Ultrawide and ultrafine gauge structural steel plate for bridges and production method thereof

Abstract

The invention provides an ultrawide and ultrafine gauge structural steel plate for bridges and a production method thereof. The ultrawide and ultrafine gauge structural steel plate for bridges consists of the following chemical components by weight: C: 0.12 to 0.17 percent; Si: 0.20 to 0.45 percent; Mn: 1.25 to 1.50 percent; S: 0.010 percent or less; P: 0.020 percent or less; Nb: 0.010 to 0.040 percent; Ti: 0.008 to 0.030 percent; Als (standing for acid-soluble aluminium): 0.015 to 0.050 percent; N: 40 multiplied by 10 negative 6 or less; O: 20 multiplied by 10 negative 6 or less; H: 2 multiplied by 10 negative 6 or less; and the balance of iron and inevitable impurities. According to the invention, the ultrawide and ultrafine gauge structural steel plate for bridges has excellent low-temperature impact resistance, can meet the construction requirements of high-speed multi-track railways and wide highway bridges, and also can be widely used in engineering structures such as buildings, traffic and ocean platforms.

Description

technical field [0001] The invention relates to a bridge structural steel plate and a production method thereof, more specifically, the invention relates to a structural steel plate for an ultra-wide and thin bridge and a production method thereof. Background technique [0002] Bridge steel plate is a steel plate specially used to manufacture railway or highway steel structure bridges. It is required to have high strength, toughness, and withstand the dynamic load and impact of rolling stock, as well as good fatigue resistance, weldability and certain low temperature aging impact. Toughness, at present, steel plates with a yield strength of 345MPa are the most widely used in bridge steel structures. In the manufacturing process of the bridge steel structure, due to the structural design requirements, some components are welded with ultra-wide and thin steel plates with a thickness of 6-12mm and a width of 3100-4100mm. Because the length of the thin-gauge steel plate is long...

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Problems solved by technology

[0004] After analyzing the published patents and documents, it is found that although various enterprises or institutions have researched on bridge steel plates with a yield strength of 345MPa, the contents mentioned either only involve extra-thick specifications, or are produced by hot rolling mills. Steel coils have not yet been involved in the use of medium and heavy plate rolling mills to roll thin-gauge steel plates with a thickness of less than 12mm, and the industry agrees that there are reasons for rolling ultra-wide thin-gauge steel plates with a thickness of 6-12mm and a width of 3100-4100mm in the production process. During the rolling process, the temperature drop is too fast, the rolling resistance is too large, or the roll shape is unreasonable, resulting in plate shape problems such as scooping, wave shape, and camber after rolling, and shock fluctuations caused by unreasonable rolling temperature and other process parameters , and the normalizing treatment of thin-gauge steel plates, the problem of low strength, and difficult production

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