P460QL1 is a quenched and tempered alloy structural steel, mainly applied in the fabrication of low-temperature pressure vessels and boilers. It features excellent low-temperature toughness, high strength, and superior weldability, which ensures stable and reliable performance even under harsh operating conditions.
EN10028-6 P460QL1 Chemical composition
| Element | P460QL1 Max % | Element | P460QL1 max % |
| C | 0.18 | Cr | 0.50 |
| Si | 0.50 | Mo | 0.50 |
| Mn | 1.70 | Cu | 0.30 |
| P | 0.020 | Nb | 0.05 |
| S | 0.010 | Ni | 1.00 |
| N | 0.015 | TI | 0.03 |
| B | 0.005 | V | 0.08 |
EN 10028-6 P460QL1 Mechanical properties
| Grade | Heat Treatment | Thickness | Yield Strength | Tensile Strength | Elongation | Impact Energy |
| P460QL1 | +QT | (mm) | MPa (min) | MPa | % (min) | (KV J) (min) |
| -40 degree | ||||||
| ≤ 50 | 460 | 550-720 | 19 | 27 | ||
| 50to ≤100 | 440 | 550-720 | 19 | 27 | ||
| 100o ≤150 | 400 | 500-670 | 19 | 27 |
Processing of P460QL1
Cutting and blanking: P460QL1 can be cut using flame cutting, plasma cutting, or laser cutting. For thick plates, flame cutting is commonly used, but proper preheating and post-cutting cooling control are needed to prevent thermal cracking. Plasma and laser cutting offer higher precision and faster speeds for medium and thin plates.
Forming and bending: The steel has good cold and hot formability. Cold bending is suitable for plates with moderate thickness, but the minimum bend radius should be respected to avoid cracking. Hot forming is recommended for complex shapes or thick plates, typically performed at temperatures between 800°C and 1100°C, followed by controlled cooling to maintain mechanical properties.
Welding procedures: P460QL1 is weldable by standard methods such as SMAW, GMAW, FCAW, and SAW. Preheating is often required for plates thicker than 25 mm or in low-temperature environments to reduce hydrogen-induced cracking. Interpass temperature should be controlled below 250°C, and post-weld heat treatment (PWHT) may be applied to improve toughness and reduce residual stresses.
Machining: The steel has satisfactory machinability, allowing turning, milling, drilling, and grinding operations. However, due to its high strength, appropriate cutting tools and parameters are necessary to ensure efficiency and tool life. Coolants are recommended to reduce heat and improve surface finish.
Heat treatment: P460QL1 is supplied in the quenched and tempered (Q&T) condition. Additional heat treatment is generally not required, but stress relief annealing may be performed after heavy fabrication or welding to enhance dimensional stability and reduce residual stresses.
Surface treatment and protection: To improve corrosion resistance, surfaces can be cleaned by shot blasting or pickling, followed by coatings such as epoxy, polyurethane, or anti-corrosive paint. In marine or highly corrosive environments, additional protection like cathodic protection may be applied.
Advantages of P460QL1
High strength and toughness combination: With a minimum yield strength of 460 MPa and excellent low-temperature impact toughness down to -40°C, P460QL1 provides a superior balance of strength and ductility, making it ideal for heavy-duty and low-temperature applications.
Excellent weldability: The steel is designed to be easily welded using common processes such as SMAW, GMAW, FCAW, and SAW. Its controlled chemical composition minimizes the risk of cold cracking and ensures good mechanical properties in the heat-affected zone.
Good formability and machinability: P460QL1 exhibits good cold and hot formability, allowing it to be bent, rolled, and shaped into complex components. It also has satisfactory machinability, enabling efficient processing during fabrication.
High resistance to brittle fracture: Thanks to its fine-grained microstructure and quenched-and-tempered heat treatment, P460QL1 offers excellent resistance to brittle fracture, which is crucial for pressure vessels and structures operating at low temperatures.
Reliable performance under high pressure: The steel's high strength and toughness make it suitable for high-pressure applications, ensuring structural integrity and long-term reliability in pressure vessels, boilers, and other critical equipment.
Wide range of applications: Due to its versatile properties, P460QL1 is used in various industries, including petrochemical, chemical, power generation, and offshore engineering, making it a cost-effective and reliable choice for many heavy engineering projects.
P460QL1 applications
Pressure vessels and storage tanks: P460QL1 is widely used in the fabrication of pressure vessels, including spherical tanks, cylindrical tanks, and large storage tanks for oil, gas, and chemical products. Its high yield strength and good low-temperature toughness make it suitable for operating conditions with high internal pressure and low ambient temperatures.
Petrochemical and chemical equipment: It is used to manufacture reactors, heat exchangers, separators, and other key equipment in refineries, chemical plants, and gas processing facilities. The steel's excellent weldability and resistance to brittle fracture ensure the reliability and safety of these critical components.
