S355NL low alloy high strength steel plate belongs to EN 10025-23: normalizing / normalizing rolling weldable fine grain structure steel plate. The letter N specifies the normal delivery conditions; L is referred to as the temperature ratio of shock absorption function test is higher than 50, and the impact value is not less than 27J. S355NL low alloy high strength steel plate is mainly used for large-scale welding structures such as large ships, bridges, power station equipment, medium and high pressure boilers, pressure vessels, vehicles, hoisting machinery, mining machinery, etc. The corresponding standard of S355NL low alloy high strength steel plate is GB Q345E, JIS sev24; ASTM grade 50.
S355NL low alloy high strength steel plate contains 0.13% - 0.17% carbon and 1.30% - 1.50% manganese. The physical properties of S355NL low alloy high strength steel plate are greatly improved by adding niobium and vanadium. S355NL low alloy high strength steel plate is under the influence of crack sensitivity, high strength and other factors of subperitectic steel and uneven cooling, low straightening temperature, deep surface vibration mark, and mismatch of physical properties of protective slag. S355NL low alloy high strength steel plate is prone to fine cracks during surface solidification, continuous casting billet cooling and straightening.
