阅读说明：本技术 一种降低真空脱碳钢种转炉出钢温度的炼钢方法 (Steelmaking method for reducing tapping temperature of vacuum decarburization steel converter ) 是由 乌力平 李应江 徐小伟 邓勇 李宝庆 胡晓光 于 2019-11-18 设计创作，主要内容包括：本发明公开了一种降低真空脱碳钢种转炉出钢温度的炼钢方法,将转炉出钢温度控制在1630℃以下；出钢结束向钢包中加入2-10kg/t钢铝型、硅型或铝硅型金属升温剂；钢水在真空处理初期通过顶枪向真空室内吹入氧气以完成升温操作,吹氧量(Nm<Sup>3</Sup>)＝A+B+C+D；真空精炼过程调整温度需补充的升温剂或冷却废钢在明显开始脱碳前加入；真空脱碳钢种的重量百分比组成为：碳：≤0.035％；RH吹氧结束后的脱碳、脱氧及合金化的操作方法同钢厂现行方法相同。针对真空脱碳钢种,能够显著的降低转炉出钢温度,解决转炉冶炼真空脱碳钢种高温出钢带来的一系列的负面影响问题。(The invention discloses a steelmaking method for reducing the tapping temperature of a converter of vacuum decarburization steel grade, which controls the tapping temperature of the converter to be below 1630 ℃; adding 2-10kg/t of steel aluminum type, silicon type or aluminum silicon type metal heating agent into the steel ladle after tapping; blowing oxygen into the vacuum chamber through the top lance to complete the heating operation at the initial stage of vacuum treatment, and blowing oxygen amount (Nm) 3 ) A + B + C + D; adding a heating agent or cooling steel scrap to be supplemented for adjusting the temperature in the vacuum refining process before obviously beginning decarburization; the vacuum decarburization steel grade comprises the following components in percentage by weight: carbon: less than or equal to 0.035%; the operation methods of decarburization, deoxidation and alloying after RH oxygen blowing are the same as the current method of steel mill. For vacuum decarburization steel grade, can showThe tapping temperature of the converter is obviously reduced, and a series of negative effects caused by high-temperature tapping of vacuum decarburization steel grades in converter smelting are solved.)

1. A steelmaking method for reducing the tapping temperature of a vacuum decarburization steel type converter is characterized by comprising the following steps:

s1: controlling the tapping temperature of the converter below 1630 ℃;

s2: adding 2-10kg/t of steel aluminum type, silicon type or aluminum silicon type metal heating agent into the steel ladle after tapping;

s3: blowing oxygen into the vacuum chamber through the top lance to complete the heating operation at the initial stage of vacuum treatment, and blowing oxygen amount (Nm)³) A + B + C + D, wherein a: oxidizing the oxygen blowing amount of the residual heating agent of the molten steel; b: oxygen blowing amount of molten steel temperature compensation; c: the blowing oxygen amount for molten steel decarburization is met; d: the oxygen blowing amount of the excess oxygen amount matched with the target carbon content when the decarburization of the molten steel is finished is met;

s4: adding a heating agent or cooling steel scrap to be supplemented for adjusting the temperature in the vacuum refining process before obviously beginning decarburization;

s5: the vacuum decarburization steel grade comprises the following components in percentage by weight: carbon: less than or equal to 0.035%;

s6: the operation methods of decarburization, deoxidation and alloying after RH oxygen blowing are the same as the current method of steel mill.

2. The steel-making method for reducing the converter tapping temperature of the vacuum decarburization steel grade as claimed in claim 1, wherein the converter tapping temperatures are controlled to 1621 ℃, 1618 ℃, 1624 ℃ and 1617 ℃ in S1, respectively.

3. The steel-making method for lowering tapping temperature of a converter of vacuum decarburization steel grade as claimed in claim 1, wherein 4.5kg/t steel, 5.2kg/t steel, 3.9kg/t steel and 6.4kg/t steel of aluminum type exothermic compositions are charged into the ladle at the end of tapping at S2.

4. The steel-making method for lowering tapping temperature of a converter of vacuum decarburization steel grade as claimed in claim 1, wherein the RH oxygen blowing amount in S3 is 455Nm each³、434Nm³、579Nm³、580Nm³。

Technical Field

The invention relates to the technical field of steel making and external refining, in particular to a steel making method for reducing the tapping temperature of a vacuum decarburization steel converter.

