Steel plate for high-strength high-toughness low-yield easily-welding structure and method for manufacturing same

Abstract

The invention provides a steel plate for a high-strength high-toughness low-yield easily-welding structure. The steel plate comprises the following chemical components in percentage by weight: 0.02 to 0.08 percent of C, 0.30 to 0.50 percent of Si, 1.50 to 1.80 percent of Mn, 0.02 to 0.04 percent of Nb, 0.005 to 0.030 percent of Ti, 0.008 to 0.20 percent of Mo, 0.30 to 0.90 percent of Cr, 0.30 to 0.50 percent of Cu, 0.10 to 0.40 percent of Ni, 0.010 to 0.070 percent of Als, and the balance of Fe. The method for manufacturing the steel plate comprises the steps of molten iron pretreatment, rotary furnace smelting, refining, continuous casting and rolling, wherein the steel blank heating temperature before rolling is between 1,050 and 1,220 DEG C, the rolling temperature in a recrystallization area is more than or equal to 1,000DEG C, and the rolling temperature in a non-recrystallization area is between 950 and (Ar3 plus 0 to 100) DEG C; and after rolling, the temperature is held, and the plate blank is subjected to accelerated cooling. The method has the advantages of unnecessary addition of B and V, low cost, short production period, and the obtaining of the bainite plus ferrite structure without complex thermal treatment, and can control the yield of the steel plate below 0.8 under the condition of ensuring high strength, high toughness and good welding property.

Description

technical field [0001] The invention belongs to the technical field of metal materials, and in particular relates to a low-alloy low-yield ratio steel plate and a manufacturing method thereof. Background technique [0002] The light weight of energy-saving steel structural parts is inseparable from its high strength and high toughness, and ensuring the safety of steel structures such as buildings and bridges in the event of earthquakes, fires and accidents requires structural steel to have work hardening ability, yield ratio It is an important parameter to measure the work hardening ability of steel. However, with the increase of the steel grade, the yield strength and tensile strength of the structural steel increase to varying degrees, and the yield strength increases faster, that is, the yield ratio increases, which means that the magnitude of deformation strengthening of the steel plate is relatively Reduced, thereby endangering the safety of structural steel. [0003]...

AI Technical Summary

Problems solved by technology

Although this patent has a lower welding crack sensitivity coefficient and yield strength ratio, it uses a large amount of precious element Ni, which increases the cost, and the Si content is higher, the cleanliness of the steel decreases, the toughness decreases, and the weldability is poor.

The above two patents are only applicable to the production of steel plates with a tensile strength above 700 MPa, and a small amount of B element is added. Because B is difficult to control in the smelting process, it is easy to segregate, causing hot brittleness, and increasing hot pressure processing. difficulty

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