阅读说明：本技术 一种保碳脱磷的转炉补吹炼钢方法 (Converter blowing-supplementing steelmaking method capable of protecting carbon and removing phosphorus ) 是由 许旭东 胡志勇 李林 鲁川 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种保碳脱磷的转炉补吹炼钢方法。属于转炉冶金领域,具体操作步骤：钢水氧含量测量及取样；辅原料加；高枪位补吹；倒出炉渣。本发明解决了传统补吹炼钢使用氧气低枪位补吹,在脱磷的同时,钢水中碳被继续氧化至较低水平,造成钢水氧含量增加和钢水中氧化性中夹杂物含量的进而影响钢材性能的问题。钢水碳含量较补吹前碳含量降低不大于0.04％,且可稳定维持在0.08％以上；另外,在补吹后钢水氧含量增加值不大于100ppm,减少钢水碳含量低对转炉镁碳质耐火材料的侵蚀,保证补吹的炉衬安全性；且不会造成钢水中氮含量增加,钢材的时效性能和造成蓝脆无不良影响。(The invention discloses a converter blowing-supplementing steelmaking method for protecting carbon and removing phosphorus. Belongs to the field of converter metallurgy, and comprises the following specific operation steps: measuring and sampling the oxygen content of the molten steel; adding auxiliary raw materials; high lance position supplementary blowing; and pouring out the slag. The invention solves the problems that the oxygen content of the molten steel is increased and the content of impurities in oxidability in the molten steel further influences the performance of steel because carbon in the molten steel is continuously oxidized to a lower level while dephosphorization is carried out by using oxygen low lance position supplementary blowing in the traditional supplementary blowing steelmaking. The carbon content of the molten steel is reduced by not more than 0.04 percent compared with the carbon content before the complementary blowing, and can be stably maintained at more than 0.08 percent; in addition, the oxygen content increase value of the molten steel after the after-blowing is not more than 100ppm, the corrosion of the low carbon content of the molten steel to the magnesia-carbon refractory material of the converter is reduced, and the safety of a furnace lining of the after-blowing is ensured; and the nitrogen content in the molten steel can not be increased, and the aging performance and blue brittleness of the steel can not be influenced.)

1. The converter reblowing steelmaking method with carbon protection and dephosphorization is characterized by comprising the following specific operation steps:

(1) measuring the oxygen content of the molten steel and sampling: after the end point converting is finished, lifting the oxygen lance to a waiting position, measuring the oxygen content of the molten steel and sampling;

(2) adding auxiliary raw materials: adding lime and iron-containing raw materials into a converter;

(3) and high lance position supplement blowing: adjusting the lance position of the oxygen lance to the height of the liquid level of the molten steel, opening oxygen, supplying oxygen, and then closing the oxygen;

(4) and pouring out slag: and after the blowing is finished, deslagging, and measuring the oxygen content of molten steel and sampling after deslagging is finished.

2. The carbon-protecting and phosphorus-removing converter reblowing steel making method of claim 1,

in the step (2), the mass of the added lime is 2-6kg/t steel; the mass of the iron-containing raw material is 3-10kg/t steel.

3. The carbon-protecting and phosphorus-removing converter reblowing steel making method of claim 1,

in the step (2), the added iron-containing raw materials comprise sintered return ores, sludge balls and small pieces of scrap steel.

4. The carbon-protecting and phosphorus-removing converter reblowing steel making method of claim 1,

in the step (3), the height of the liquid level of the molten steel is 6000-10000 mm;

the oxygen supply intensity is controlled at 160-250m³Steel,/h.t; the oxygen supply time is 10-40 s.

5. The carbon-protecting and phosphorus-removing converter reblowing steel making method of claim 1,

and (4) after the completion of the blowing-in, waiting for 0-5min and then deslagging.

Technical Field

The invention belongs to the field of converter metallurgy, relates to a complementary blowing treatment process, and particularly relates to a steelmaking method for medium-high carbon steel grades by using oxygen complementary blowing, carbon-preserving and dephosphorization.

