buyer's consent, and then perform tempering treatment.
Application Scenarios
It is widely used in fields that require both bearing heavy loads and adapting to low temperatures. In the field of mining machinery, it is used to make core components such as drilling rigs, electric shovels, and mining dump trucks. In the field of construction machinery, it is an important material for cranes, hydraulic supports, and bulldozers. In the field of infrastructure, it can be used to manufacture structural parts such as industrial platforms and bridge supports in alpine regions, which can withstand long-term pressure and resist the impact of low-temperature environments.
What do the letters and numbers in the S460QL grade mean, and which standard does it comply with?
S460QL is a quenched and tempered high-strength structural steel adhering to the European standard EN 10025-6 . Each part of its grade has a clear definition: "S" stands for structural steel, indicating its core use in load-bearing structures; "460" represents a minimum yield strength of 460MPa for plates thinner than 50mm; "Q" signifies the quenched and tempered (调质) delivery state, which balances strength and toughness; "L" denotes enhanced low-temperature performance, requiring compliance with impact energy standards at -40°C . This coding system allows engineers to quickly identify its key performance attributes.
What are the key chemical composition characteristics of S460QL, and how do they affect its performance?
S460QL's chemical composition is strictly regulated to achieve high strength and low-temperature toughness. The maximum carbon content is limited to 0.22% to ensure weldability and avoid brittle cracking . Harmful impurities are strictly controlled: phosphorus ≤0.025% and sulfur ≤0.012%, which reduces the formation of brittle inclusions and improves toughness . It also contains alloy elements such as manganese (≤1.8%), chromium (≤1.6%), and molybdenum (≤0.74%) to enhance hardenability and strength. Trace elements like niobium and titanium are optionally added to refine the grain structure, further boosting resistance to low-temperature brittleness without compromising overall performance .