Steel plate with very low yield point and manufacturing method thereof

Abstract

The invention relates to a steel plate with very low yield point and a manufacturing method thereof. The component design technology means of adopting a component system processed by very low C, super low Si, low Mn, high Als, low N, Ti microalloying and trace B, enhancing the content of acidly soluble Als and the Ti microalloying properly, controlling Ti / N to be not less than 10.0, Als / N to be not less than 12.0 and Ti / C to be not less than 13.0 and the like are adopted to optimize a rolling control process; the microscopic structure of a finished product of the steel plate is single-phase ferrite, the size of the crystal grains of the ferrite is uniform, and the average size of the crystal grains is between 50mum and 100mum; C and N interstitial atoms which are solidly soluble in steel are eliminated, and AlN and Ti (C and N) grains are bulky and are evenly distributed; and the invention obtains very low yield strength (YP=140 to 180MPa), superior room-temperature plastic deformation capability (the uniform elongation rate reaches more than 50 percent), superior impact toughness, superior low-cycle fatigue resistance performance and low rate of work hardening and is especially suitable for manufacturing a shock-resistant damper with a large-sized steel structure.

Description

technical field [0001] The invention relates to a structural steel plate and a manufacturing method thereof, in particular to an extremely low yield point steel plate and a manufacturing method thereof, the yield strength of which is 140-180 MPa, and the elongation δ 5 ≥50%, with excellent low cycle fatigue resistance and weldability. Background technique [0002] As we all know, carbon structural steel is one of the most important engineering structural materials, widely used in shipbuilding, bridge structure, pressure vessel, building structure, automobile industry, railway transportation and machinery manufacturing. The performance of carbon structural steel depends on its chemical composition and the process system of the manufacturing process. Among them, strength, toughness, elongation and weldability are the most important properties of carbon structural steel, which are ultimately determined by the microstructure of the finished steel and the chemical properties of t...

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to provide a steel plate with an extremely low yield point and its manufacturing method. By combining the combination design of the main alloying elements and microalloying elements of the steel plate with the controlled rolling process, the steel plate with an extremely low yield point, excellent impact toughness, In addition to excellent room temperature deformation ability, the steel plate also has excellent welding processability and can withstand large heat input welding. The problem of low fatigue performance

Images