Background

The converter tapping temperature is greatly related to the consumption of iron and steel materials and the consumption of alloy materials and refractory materials in the steelmaking process, and has important influence on the quality of molten steel and the steelmaking production efficiency. For low-carbon and ultra-low-carbon steel which needs refining and vacuum decarburization, because the decarburization process is long in time, the heat taken away by vacuum treatment is large, and a large temperature compensation means is not provided generally, a method of high-temperature tapping of a converter is often adopted to make up for the temperature loss in the refining process. Generally, the higher the converter tapping temperature is, the more oxygen content in the steel will be. On one hand, the dosage of the alloy deoxidizer is increased when the converter taps at high temperature, the excessive oxygen causes the increase of the deoxidized products and the increase of the inclusions in the steel; meanwhile, the overhigh tapping temperature is not beneficial to the dephosphorization of the converter, so that the consumption of the steelmaking flux is increased; on the other hand, high tapping temperatures lead to increased losses of the converter iron. In addition, the high-temperature tapping also causes the consumption of the refractory material of the furnace lining to rise, the service life of the converter to decrease, the maintenance time of the furnace lining to increase and the production efficiency to be seriously influenced.

In view of a series of adverse effects caused by the high tapping temperature of a vacuum decarburization steel type converter, a great deal of research has been conducted by industry for a long time, and in addition to developing a technique for reducing the tapping temperature to a certain extent by reducing the process temperature loss through heat storage and heat preservation, rapid turnover, and the like, a so-called chemical method, in which the tapping temperature of a converter is reduced to a certain extent, is adopted by raising the temperature of molten steel by adding a heat generating element such as silicon or aluminum and blowing oxygen into the molten steel during vacuum refining. However, generally, because the temperature raising agent is added later, even if the temperature raising amplitude is still unsatisfactory, the existing temperature raising process method has a great negative effect on the quality of the steel.

However, for various reasons, there has been no method developed in history that can significantly reduce the converter tapping temperature of the vacuum decarburization steel grade. For example, the latest scientific article "practice of reducing tapping temperature of converter" (steel making: 10 th 2018): the tapping temperature is reduced by adopting ladle capping and improving the pulling speed of a casting machine to shorten the casting period, and is reduced from 1688 ℃ in 2015 to 1655 ℃ in 2018; scientific article practice of reducing tapping temperature of converter (Shandong metallurgy: No. 6 of 2010): the heat conductivity coefficient of the packing is reduced and the heat loss of the packing is reduced by 1) optimizing the way of the insulating layer of the steel ladle; 2) the measures of baking the alloy improve the temperature of the alloy before adding the alloy into molten steel; 3) and (3) after the continuous casting process, covering and insulating the ladle, protecting and pouring in the whole process, and reducing the average tapping temperature of the converter by more than 20 ℃ by adopting measures such as an alkaline tundish covering agent and the like.

Chinese patent (application publication No. CN 109487034A) discloses 'a method for producing IF steel by composite deoxidation', and the invention refers to: when steel is smelted in a converter, the tapping temperature is 1695-1720 ℃; bottom-blown stirring during tapping, but no specific measures are mentioned to reduce the tapping temperature of the converter. Chinese patent (application publication No. CN 106319132 a) discloses "a method for controlling sulfur content in steel", which mentions: the tapping temperature of the converter is 1650-1680 ℃, but specific measures for reducing the tapping temperature of the converter are not mentioned. Chinese patent (application publication No. CN 106811685A) discloses a method for smelting low-carbon high-manganese steel, which refers to the following steps: the tapping temperature of the converter is controlled to be 1660-1680 ℃, but specific measures for reducing the tapping temperature of the converter are not mentioned.

The above published converter and scientific and technical papers show that the reduction of tapping temperature is mainly achieved by means of steel ladle capping, improvement of a steel ladle heat-insulating layer, shortening of casting period, roasting of alloy and other measures, and most of the measures need equipment modification; meanwhile, the tapping temperature of the converter in the steel mill is still higher at present, and the control range is 1650-1720 ℃. In view of the above, it is important to develop a control method for reducing the tapping temperature of a vacuum decarburization steel converter.