Power industry applications: P460QL1 is applied in the construction of boilers, pressure parts of steam generators, and high-pressure pipelines in thermal power plants and nuclear power plants. It can withstand high temperatures and pressures while maintaining good mechanical properties.
Offshore and marine structures: Due to its good toughness at low temperatures and high strength, P460QL1 is used in offshore platforms, FPSO units, and other marine structures exposed to harsh environments such as low temperatures, high winds, and corrosive seawater.
General heavy engineering: It is also used in heavy machinery, large-diameter pipes, and structural components that require high strength, good weldability, and excellent impact resistance, such as in the construction of bridges, cranes, and mining equipment.
application conditions
Temperature range: P460QL1 is designed for service in low to moderate temperature environments. It maintains good toughness at temperatures as low as -40°C, making it suitable for cold climates and low-temperature process equipment. However, its long-term use at temperatures above 350°C is generally not recommended to avoid loss of strength and toughness.
Pressure requirements: This steel is suitable for high-pressure applications, typically used in pressure vessels and components operating at pressures from medium to high levels. Its minimum yield strength of 460 MPa ensures sufficient resistance to internal and external pressures, providing structural integrity under demanding loading conditions.
Welding and fabrication conditions: P460QL1 requires appropriate welding procedures to maintain its mechanical properties. Preheating may be necessary for thick plates to prevent cold cracking, especially in low-temperature environments. Interpass temperature control and post-weld heat treatment (PWHT) are often applied to reduce residual stresses and improve toughness in the heat-affected zone.
Environmental conditions: It is suitable for use in various industrial environments, including petrochemical plants, refineries, power stations, and offshore installations. However, in highly corrosive environments such as those with chloride or acidic media, additional corrosion protection measures (e.g., coatings, linings, or cathodic protection) are required to ensure long-term durability.
Loading and structural conditions: P460QL1 is used in structures subjected to static, cyclic, and dynamic loads. It is suitable for heavy engineering applications where high strength, good fatigue resistance, and resistance to brittle fracture are essential, such as in large storage tanks, reactors, and pressure-containing components.
If you have project requirements for P460QL1, we welcome your inquiry. GNEE maintains a large inventory of commonly used high strength steel grades for your selection.For detailed mechanical properties, chemical composition, and technical data, as well as free samples, please contact our factory immediately. We offer competitive prices, stable quality, and professional service. Email:beam@gneesteelgroup.com.
What is the minimum yield strength of P460QL1?
The minimum yield strength of P460QL1 is 460 MPa. This high yield strength enables it to bear large loads and pressures, making it suitable for manufacturing high-pressure equipment and structural parts in industrial fields.
Which standards does P460QL1 comply with?
P460QL1 complies with the European standard EN 10028-3. This standard specifies the technical requirements, test methods, inspection rules and other contents of quenched and tempered pressure vessel steels, ensuring product quality and safety.
What is the difference between P460QL1 and P460Q?
The main difference is the low-temperature toughness level. P460QL1 has higher low-temperature toughness (test temperature -20℃) than P460Q, and is more suitable for low-temperature working environments. Their yield strength and tensile strength are basically the same.
Does P460QL1 need heat treatment after processing?
It depends on the processing method and application scenario. For important components, post-processing heat treatment (such as tempering) is usually required to eliminate internal stress, improve toughness and ensure the dimensional stability of the workpiece.
What is the maximum thickness of P460QL1 plates?
The maximum thickness of P460QL1 plates can reach 200 mm, depending on the manufacturer's production capacity and technical level. Thicker plates are usually used for large pressure vessels and heavy-duty structural parts.
What is the impact toughness requirement of P460QL1?
At -20℃, the impact energy of P460QL1 shall not be less than 34 J (Charpy V-notch test). This ensures that the material has sufficient toughness to resist impact loads in low-temperature environments.
Can P460QL1 be cold-formed?
Yes, P460QL1 can be cold-formed, but the forming temperature and deformation rate need to be controlled. Excessive cold deformation may lead to work hardening and reduce toughness, so appropriate annealing treatment may be required after forming.
What are the surface quality requirements of P460QL1?
The surface of P460QL1 shall be clean, free of cracks, folds, delaminations, inclusions and other defects. Minor surface defects that do not affect the use can be repaired by grinding, and the depth of repair shall not exceed the allowable deviation of the plate thickness.
What is the tensile strength range of P460QL1?
The tensile strength range of P460QL1 is 570-720 MPa. This strength index is an important basis for judging whether it can meet the use requirements of various mechanical structures and pressure vessels.
What is the application temperature range of P460QL1?
P460QL1 is suitable for working environments with temperatures ranging from -20℃ to 350℃. Its excellent low-temperature toughness ensures that it will not brittle fracture at low temperatures, and it can maintain stability at medium and high temperatures.