Structure steel plate for bridge with yield strength being 690MPa and production method thereof

Abstract

The invention discloses a structure steel plate for a bridge with the yield strength being 690MPa and a production method thereof. The structure steel plate comprises the following components in percent by weight: 0.040 percent to 0.080 percent of C, 0.20 percent to 0.25 percent of Si, 1.50 percent to 1.65 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.005 percent of S, 0.040 percent to 0.050 percent of Nb, 0.006 percent to 0.018 percent of Ti, 0.25 percent to 0.35 percent of Cr, 0.25 percent to 0.30 percent of Mo, 0.30 percent to 0.40 percent of Cu, 0.20 percent to 0.30 percent of Ni and the balance of Fe and unavoidable impurities, the sensitive composition of welding cracks meets the formula Pcm is less than or equal to 0.22, the carbon equivalent CEV is less than or equal to 0.50, 10C plus 4Cr plus Cu equals to 6.5 to 7.5. The structure steel plate designed and produced by the process has good toughness; the yield strength Rel is more than or equal to 690MPa, the tensile strength Rm is more than or equal to 770MPa, the elongation A is more than or equal to 18 percent, and -40 DEG C low-temperature impacting performance is more than or equal to 100J. Compared with the existing bridge steel technology, the structure steel plate disclosed by the invention has the advantages that the strength level is greatly improved; in addition, the welding performance of the steel plate is improved by strictly controlling the carbon equivalent CEV to be less than or equal to 0.50 and Pcm to be less than or equal to 0.22.

Description

technical field [0001] The invention belongs to the technical field of structural steel for bridges in the metallurgical industry, and in particular relates to a structural steel plate for bridges with a yield strength of 690MPa and a production method thereof. Background technique [0002] With the rapid development of my country's transportation construction, the span, operating load, and driving speed of bridges are gradually increasing, thus putting forward higher technical requirements for bridge steel. High-performance bridge steels with high strength, high toughness, excellent welding performance, fatigue resistance and good weather resistance that meet the development needs of bridge engineering will be the main direction of its development. The use of high-strength steel can better meet the needs of long-span steel bridges or some heavy-stress structures, reduce the thickness of the steel plate and reduce the amount of ordinary-strength steel, and can reduce the sel...

AI Technical Summary

Problems solved by technology

The disadvantage of this invention is that the strength is too low and the carbon content is too high. The increase of carbon content will increase the carbon equivalent of the steel plate, and it is difficult to ensure the good welding performance of the steel plate

[0005] The analysis of published patents and literature found that there are currently two main problems with structural steel for bridges: one is that the strength level is low, and most of the research on bridge steels below 500MPa is concentrated; the other is that the invented steel has a high carbon content, which is Seriously affects the weldability of bridge steel and increases the cost of bridge construction

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