Production method of superthick steel plate by using continuous casting billet in condition of small compression ratio

Abstract

The invention provides a production process of a superthick steel plate by using continuous casting billet in a condition of a small compression ratio. The method comprises the following steps: smelting process, wherein a converter is adopted for smelting, micro-alloy elements Nb and Ti are added by virtue of LF (ladle furnace) and RH (Ruhrstahl-Heraeus) refining for micro-alloying, performing full-protective casting, and discharging and slowly cooling the continuous casting billet for over 48 hours; heating process, wherein the heating temperature is between 1180 and 1220 DEG C, the reference time of heating is between 8 and 10 min / cm to ensure that the billet is uniformly and completely burned, and the soaking time is not less than 40 minutes; rolling process, wherein a dual-frame two-stage controlled rolling process is adopted, a rough mill performs complete recrystallization rolling at a temperature of more than or equal to 1000 DEG C, a thickness is more than or equal to 1.2 times the thickness of a finished product, the initial rolling temperature of finish rolling is controlled to be between 880 and 850 DEG C, the steel plate is instantly subjected to rapid cooling after rolling, the cooling speed is between 5 and 7 DEG C / s, and the finish cooling temperature is controlled to be between 630 and 600 DEG C; and normalizing heat treatment process, wherein the normalizing treatment temperature is between 890 and 860 DEG C, the temperature preservation time in the furnace is between 1.5 and 2.0 min / mm, the normalized steel plate is singly flattened in a ventilated place after discharged, and the collecting temperature of the steel plate is less than or equal to 100 DEG C.

Description

technical field [0001] The present invention relates to the technical field of rolling and heat treatment processes for producing extra-thick steel plates by using continuous casting slabs, and more specifically, relates to a production process for using continuous casting slabs to produce extra-thick plates with high toughness and resistance to layered tearing. A simple and feasible technological approach is provided for producing steel plates with thicker specifications by using a continuous casting slab with a certain thickness. Background technique [0002] At present, some enterprises at home and abroad mostly use large steel ingots or compound rolling methods to produce steel plates with a thickness of more than 100 mm, resulting in low yield or long production cycle. Continuous casting slabs are directly rolled to produce thick-gauge steel plates, which can overcome the shortcomings of low yield or long production cycle, but due to the limitation of compression ratio,...

AI Technical Summary

Problems solved by technology

This patent uses 250-300mm continuous casting slabs to produce 40-100mm steel plates, the compression ratio is not less than 3.0, and the thickness of the steel plates is not large; and the chemical composition of the steel plates contains expensive Ni elements, which relatively increases the cost of the steel plates

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