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Bridge structural steel plate and producing method thereof

A technology of bridge structure and production method, applied in the field of high-performance Q420qE steel and its production, can solve the problems of low strength level, shortened service life of components, bearing weight limitation, etc.

Inactive Publication Date: 2008-12-31
HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the steel plate produced by the TMCP process has a large internal stress, and the component is easily deformed during processing and use, which affects the performance of the product and reduces the service life of the component.
[0004] The high-performance bridge steels produced in China in the past are mainly Q370qE and Q420qD, which are basically produced by TMCP or TMCP plus normalizing process. The strength level is low, the bearing weight is limited to a large extent, and the low temperature resistance is not good enough
At the same time, the Q420qD produced according to GB / T 714-2000 has a plate thickness effect - as the thickness of the steel plate increases, the yield strength and tensile strength of the steel plate decrease to a certain extent; Due to the large internal stress, the components are easily deformed during processing and use, especially thick steel plates, which seriously affect the service life of the bridge

Method used

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  • Bridge structural steel plate and producing method thereof
  • Bridge structural steel plate and producing method thereof
  • Bridge structural steel plate and producing method thereof

Examples

Experimental program
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Effect test

Embodiment example 1

[0032] Billets with the chemical composition in Table 2 were used for rolling.

[0033] The chemical composition of table 2 embodiment 1

[0034]

[0035] The heating temperature of the heating furnace is between 1175 and 1207°C; the starting temperature of rough rolling is ≥1020°C, the reduction rate of a single pass is required to be ≥12%, and the thickness of the intermediate billet is 170mm; Reduction rate ≥ 45%; start rolling temperature ≤ 880°C, final rolling temperature ≤ 850°C in the second stage of finishing rolling, cumulative reduction in the last three passes ≥ 34.5%; ACC cooling rate 10°C / S, final cooling temperature 500~ 560°C; tempering temperature 580-600°C, furnace time (min) = plate thickness × 1min / mm+50min.

[0036] The high-performance bridge structural steel plate Q420qE produced by the above process has relatively fine bainite and a small amount of ferrite structure, the grain size is above 10 grades, and the grain size difference is within 2.0 grade...

Embodiment example 2

[0038] Billets with the chemical composition in Table 3 were used for rolling.

Embodiment 2

[0039] Table 3 Example 2 Chemical Components

[0040]

[0041] The heating temperature of the heating furnace is between 1180 and 1240°C; the starting temperature of rough rolling is ≥1000°C, the final rolling temperature is >950°C, the reduction in a single pass is required to be ≥15%, and the thickness of the intermediate billet is 140mm; the starting temperature of finishing rolling is 880°C ~920℃, cumulative rolling reduction ≥ 50%; starting temperature of finish rolling II stage ≤ 880℃, cumulative rolling reduction of the last three passes ≥ 45%, final rolling temperature 814~833℃, ACC cooling rate 10~15 ℃ / S, final cooling temperature 280~420℃; tempering temperature 550℃, time in furnace (min)=plate thickness×1min / mm+50min.

[0042] The high-performance bridge structural steel plate Q420qE produced by the above process has a fine and uniform bainite structure, the grain size is controlled at 11-12 grades, the grain size difference of the structure is controlled within ...

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Abstract

The invention relates to a high performance bridge structure steel plate as well as a production method. The steel comprises the chemical constituents, in weight percent: 0.02 percent to 0.06 percent of carbon, 0.15 to 0.25 percent of silicon, 1.40 percent to 1.60 percent of manganese, phosphorus<=0.02 percent, sulfur<=0.010 percent, 0.025 percent to 0.045 percent of niobium, 0.008 to 0.020 percent of titanium, 0.020 percent to 0.050 percent of aluminum, 0.15 to 0.30 percent of nickel, 0.25 to 0.35 percent of chromium, 0.15 to 0.30 percent of molybdenum, 0.25 to 0.35 percent of copper, nitrogen<=0.005 percent, balance iron. The method has the production processes of: 1. hot metal pretreatment, 2. converter smelting, 3. LF refining, 4. VD vacuum degassing or RH decarburization degassing, 5. continuous casting, 6. slab heating, 7. rough rolling, 8. finish rolling, 9. cooling control by ACC, 10. tempering, 11. finishing, and 12. warehousing to finished products.

Description

technical field [0001] The invention relates to a bridge structural steel plate and a production method thereof, in particular to a high-performance Q420qE steel and a production method thereof. technical background [0002] With the development of transportation and urban construction, there are more and more railway bridges, highway bridges, and urban viaducts across large rivers, rivers, and seas, and the spans are getting larger and larger. High-strength, light-weight, and multi-functional materials for bridge construction are proposed. Performance requirements, the original general-strength bridge structure steel is difficult to meet the needs of modern bridge construction. [0003] The high-performance bridge steel SM570N produced in Japan adopts the quenching and tempering process, which not only has a complicated production process, high production costs, but also poor weldability of the steel plate. Later, Japan used TMCP technology to improve the precipitation har...

Claims

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Application Information

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IPC IPC(8): C22C38/58C22C38/48C22C33/00C21C7/04C21C7/10C21D8/02
Inventor 曹志强罗登夏政海谭小斌龙安辉刘丹
Owner HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
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