Rare-earth weather-proofing bridge steel plate with yield strength being 420MPa and production method of rare-earth weather-proofing bridge steel plate

A yield strength and rare earth technology, applied in the field of yield strength 420MPa grade rare earth weathering bridge steel plate and its production field, can solve problems such as increasing cost, and achieve the effects of short production cycle, low production cost and simple preparation process.

Inactive Publication Date: 2018-01-12
BAOTOU IRON & STEEL GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But it needs to go through the tempering process, which increases the cost

Method used

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  • Rare-earth weather-proofing bridge steel plate with yield strength being 420MPa and production method of rare-earth weather-proofing bridge steel plate
  • Rare-earth weather-proofing bridge steel plate with yield strength being 420MPa and production method of rare-earth weather-proofing bridge steel plate
  • Rare-earth weather-proofing bridge steel plate with yield strength being 420MPa and production method of rare-earth weather-proofing bridge steel plate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Smelt according to the chemical composition shown in Table 1, and cast into a steel ingot. The steel ingot is heated to 1210°C for a total furnace time of 252 minutes. The first stage rolling is carried out on the experimental rolling mill, namely rolling in the austenite recrystallization zone. The start-rolling temperature is 1176℃, and the reduction in the first and second passes should be greater than 10%, and at least the reduction in the first and second passes should be controlled at 25% or more. When the thickness of the rolled piece is 45mm, wait on the roller table. The temperature reaches 930°C, and then the second stage rolling is carried out, namely rolling in the austenite non-recrystallized region. The final rolling temperature is 830°C, and the thickness of the finished steel sheet is 14mm. After rolling, the steel plate enters the laminar flow cooling device and is cooled to 630℃ at a rate of 10℃ / s, and finally the steel plate can be obtained.

Embodiment 2

[0044] The implementation is the same as in Example 1, where the heating temperature is 1220℃, the total furnace time is 256 minutes, the opening temperature of the first stage rolling is 1175℃, the thickness of the intermediate billet is 60mm, and the opening temperature of the second stage rolling It is 925℃, the final rolling temperature is 836℃, and the thickness of the finished steel plate is 20mm. After the rolling is finished, the steel sheet enters the laminar flow cooling device and is cooled to 620°C at a rate of 12°C / s, and finally the steel sheet can be obtained. The 500 times metallographic structure of the steel strip is shown as figure 1 Shown.

Embodiment 3

[0046] The embodiment is the same as in Example 1, where the heating temperature is 1226°C, and the total furnace time is 260 minutes; the opening temperature of the first stage rolling is 1180°C, and the thickness of the intermediate billet is 80mm; the opening temperature of the second stage rolling is The final rolling temperature is 930°C, the final rolling temperature is 850°C, and the thickness of the finished steel sheet is 40mm. After rolling, the steel sheet enters the laminar flow cooling device and is cooled to 610°C at a rate of 15°C / s. Finally, the steel sheet can be obtained.

[0047] Table 1 Chemical composition of Examples 1 to 3 of the present invention (wt%)

[0048] Example

C

Si

Mn

P

S

Cu

Ni

Cr

Als

Ce

1

0.08

0.23

0.63

0.014

0.004

0.31

0.21

0.48

0.025

0.0008

2

0.08

0.21

0.61

0.014

0.004

0.33

0.22

0.47

0.024

0.0042

3

0.09

0.25

0.73

0.011

0.002

0.34

0.18

0.43

0.028

0.0024

[0049] The steel strips of Examples 1 to 3 of the present invention were tested for mechanical properties, and the test...

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Abstract

The invention relates to a rare-earth weather-proofing bridge steel plate with the yield strength being 420MPa and a production method of the rare-earth weather-proofing bridge steel plate. The production method comprises the steps of smelting and casting, heating and rolling, and cooling. In the step of the heating and rolling, the heating temperature is 1200-1220 DEG C and the total time insidea furnace is greater than or equal to 240 min; the first stage of the rolling is carried out in an austenite recrystallization zone, the initial rolling temperature is 1130-1180 DEG C in the rolling process, the reduction rate in the first pass to the second pass shall be greater than 10%, and the reduction rate in at least 1-2 of the rest passes is controlled above 25%; and the second stage of the rolling is carried out in an austenite non-recrystallization zone, the initial rolling temperature is less than or equal to 930 DEG C, the thickness of a middle blank is 2.0-3.5 times of the thickness of a finished product, and the finish rolling temperature is 830-850 DEG C. The yield strength of the steel plate is greater than 420MPa, and has the advantages that the steel plate is low in yieldstrength ratio, and good in corrosion resistance, low temperature toughness, cold forming performance and welding performance, and can be used in a coating-free manner; a production process flow is simple; a production cycle is short; and the cost is low.

Description

Technical field [0001] The invention relates to the technical field of steel smelting, in particular to a rare earth weather-resistant bridge steel plate with a yield strength of 420MPa and a production method thereof. Background technique [0002] The bridge steel used in my country has gradually developed from the initial A3 grade to the current Q500q or even higher. The traditional bridge steel not only has poor impact toughness, weldability, fatigue, etc., but also resists atmospheric and marine corrosion. The performance is worse. As the spans of modern bridges are getting larger and larger, the design speed is getting higher and higher, and the safety and reliability of bridge structures are becoming more and more stringent. This is not only a huge challenge for bridge designers, but also higher requirements for the quality of bridge steel. Not only must it have high strength to meet the requirements of structural lightweight, but also have excellent low-temperature toughne...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/04C22C38/02C22C38/06C22C38/48C22C38/50C22C38/42C21D8/02
Inventor 杨雄高军吴章忠王雪莲黄利姜秉坤卢晓禹王海明
Owner BAOTOU IRON & STEEL GRP
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