Steel plate for low-carbon high-niobium extra-high strength welding structure and method for manufacturing same

Abstract

The invention provides a steel plate for a low-carbon high-niobium high strength welding structure. The steel plate comprises the following chemical components in percentage by weight: 0.015 to 0.075 percent of C, 0.20 to 0.50 percent of Si, 1.63 to 2.0 percent of Mn, 0.081 to 0.12 percent of Nb, 0.005 to 0.030 percent of Ti, 0.0005 to 0.0030 percent of B, 0.50 to 0.95 percent of Cr, 0.70 to 1.25 percent of Cu, 0.50 to 1.50 percent of Ni, 0.30 to 0.60 percent of Mo, 0.010 to 0.050 percent of Als, and the balance of Fe and inevitable impurities. The method for manufacturing the steel plate comprises the steps of molten iron pretreatment, rotary furnace smelting, refining, continuous casting and rolling, wherein the rolling process adopts the HTP plus RPC process, the heating temperature before rolling is between 1,140 and 1,220 DEG C, and two-stage controlled rolling is adopted. The steel plate is low in carbon content and high in Nb content, so that the initial rolling temperature of the non-recrystallization controlled rolling is increased, the temperature holding time is short, and the manufacturing efficiency is high; because the carbon content and the carbon equivalent are low, the welding performance is good; and with the HTP plus RPC plus annealing process, the steel plate for the welding structure with good toughness and plasticity and the yield strength more than or equal to 960N / mm<2> can be manufactured.

Description

technical field [0001] The invention belongs to the technical field of metal materials, and in particular relates to a low-alloy high-performance steel plate and a manufacturing method thereof. Background technique [0002] At present, the development trend in fields such as construction machinery, heavy-duty trucks, cement pump trucks, semi-trailers, containers, and pressure pipes of hydropower stations is to use more and more high-strength and ultra-high-strength welded structural steels. Carrying capacity, saving energy. At the same time, ultra-high-strength steel plates are required to have the characteristics of low cost, good welding performance, and high low-temperature impact toughness. [0003] Internationally, a number of patents have been formed on the manufacturing method of ultra-high-strength steel plates with a yield strength of about 960MPa, such as: [0004] The publication number CN1148416A that Nippon Steel Co., Ltd. applied for in China is named "high-s...

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Problems solved by technology

[0008] In view of the defects in the above-mentioned prior art, such as low non-recrystallized controlled rolling temperature, large mill load, long waiting time, low production efficiency, poor welding performance, low steel plate strength level, etc., the purpose of the present invention is to overcome the disadvantages of the prior art. Insufficient to provide a yield strength ≥ 960N / mm 2 Grade ultra-high strength welded structural steel and production method thereof

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