Disclosure of Invention

The invention aims to provide a steelmaking method for reducing the tapping temperature of a converter of vacuum decarburization steel grade, and provides a steelmaking method for reducing the tapping temperature of the converter with the upper limit of the tapping temperature of the converter not exceeding 1630 ℃ aiming at the vacuum decarburization steel grade and adding a heating agent after tapping so as to reduce the tapping temperature of the converter with the chemical heating reaction outside the converter as early as possible, thereby obviously reducing the tapping temperature of the converter and solving a series of negative influence problems caused by high-temperature tapping of the converter smelting vacuum decarburization steel grade.

In order to achieve the purpose, the invention provides the following technical scheme:

a steelmaking method for reducing the tapping temperature of a vacuum decarburization steel type converter comprises the following steps:

s1: controlling the tapping temperature of the converter below 1630 ℃;

s2: adding 2-10kg/t of steel aluminum type, silicon type or aluminum silicon type metal heating agent into the steel ladle after tapping;

s3: blowing oxygen into the vacuum chamber through the top lance to complete the heating operation at the initial stage of vacuum treatment, and blowing oxygen amount (Nm)³) A + B + C + D, wherein a: oxidizing the oxygen blowing amount of the residual heating agent of the molten steel; b: oxygen blowing amount of molten steel temperature compensation; c: the blowing oxygen amount for molten steel decarburization is met; d: the oxygen blowing amount of the excess oxygen amount matched with the target carbon content when the decarburization of the molten steel is finished is met;

s4: adding a heating agent or cooling steel scrap to be supplemented for adjusting the temperature in the vacuum refining process before obviously beginning decarburization;

s5: the vacuum decarburization steel grade comprises the following components in percentage by weight: carbon: less than or equal to 0.035%;

s6: the operation methods of decarburization, deoxidation and alloying after RH oxygen blowing are the same as the current method of steel mill.

Further, in S1, the tapping temperature of the converter was controlled to 1621 deg.C, 1618 deg.C, 1624 deg.C, and 1617 deg.C, respectively.

Further, 4.5kg/t steel, 5.2kg/t steel, 3.9kg/t steel, and 6.4kg/t steel, respectively, of an aluminum type exothermic agent was added to the ladle at the end of tapping in S2.

Further, the RH oxygen blowing amount in S3 was 455Nm each³、434Nm³、579Nm³、580Nm³。

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a steelmaking method for reducing the tapping temperature of a converter of vacuum decarburization steel grade, which aims at the vacuum decarburization steel grade, provides that the upper limit of the tapping temperature of the converter is not more than 1630 ℃, and a heating agent is added after tapping, so that the external chemical heating reaction is furthest advanced to reduce the tapping temperature of the converter, and a series of negative influence problems caused by high-temperature tapping of the converter smelting vacuum decarburization steel grade are solved.

Drawings

FIG. 1 is a flow chart of a control method of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, in the embodiment of the present invention: the steelmaking method for reducing the tapping temperature of the vacuum decarburization steel type converter is provided, and comprises the following steps:

the first step is as follows: controlling the tapping temperature of the converter below 1630 ℃;

the second step is that: adding 2-10kg/t of steel aluminum type, silicon type or aluminum silicon type metal heating agent into the steel ladle after tapping;

the third step: blowing oxygen into the vacuum chamber through the top lance to complete the heating operation at the initial stage of vacuum treatment, and blowing oxygen amount (Nm)³) A + B + C + D, wherein a: oxidizing the oxygen blowing amount of the residual heating agent of the molten steel; b: oxygen blowing amount of molten steel temperature compensation; c: the blowing oxygen amount for molten steel decarburization is met; d: the oxygen blowing amount of the excess oxygen amount matched with the target carbon content when the decarburization of the molten steel is finished is met;

the fourth step: adding a heating agent or cooling steel scrap to be supplemented for adjusting the temperature in the vacuum refining process before obviously beginning decarburization;

the fifth step: the vacuum decarburization steel grade comprises the following components in percentage by weight: carbon: less than or equal to 0.035%;

and a sixth step: the operation methods of decarburization, deoxidation and alloying after RH oxygen blowing are the same as the current method of steel mill.

In order to better explain the invention, the technical scheme and the effect of the invention are described in detail by taking a 300-ton converter and a 300-ton RH furnace for smelting vacuum decarburization steel grades as examples: