Characteristics of EN10028-3 P355NL2 Steel
Excellent Low-Temperature Toughness
Impact Temperature Range: P355NL2 belongs to the special low-temperature quality grade steel. The "L2" in its designation indicates a minimum impact temperature of -50°C to -60°C. Some standards require an impact energy of ≥40 J (longitudinal) at -60°C, and it can even maintain resistance to brittle fracture at -70°C.
Brittle Fracture Resistance Mechanism: Grain refinement is achieved by adding microalloying elements such as Nb, Ti, and V, which suppress high-temperature brittleness. Meanwhile, strict control over harmful impurities like sulfur (S ≤ 0.005%) and phosphorus (P ≤ 0.025%) reduces the tendency for low-temperature brittleness.
Application Scenarios: Suitable for extreme low-temperature environments such as polar oil and gas facilities, deep-sea drilling platforms, and LNG storage tanks (-162°C ultra-low temperature), ensuring the safety of equipment during low-temperature storage and transportation.
Good Weldability
Carbon Equivalent Control: With a carbon content ≤ 0.20% and sulfur content ≤ 0.010%, the carbon equivalent (CEV) is low, resulting in low susceptibility to welding cracks. Preheating may not be required before welding (for plate thickness ≤ 15 mm), and only low-temperature preheating at 100-150°C is needed for thick plates (>15 mm).
Welding Process Compatibility: Supports various welding processes, including manual metal arc welding, submerged arc welding, and gas metal arc welding. The welded joints exhibit high performance matching with the base metal after welding.
Strong Adaptability in Processing Performance
Cold Forming Capability: The normalized microstructure is uniform, enabling it to withstand a 180° cold bending test. It is suitable for cold forming processes such as flanging and curling. Annealing is recommended after cold forming to eliminate residual stresses.
Cutting Performance: Supports various cutting methods, including flame cutting, plasma cutting, and laser cutting. The quality of the cut surfaces meets inspection requirements.
Surface Treatment Compatibility: Can undergo anti-corrosion treatments such as sandblasting, painting, and galvanizing to extend service life, making it suitable for corrosive environments like offshore platforms and chemical equipment.
Stable Mechanical Properties
Balance of Strength and Plasticity: The yield strength is ≥355 MPa (for plate thickness ≤ 16 mm), with a tensile strength of 490-630 MPa and an elongation after fracture ≥22% (gauge length 5.65√S₀), ensuring sufficient plastic deformation capacity under load.
Through-Thickness Properties: Available in Z15, Z25, and Z35 grades to control the interlaminar bonding strength in the thickness direction of the steel plate, reducing the risk of lamellar tearing in thick plates (>50 mm).
Fatigue Performance: Exhibits a fatigue limit of ≥250 MPa under alternating loads, making it suitable for applications requiring long-term exposure to dynamic loads, such as wind power equipment and bridges.
