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

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...

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

Images