Background

In the prior art, the produced high-end steel grade is mainly high-end steel grade with medium-high carbon, low phosphorus and low nitrogen, but the phosphorus content of molten iron is higher to 0.12-0.15%, so that the requirement of the phosphorus content of molten steel at the end point of the converter on the super-grade steel is more prominent; the traditional steel-making method by blowing after supplement has the following problems: 1. the oxygen low lance position supplement blowing is used in the traditional supplement blowing steelmaking, carbon in molten steel is continuously oxidized to a lower level while dephosphorization is carried out, so that the oxygen content of the molten steel is increased, the quantity of oxidizing substances in the molten steel is greatly increased, the inclusion content in steel is further increased, and the performance of the steel is influenced; 2. the low carbon content of the molten steel can also corrode the magnesia-carbon refractory material of the converter, thus affecting the safety of the furnace lining and increasing the maintenance cost of the furnace lining; 3. the nitrogen is used for blowing in a supplementing way in the production process, and the defects that the nitrogen content in the molten steel is increased due to the use of the nitrogen, the aging performance of the steel is influenced, blue brittleness is caused, and high-end steel types are not paid. Therefore, it is necessary to develop an efficient converter reblowing steelmaking method with carbon and phosphorus conservation.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a converter reblowing steelmaking method of carbon-retaining dephosphorization by oxygen reblowing, which can effectively remove the phosphorus content in molten steel without obviously reducing the carbon content of the molten steel and increasing the oxidability of the molten steel, and can not increase the nitrogen content in the molten steel. .

The technical scheme is as follows: the invention relates to a converter after-blow steelmaking method with carbon-protecting and dephosphorization, which comprises the following specific operation steps:

(1) measuring the oxygen content of the molten steel and sampling: after the end point converting is finished, lifting the oxygen lance to a waiting position, measuring the oxygen content of the molten steel and sampling;

(2) adding auxiliary raw materials: adding lime and iron-containing raw materials into a converter;

(3) and high lance position supplement blowing: adjusting the lance position of the oxygen lance to the height of the liquid level of the molten steel, opening oxygen, supplying oxygen, and then closing the oxygen;

(4) and pouring out slag: and after the blowing is finished, deslagging, and measuring the oxygen content of molten steel and sampling after deslagging is finished.

Further, in the step (2), the mass of the added lime is 2-6kg/t steel; the mass of the iron-containing raw material is 3-10kg/t steel.

Further, in the step (2), the iron-containing raw materials include sintered return ores, sludge balls and small pieces of scrap steel.

Further, in the step (3), the height of the liquid level of the molten steel is 6000-10000 mm;

the oxygen supply intensity is controlled at 160-250m³Steel,/h.t; the oxygen supply time is 10-40 s.

Further, in the step (4), after the completion of the after-blowing, the slag is poured after waiting for 0-5 min.

Has the advantages that: compared with the prior art, the invention has the advantages that: 1. the problem that the oxygen content of molten steel is increased and the content of impurities in oxidability in the molten steel further influences the performance of steel due to the fact that carbon in the molten steel is continuously oxidized to a lower level while dephosphorization is carried out by using oxygen low lance position supplementary blowing in traditional supplementary blowing steelmaking is solved. The carbon content of the molten steel is reduced by not more than 0.04 percent compared with the carbon content before the complementary blowing, and can be stably maintained at more than 0.08 percent; 2. the oxygen content increase value of the molten steel after the reblowing is not more than 100ppm, the corrosion of the converter magnesia carbon refractory material due to low carbon content of the molten steel is reduced, and the safety of a furnace lining of the reblowing is ensured; 3. the nitrogen content in the molten steel can not be increased, and the aging performance and blue brittleness of the steel can not be influenced.

Drawings

FIG. 1 is a flow chart of the operation of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

As shown in fig. 1, the converter reblowing method with carbon retention and dephosphorization according to the present invention aims at the problems of high converter endpoint phosphorus, increased oxidative inclusion in molten steel during reblowing and decarburization, and the like, and provides a converter reblowing method with carbon retention and dephosphorization by improving the operation process of converter endpoint phosphorus high treatment, so as to effectively remove the phosphorus content in molten steel without significantly reducing the carbon content of molten steel and increasing the oxidability of molten steel; the method comprises the following specific operation steps of adding lime and iron-containing raw materials after the gun lifting is finished at the end point of converter blowing, and carrying out oxygen blowing at a high gun position and deslagging and then tapping:

(1) measuring the oxygen content of the molten steel and sampling: after the end point converting is finished, lifting the oxygen lance to a waiting position, measuring the oxygen content of the molten steel and sampling;

(2) adding auxiliary raw materials: adding lime and iron-containing raw materials into a converter;

(3) and high lance position supplement blowing: adjusting the lance position of the oxygen lance to the height of the liquid level of the molten steel, opening oxygen, supplying oxygen, and then closing the oxygen;

(4) and pouring out slag: and after the blowing is finished, deslagging, and measuring the oxygen content of molten steel and sampling after deslagging is finished.

