Method for producing 23MnB steel by adopting vacuum process

Abstract

The invention discloses a method for producing 23MnB steel by adopting a vacuum process and belongs to the field of ferrous metallurgy. The invention aims at solving the technical problem of providing a method for producing 23MnB steel by smooth casting with a large-size continuous casting machine. The method comprises the following steps of: a, smelting in a converter; b, when steel tapping, adding calcium carbide in molten steel and then adding aluminum, so that the weight percentage content of acid-soluble aluminum in the molten steel is between 0.014% and 0.019%; c, refining in an LF (ladle furnace); d, after refining, carrying out vacuum circulation treatment, wherein in the treatment, aluminum is added into the molten steel so that the content of acid-soluble aluminum is 0.025-0.055%, titanium is added so that the content of titanium is 0.02-0.06%, and boron is added so that the content of boron is 0.0005-0.003%; and e, continuously casting. According to the invention, the content of acid-soluble aluminum is strictly controlled from various steps, the yield of boron is high, the hardenability of the 23MnB steel is good, and the water gap of the large-size continuous casting machine is prevented from being dwindled.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy, and in particular relates to a method for producing 23MnB steel by a vacuum method. Background technique [0002] A small amount of boron (about 0.001%) can be adsorbed on the austenite grain boundary, reduce the grain boundary energy, inhibit the formation of ferrite nuclei, and double the hardenability of medium and low carbon steels. Therefore, medium and low carbon steels often Add 0.0005-0.003% trace amount of boron to improve hardenability of steel. However, boron is one of the most 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 role. [0003] Existing studies have shown that boron has a strong affinity with oxygen and nitrogen, and boron is easily oxidized to generate B 6 O or B 2 o 3 , or combined with nitrogen to form BN, these are harmful substanc...

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.