V-N microalloying 460MPa-level thick plate and manufacturing method thereof

Abstract

The invention discloses a V-N microalloying 460MPa-level thick plate, comprising the following elements by weight percent: 0.05-0.1% of C, 0.1-0.3% of Si, 1.61-2.1% of Mn, no more than 0.015% of P, no more than 0.07% of S, 0.01-0.05% of V, 0.01-0.03% of Ti, 0.008-0.015% of N, 0.01-0.05% of Als, the balance of Fe and inevitable impurities, wherein nitrogen is bottom blown by a converter in the whole process; the flow is 5-40 Nm<3 / min; the time is 5-30 minutes; the nitrogen is blow by an oxygen lance for 5-30 minutes after the gun is lifted; ferrovanadium is added after LF refining; an RH (rhodium) lift gas is nitrogen; the flow is 100-300 Nm<3> / h; the time is 10-60 minutes; the heating temperature of a blank is 1150-1250 DEG C; the heat preservation time is 100-300 minutes; the rolling temperature is 1050-1150 DEG C; the pass deformation rate is 15-35%; the finishing temperature is 800-970 DEG C; and the temperature is reduced to 500-700 DEG C at the speed of 10-30 DEG C / s. The production efficiency is improved; the material cost and the production cost are reduced; and various specifications of thick steel plates, of which the thicknesses are 10-100 mm and the overall compression ratio is 4 at least can be prepared.

Description

technical field [0001] The invention belongs to the field of low-alloy steel production, and relates to a thick plate with a yield strength of 460 MPa, low welding sensitivity, high strength and toughness and a manufacturing method thereof. Background technique [0002] At present, the production of 460MPa high-strength low-alloy steel plates at home and abroad mainly adopts Nb microalloying, and is produced by controlled rolling and controlled cooling. For example, in 2010, Nanyang Hanye Special Steel Co., Ltd. applied for a patent of CN201010597667.6 for the patent "low-alloy high-strength steel plate Q460C and its manufacturing method" and for a patent of CN201010597658.7 for a patent "low-alloy high-strength steel plate Q460E-Z35 and its manufacturing method" , all adopt V-Ti-Nb microalloying, billet heating temperature 1240 ℃, two-stage controlled rolling, final rolling temperature ≤ 860 ℃. Similarly, Nippon Steel Corporation's application number is CN01801553.0 patent...

AI Technical Summary

Problems solved by technology

This method adds a variety of smelting raw materials whose yields are difficult to control at the same time, which not only has high costs, but also increases the difficulty of controlling V elements and N elements in the smelting process.

And application number is CN02104447.3 patent " microalloying high-strength low-alloy steel with nitrogen-rich and vanadium-containing alloys and its smelting method " adopts a kind of Si3N4 is the nitrogen-rich alloy of matrix production and the steel that the intensity level of the present invention is close First, the amount of steel to be added is 0.8-4 kg per ton, and the method is to add it by bagging precipitation when tapping 1 / 6-4 / 5, and add vanadium-containing alloy at the same time, blowing argon and stirring weakly during the tapping process, obviously this kind The cost of the method is high, and the process is extremely difficult to control precisely

[0004] The problems reflected in the above-mentioned invention roughly include the following four aspects: 1. The use of precious metal Nb for microalloying has high alloy cost and unstable microstructure and performance control; 2. The use of precious metal Nb for microalloying requires high billet heating temperature. Large energy consumption; 3. The use of noble metal Nb for micro-alloying has many control factors in the subsequent rolling process, which is difficult to control and has low production efficiency; 4. The micro-alloying process of adding V-N alloys and nitrogen-enhancing agents is adopted. The cost of raw materials is high, the smelting control factors are many and the empirical component is large, and the N yield is unstable and difficult to control

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