Further, in the step (2), the mass of the added lime is 2-6kg/t steel; the mass of the iron-containing raw material is 3-10kg/t steel.

Further, in the step (2), the iron-containing raw materials include sintered return ores, sludge balls and small pieces of scrap steel.

Further, in the step (3), the height of the liquid level of the molten steel is 6000-10000 mm;

the oxygen supply intensity is controlled at 160-250m³Steel,/h.t; the oxygen supply time is 10-40 s.

Further, in the step (4), after the completion of the after-blowing, the slag is poured after waiting for 0-5 min.

Example 1

The invention discloses a converter reblowing steelmaking method with carbon and phosphorus protection, which comprises the following steps:

1. after the end point converting is finished, lifting the oxygen lance to a waiting position, and measuring the oxygen content of the molten steel 173ppm, the sampling carbon 0.167%, the phosphorus 0.0179% and the nitrogen content 23 ppm;

2. adding auxiliary raw materials: adding 2.1kg/t steel of lime and 4.8kg/t steel of sintered return ores into the converter;

3. high lance position supplement blowing: adjusting the lance position of the oxygen lance to 8100mm high of the liquid level of the molten steelThe oxygen is turned on, and the oxygen supply intensity is controlled at 200m³The steel is/h.t steel, oxygen is cut off after oxygen supply for 27 s;

4. pouring out slag: and after the blowing-up is finished, the slag is poured for 2min, and the oxygen content of molten steel is measured to be 214ppm, the sampling carbon is measured to be 0.165 percent, the phosphorus is measured to be 0.0115 percent, and the nitrogen content is measured to be 23ppm after the slag pouring is finished.

Example 2

The invention discloses a converter reblowing steelmaking method with carbon and phosphorus protection, which comprises the following steps:

1. after the end point converting is finished, lifting the oxygen lance to a waiting position, and measuring the oxygen content of the molten steel to be 206ppm, the sampling carbon to be 0.162 percent, the phosphorus to be 0.0192 percent and the nitrogen content to be 25 ppm;

2. adding auxiliary raw materials: adding 3.5kg/t steel of lime and 4.2kg/t steel of sintered return ores into the converter;

3. high lance position supplement blowing: adjusting the lance position of the oxygen lance to 8500mm of the liquid level of the molten steel, opening oxygen, and controlling the oxygen supply intensity at 180m³The steel is/h.t steel, oxygen is cut off after oxygen supply for 33 s;

4. pouring out slag: and after the blowing is finished, the slag is poured for 3min, and after the slag pouring is finished, the oxygen content of molten steel is measured to be 223ppm, the sampling carbon is measured to be 0.154%, the phosphorus is measured to be 0.0129%, and the nitrogen content is measured to be 24 ppm.

Example 3

The invention discloses a converter reblowing steelmaking method with carbon and phosphorus protection, which comprises the following steps:

1. after the end point blowing is finished, the oxygen lance is lifted to a waiting position, and the oxygen content of the molten steel is measured to be 196ppm, the sampling carbon is measured to be 0.133 percent, the phosphorus is measured to be 0.0257 percent, and the nitrogen content is measured to be 22 ppm.

2. Adding auxiliary raw materials: adding lime 4.0kg/t steel and sintered return mine 8.1kg/t steel into the converter.

3. High lance position supplement blowing: adjusting the lance position of the oxygen lance to 7800mm of the liquid level of the molten steel, opening oxygen, and controlling the oxygen supply intensity at 210m³The steel is/h.t steel, and oxygen is cut off after the oxygen is supplied for 34 s.

4. Pouring out slag: and after the blowing-up is finished, the slag is poured for 4min, and the oxygen content of molten steel is measured to be 248ppm, the sampling carbon is measured to be 0.095 percent, the phosphorus is measured to be 0.0115 percent, and the nitrogen content is measured to be 22ppm after the slag pouring is finished.

The technical solution of the present invention is not limited; although some details are described, the device can be modified or parts can be modified and replaced; and such substitutions should not theoretically depart from the spirit and scope of the present invention.