Method for preparing hot-rolled double-phase steel by front super-quick cooling process

Abstract

The invention belongs to the technical field of steel rolling and particularly relates to a method for preparing hot-rolled double-phase steel by a front super-quick cooling process. The method is realized through the technical scheme which comprises the following steps of: heating a continuous casting blank in a tunnel kiln, wherein the heating temperature is controlled to be between 1,150 and 1,200 DEG C, the heating time is controlled to be 120 minutes, and the kiln outlet temperature is controlled to be between 1,100 and 1,150 DEG C; rolling the continuous casting blank which is discharged from the kiln on a hot continuous rolling machine set, wherein the crude rolling machine inlet temperature is controlled to be between 1,000 and 1,100 DEG C, the precision rolling temperature is controlled to be between 950 and 990 DEG C, and the final rolling temperature is controlled to be between 800 and 830 DEG C; and after hot rolling, controlling cooling, performing super-quick cooling on the continuous casting blank to reduce the temperature to 110 to 130 DEG C at the cooling speed of 100 to 140 DEG C / second, performing air cooling on the continuous casting blank for 2 to 6 seconds, performing laminar cooling on the continuous casting blank to 100 to 240 DEG C to coil the continuous casting blank, and thus obtaining a steel plate of which the thickness is 2.75 to 4.7mm. The traditional rear super-quick cooling process for producing the double-phase steel is changed by the technical scheme. Front super-quick cooling equipment existing in industrial production is utilized, so that improvement on cooling equipment is avoided, and the performance of the front super-quick cooling equipment completely meets the requirements of users.

Description

technical field [0001] The invention belongs to the technical field of steel rolling, and in particular relates to a method for preparing hot-rolled dual-phase steel by pre-type ultra-fast cooling. Background technique [0002] Since the advent of dual-phase steel in the 1960s, it has played an important role in the lightweight of automobile structures. Due to its low cost and good performance, the application of hot-rolled dual-phase steel on automobile body-in-white has reached 75-80%. [0003] Since dual-phase steel has the characteristics of martensite and ferrite at the same time, the technical difficulties that need to be overcome in the production process are: 1) to generate enough ferrite; 2) to suppress the generation of pearlite; 3) to suppress the pearlite 4) Retained austenite is transformed into martensite, which requires the addition of alloying elements and post-type rapid cooling, that is, first laminar cooling, and finally ultra-rapid cooling to suppress bai...

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Problems solved by technology

[0004] However, in industrial production, a steel production line often produces different types of steel. In order to save costs and adapt to the production of most steel products, ultra-fast cooling equipment is usually built behind the rolling mill and before the laminar cooling zone. Such a production line does not It is suitable for the production of dual-phase steel, or it is necessary to modify the cooling equipment to produce dual-phase steel, which undoubtedly increases the difficulty of production and production costs for enterprises. At the same time, the current rise in international ferromolybdenum prices also brings Huge cost pressure, urgent need to develop a cost-effective dual-phase steel production process

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