Optimal controlled rolling method adopting ultra-fast cooling to control Austenite structure

A technology of ultra-fast cooling and optimized control, which is applied in the field of steel materials to achieve the effect of improving performance

Active Publication Date: 2014-12-24
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is to solve the problem that the current ultra-rapid cooling technology is mainly applied to the coolin...

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  • Optimal controlled rolling method adopting ultra-fast cooling to control Austenite structure
  • Optimal controlled rolling method adopting ultra-fast cooling to control Austenite structure
  • Optimal controlled rolling method adopting ultra-fast cooling to control Austenite structure

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Experimental program
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Effect test

Embodiment 1

[0024] The chemical composition of bainitic steel for rolling is as follows: C: 0.04-0.06%, Si: 0.30-0.50%, Mn: 1.40-1.80%, P: ≤0.01%, S: ≤0.005%, Al: ≤0.03%, Ni: 0.20~0.40%, Cr: 0.40~0.60%, Cu: 0.30~0.50%, Ti: 0.02~0.03%, Nb: 0.03~0.05%, Mo: 0.15~0.18%, the balance is Fe And unavoidable impurities, the specific data are shown in Table 1.

[0025] After testing, the RLT of the bainite steel with the above composition is 990-1020°C; reheat the billet to 1200-1250°C and keep it warm for 1-2h, and carry out controlled rolling and controlled cooling on a 450mm two-roll hot rolling mill; The rolling temperature is 1150±10°C, the final rolling temperature is 1050±10°C, ultra-rapid cooling is adopted immediately after rolling, the cooling rate is 75±5°C / s, the steel plate is cooled to 400°C, and then air-cooled to room temperature, the typical steel plate Austenitic structure such as figure 1 As shown, the typical tissue characteristics at room temperature are as follows figure 2...

Embodiment 2

[0045] The chemical composition (mass fraction) of ferritic steel for rolling is: C: 0.05-0.07%, Si: 0.25-0.35%, Mn: 1.20-1.50%, P: ≤0.008%, S: ≤0.005%, Al : ≤0.06%, Ti: 0.09-0.12%, V: 0.05-0.07%, and the balance is Fe and unavoidable impurities. The specific data are shown in Table 6.

[0046] After testing, the RLT of the ferritic steel with the above composition is 960-1010°C; reheat the billet to 1200-1250°C and keep it warm for 1-2 hours, and carry out controlled rolling and controlled cooling on a 450mm two-roll hot rolling mill; The rolling temperature is 1155±5°C, and the final rolling temperature is 1030±5°C. Immediately after rolling, the steel plate is cooled to 700°C by ultra-rapid cooling at a cooling rate of 55±5°C / s, and then air-cooled to room temperature. body structure such as image 3As shown, the TEM morphology is as follows Figure 4 shown.

[0047] The controlled rolling process is shown in 7, and the mechanical properties are shown in Table 8.

[004...

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Abstract

At present, an ultra-fast cooling technology is mainly applied to cooling of steel after two-stage controlled rolling. The invention discloses an optimal controlled rolling method adopting ultra-fast cooling to control an Austenite structure and belongs to the technical field of metallurgy. According to the method, the steel can be completely rolled in a steel billet Austenite recrystallization zone, rolling temperature and pass reduction rate can be simultaneously precisely controlled, an ultra-fast cooling system is immediately adopted to cool the rolled steel to a phase transition point after rolling, and then different cooling paths are adopted according to needs to control the phase transition of the steel. According to the method disclosed by the invention, the ultra-fast cooling is adopted, so that coarsening of the small re-crystallized Austenite structure can be effectively inhibited, and the refining effects of dynamic recrystallization and sub-dynamic recrystallization against the Austenite structure in a high-temperature rolling process can be retained. The product manufactured by the method disclosed by the invention and the steel manufactured by the two-stage controlled rolling process have equivalent mechanical properties, so that the rolling time is simultaneously reduced by 2-4min in comparison with the two-stage controlled rolling process at a waiting temperature and low-temperature atmosphere in the rolling process.

Description

technical field [0001] The invention belongs to the technical field of iron and steel materials, and in particular relates to an optimally controlled rolling method for controlling austenite structure by ultra-rapid cooling. Background technique [0002] Controlled rolling and controlled cooling technology (Thermomechanical Control Process, TMCP) is one of the greatest achievements in the steel industry in the 20th century. Since the 1950s, TMCP technology has played a pivotal role in improving the comprehensive performance of hot-rolled products. The core features of the traditional TMCP technology are: ① "Low temperature and large reduction" and "addition of microalloying elements" to obtain hardened austenite to the greatest extent; ② Accelerated cooling after rolling (Accelerated Cooling, ACC), controlled hardening of austenite phase transition, refine the structure. [0003] Japan's JFE Company developed the accelerated cooling process before other steel companies, and...

Claims

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Application Information

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IPC IPC(8): C21D8/00
Inventor 陈俊刘振宇唐帅王国栋
Owner NORTHEASTERN UNIV
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