Q390B is a high-strength low-alloy structural steel widely used in construction, bridges, ships, vehicles, pressure vessels, and other fields. "Q" stands for yield strength, "390" refers to the yield strength of 390 MPa, and "B" represents its quality grade. The chemical composition of Q390B typically includes alloying elements such as carbon, manganese, silicon, vanadium, niobium, etc. The addition of these elements enhances the strength and toughness of the steel.

The yield parameters of Q390B mainly include yield strength, tensile strength, and elongation. Yield strength is the stress value at which the steel begins to undergo permanent deformation under external force; for Q390B, this value is 390 MPa. Tensile strength refers to the maximum stress the steel can withstand during the stretching process, which is generally higher than the yield strength. Elongation is the maximum percentage by which the steel can stretch before fracture, reflecting the material's plasticity.

The yield parameters of Q390B enable it to maintain structural integrity under heavy loads, which is particularly important in engineering applications that require bearing heavy or dynamic loads. However, compared to low-strength steels, Q390B may be more difficult to process, so this must be considered during design and manufacturing.