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Titanium microalloyed Q355B structural steel plate and recrystallization controlled rolling process method thereof

A Q355B, micro-alloying technology, applied in the field of medium and heavy plate production, can solve problems such as large power consumption and electrode consumption, adverse effects on internal quality, affecting rolling rhythm, etc., to achieve low manufacturing costs and suppress grain growth. Large, fast-paced effects

Inactive Publication Date: 2021-07-13
天津市新天钢钢铁集团有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the alloying process after converter smelting, due to the addition of a large amount of ferromanganese, the temperature of molten steel is lost. When LF is refined, it takes a long time to heat up, and the power consumption and electrode consumption are large, and the cost increases.
At the same time, since manganese is an element that is easy to segregate, when the manganese content is high, it is easy to cause manganese segregation, which will have a negative impact on the internal quality of steel billets and steel plates
[0004] In the subsequent rolling process, the conventional process generally adopts a two-stage controlled rolling and controlled cooling process. The recrystallization stage generally ends above 960°C. The second stage is the non-recrystallized controlled rolling stage. The rolling start temperature generally requires below 890°C. As a result, the intermediate billet is cooled by air cooling on the roller table, and this process seriously affects the rolling rhythm
For this reason, many medium and heavy plate factories have taken many measures such as reducing the thickness of the intermediate billet, increasing the number of intermediate billets, using water cooling in the waiting area, and increasing the bypass roller table, but these have relatively large limitations and cannot be fundamentally Eliminate the impact of air-drying steel waiting temperature on production rhythm

Method used

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  • Titanium microalloyed Q355B structural steel plate and recrystallization controlled rolling process method thereof
  • Titanium microalloyed Q355B structural steel plate and recrystallization controlled rolling process method thereof
  • Titanium microalloyed Q355B structural steel plate and recrystallization controlled rolling process method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] The chemical composition of the steel plate in this example is C: 0.18%, Si: 0.19%, Mn: 0.72%, P: 0.017%, S: 0.008%, Als: 0.028%, Ti: 0.059%, Ceq: 0.30%.

[0040] According to above-mentioned chemical composition range, the technological process of the present embodiment is as follows:

[0041] After the iron ore is smelted into molten iron in the blast furnace, the molten iron is pre-desulfurized so that the S in the molten iron is ≤0.006%;

[0042] Blowing in a 120t converter, the end temperature of the converter is 1658°C, the LF entry temperature is 1540°C, 220 meters of aluminum wire is fed, after adding ferro-titanium 3.2Kg / t steel, the soft blowing time is 8 minutes and 21 seconds, and the calcium wire is fed 200m, the exit temperature is 1560°C, the exit Ti content is 0.063%, and the S content is 0.007%;

[0043]The temperature of the molten steel continuous casting tundish is 1537°C (liquidus line is 1515°C), the superheat of the tundish is controlled between ...

Embodiment 2

[0054] The chemical composition of the steel plate in this example is C 0.17%, Si 0.23%, Mn 0.78%, P 0.016%, S 0.005%, Als 0.039%, Ti 0.067%, Ceq 0.29%.

[0055] According to above-mentioned chemical composition range and technological process, the technological process of the present embodiment is as follows:

[0056] After the iron ore is smelted into molten iron in the blast furnace, the molten iron is pre-desulfurized so that the S in the molten iron is ≤0.006%;

[0057] Blowing in a 120t converter, the end temperature of the converter is 1651°C, the LF entry temperature is 1538°C, the aluminum wire is fed 220 meters, after adding titanium iron 3.2Kg / t steel, the soft blowing time is 8 minutes and 24 seconds, and the calcium wire is fed 200m, the exit temperature is 1556°C, the exit Ti content is 0.071%, and the S content is 0.004%;

[0058] The temperature of the molten steel continuous casting tundish is 1534°C (liquidus line is 1515°C), the superheat of the tundish is ...

Embodiment 3

[0068] The chemical composition of the steel plate in this example is C: 0.18%, Si: 0.20%, Mn: 0.82%, P: 0.012%, S: 0.004%, Als: 0.032%, Ti: 0.062%, Ceq: 0.32%.

[0069] According to above-mentioned chemical composition range and technological process, the technological process of the present embodiment is as follows:

[0070] After the iron ore is smelted into molten iron in the blast furnace, the molten iron is pre-desulfurized so that the S in the molten iron is ≤0.006%;

[0071] Blowing in a 120t converter, the end temperature of the converter is 1658°C, the LF entry temperature is 1545°C, the aluminum wire is fed 225 meters, after adding ferro-titanium 3.1Kg / t steel, the soft blowing time is 8 minutes and 17 seconds, and the calcium wire is fed 200m, the exit temperature is 1562°C, the exit Ti content is 0.068%, and the S content is 0.004%;

[0072] The temperature of the molten steel continuous casting tundish is 1538°C (liquidus line is 1515°C), the superheat of the tu...

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Abstract

The invention belongs to the technical field of medium plate production, and particularly relates to a titanium microalloyed Q355B structural steel plate and a recrystallization controlled rolling process method thereof. The steel plate comprises the following chemical components in percentage by mass: 0.16 to 0.20 percent of C, 0.15 to 0.30 percent of Si, 0.70 to 0.90 percent of Mn, less than or equal to 0.025 percent of P, less than or equal to 0.015 percent of S, 0.015 to 0.045 percent of Als, 0.055 to 0.070 percent of Ti and the balance of Fe and inevitable impurities. The process method comprises the steps of blast furnace molten iron smelting, molten iron pre-desulfurization, converter smelting, deoxidation alloying, LF refining furnace refining, slab continuous casting, slab reheating, rolling mill rolling, laminar cooling, steel plate straightening, finished product sampling inspection and warehousing. The recrystallization controlled rolling process is adopted in the rolling stage, conventional two-stage controlled rolling is not adopted, temperature holding after first-stage rolling is avoided, and the production rhythm is high.

Description

technical field [0001] The invention belongs to the technical field of medium and heavy plate production, and in particular relates to a titanium microalloyed Q355B structural steel plate and a recrystallization controlled rolling process method thereof. Background technique [0002] Q355B structural steel plate is currently the most used medium and heavy plate for steel structure manufacturing, with an annual production and sales volume of more than 30 million tons. It is a product that can be mass-produced by all medium and heavy plate factories. [0003] According to the conventional production process, the C-Mn composition system is generally used, and the manganese content is about 1.40%. During the alloying process after converter smelting, due to the addition of a large amount of ferromanganese, the temperature of molten steel is lost. During LF refining, it takes a long time to raise the temperature, which leads to high power consumption and electrode consumption, an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/14C21D8/02C22C33/04
CPCC22C38/02C22C38/04C22C38/06C22C38/14C22C33/04C21D8/0205C21D8/0226C21D8/0263
Inventor 徐洪庆张楠李文双楚志宝王佩鑫
Owner 天津市新天钢钢铁集团有限公司
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