Method for producing 23MnB steel in converter process

Abstract

The invention discloses a method for producing 23MnB steel in a converter process, belonging to the field of ferrous metallurgy, and aiming to solve the technical problem of providing a method for producing the 23MnB steel through smooth casting of a large-scale continuous casting machine while the hardenability of boron-containing steel is guaranteed. The method comprises the following steps: a,smelting in a converter; b, adding calcium carbide and aluminum into molten steel when the steel is discharged, so that the weight percentage of acid-soluble aluminum in the molten steel is 0.014-0.019 percent; c, stopping heating when the temperature of the molten steel is 1570-1585 DEG C during refining, adding the aluminum into the molten steel so that the content of the acid-soluble aluminum is 0.025-0.055 percent, adding titanium so that the titanium content is 0.02-0.06 percent, and adding boron so that the boron content is 0.0005-0.003 percent; and d, casting continuously. The content of the acid-soluble aluminum is controlled in each step, the hardenability of the boron-containing steel is good, and the water port of the large-scale continuous casting machine can be prevented frombecoming smaller.

Description

Technical field [0001] The invention belongs to the field of iron and steel metallurgy, and specifically relates to a method for producing 23MnB steel in a converter process. Background technique [0002] A small amount of boron (about 0.001%) can be adsorbed on austenite grain boundaries, reduce grain boundary energy, inhibit the formation of ferrite crystal nuclei, and double the hardenability of medium and low carbon steels. Therefore, medium and low carbon steels often Add 0.0005 to 0.003% of trace boron to improve the hardenability of steel. However, boron is one of the extremely active elements, which can form stable inclusions with residual oxygen and nitrogen in steel, and lose its beneficial effect. Only boron in solid solution can play a beneficial effect. [0003] Existing studies have shown that boron has a strong affinity with oxygen and nitrogen, and boron is easily oxidized to form B 6 O or B 2 O 3 , Or combined with nitriding to generate BN, these are harmful subst...

AI Technical Summary

Problems solved by technology

In order to ensure the role of boron in improving hardenability, this patent adds aluminum and refining slag to deoxidize molten steel and steel slag after tapping out of the converter, and controls the acid-soluble aluminum in molten steel to be in the range of 0.02% to 0.04%. Aluminum is added to the water to ensure the yield of boron and the hardenability of boron-containing steel. However, this patent does not take into account the impact of adding aluminum on the continuous casting of the continuous casting machine

The applicant found that part of the aluminum will be lost during the production of 23MnB steel, and the content of aluminum is not easy to control, and some of the aluminum will be oxidized to Al 2 o 3 , these Al 2 o 3 It will make the nozzle of the continuous casting machine crystallizer smaller and the flow rate of molten steel decrease, which will affect the continuous casting and bring great difficulties to the control of the continuous casting machine. In serious cases, it will even block the nozzle of the continuous casting machine and cause a safety accident.