CN102443679B - Production method of steel with ultralow oxide inclusions - Google Patents

Abstract

The invention discloses a production method of steel with ultralow oxide inclusions, which adopts a twice vacuum treatment process, wherein the first vacuum treatment utilizes carbon to deoxidize so as to reduce the content of free oxygen in the steel; the second vacuum treatment makes the inclusion float sufficiently to facilitate the removal of free oxygen. And an LF furnace is added between two vacuum treatment processes for treatment, so that the heating effect of the molten steel is ensured, the oxygen content in the steel is further removed by adding aluminum, and slag which is easy to adsorb impurities is formed. Meanwhile, in the later stage of the second vacuum treatment, a weak argon blowing process is adopted to further promote floating and removal of inclusions. By implementing the invention, the oxygen content in the steel can be stably controlled below 5ppm, and the average continuous casting of more than 3 cans in a single casting time can be realized.

Description

A kind of production method of ultra-low oxidation inclusion steel

technical field

The invention belongs to the technical field of steelmaking technology, and in particular relates to a production control method of ultra-low oxidation inclusion steel grades.

Background technique

With the development of iron and steel smelting technology, the requirements for the cleanliness of molten steel are getting higher and higher, especially the development of high-grade steel such as high-grade bearing steel, high-grade cutting wire, high-grade cord steel and liquefied gas oil storage tank, etc. Inclusions put forward higher specific requirements, and the requirements are getting higher and higher. The key indicator to measure the amount of oxidized inclusions is the content of [Or] in steel. At present, the inspection of finished products of some steel grades requires the content of [Or] in the steel to be less than 10ppm, that is, the so-called ultra-low oxidation inclusion steel, and even some extremely special steel grades require [Or] to be less than 5ppm. How to stably control [Or] in steel below 5ppm and meet the conditions for mass production has become an important issue to be solved urgently.

Contents of the invention

The purpose of the present invention is to solve the above problems, thereby providing a production method of ultra-low oxidation inclusion steel which can control [Or] in steel below 5ppm and realize continuous pouring of more than 3 cans in a single pouring time.

For reaching this purpose, the present invention has taken following technical solution:

A method for producing ultra-low oxidation inclusion steel, which adopts two vacuum treatment processes, and adds an LF furnace treatment process between the two vacuum treatment processes, and performs weak argon blowing operation after the vacuum treatment is completed; the specific method is:

First vacuum treatment requirements:

(1) Non-deoxidation and boiling tapping are used for tapping the converter, and the carbon weight percentage of the tapping of the converter is controlled at 0.08-0.12%;

(2) After moving into the vacuum equipment, add carburizer at a rate of 1kg per ton of steel to increase the reaction speed of C—O;

(3) The vacuum treatment time is controlled at 13-18min, and the argon blowing flow rate is 400-500Nl/min. After the molten steel level is stable, the vacuum is broken and moved to the LF furnace for treatment;

(4) The entire vacuum treatment time after moving into the vacuum equipment is controlled within 35-45 minutes;

LF Furnace Treatment:

(1) During the heating treatment in LF furnace, no large argon gas stirring is carried out, and the desulfurization and composition adjustment are all carried out under high vacuum conditions;

(2) The basicity of the LF furnace slag is controlled at 2.8-3.2, and the temperature is moved into the vacuum treatment area after the temperature reaches the vacuum requirement;

(3) The processing time of the whole LF furnace is controlled within 60-80 minutes;

Requirements for the second vacuum treatment:

(1) The vacuum treatment time is controlled at 15 minutes;

(2) During the vacuum treatment stage, the argon blowing flow rate of the ladle is controlled at 500Nl/min;

(3) The time at this stage is controlled within 35-45 minutes;

After the vacuum treatment, carry out weak argon blowing on the vacuum equipment:

(1) The flow rate of weak argon blowing is controlled at 100-300Nl/min;

(2) The time of weak argon blowing is controlled at 14-16min.

The positive effect of the present invention is:

Because the present invention aims at the technical problem to be solved, two vacuum treatment processes are adopted, and the first vacuum treatment utilizes carbon deoxidation, which can effectively reduce the content of free oxygen in the steel. The second vacuum treatment can fully float the inclusions, which is conducive to the removal of free oxygen.

Since the LF furnace treatment process is added between the two vacuum treatment processes, the temperature rise effect of the molten steel can be guaranteed, and the oxygen content in the steel can be further removed by adding aluminum to form a slag that is easy to absorb inclusions. At the same time, in the later stage of the second vacuum treatment, the weak argon blowing process can further promote the floating and removal of inclusions.

Tested in production practice, the implementation of the present invention can stably control the oxygen content in the steel below 5ppm, and realize the average continuous pouring of more than 3 cans in a single pouring time.

detailed description

100-ton converter, 100-ton LF furnace, and 100-ton vacuum treatment equipment are used to produce GCr15 steel.

Example 1:

The first vacuum treatment process:

1. Non-deoxidation and boiling tapping are adopted for converter tapping, and the carbon weight percentage of converter tapping is controlled at 0.09%.

2. After moving into the vacuum equipment, add 100kg recarburizer to increase the reaction speed of C—O.

3. The vacuum treatment time is controlled at 15 minutes, and the argon blowing flow rate is 400Nl/min. After the molten steel level is stable, the vacuum is broken and moved to the LF furnace for treatment.

4. The entire vacuum treatment time is controlled at 43 minutes.

LF furnace treatment process:

1. During the heating treatment of LF furnace, there is no argon gas stirring, and the desulfurization and composition adjustment are all carried out under high vacuum conditions.

2. The basicity of LF furnace slag is controlled at 2.9. After the temperature reaches the requirement of vacuum, it will be moved into the vacuum treatment area.

3. The time of this stage is controlled at 65 minutes.

The second vacuum treatment process:

1. The vacuum treatment time is controlled at 15 minutes.

2. During the vacuum treatment stage, the argon blowing flow rate of the ladle is controlled at 500Nl/min.

3. The time of this stage is controlled within 40 minutes;

After the vacuum treatment, carry out weak argon blowing on the vacuum equipment:

The flow rate of weak argon blowing is controlled at 160Nl/min; the time of weak argon blowing is controlled at 16min.

Example 2:

The first vacuum treatment process:

1. Converter tapping without deoxidation, boiling tapping, the weight percentage of carbon in converter tapping is controlled at 0.11%.

2. After moving into the vacuum equipment, add 100kg recarburizer.

3. The vacuum treatment time is controlled at 17 minutes, and the argon blowing flow rate is 480Nl/min. After the liquid steel level is stable, the vacuum is broken and moved to the LF furnace for treatment.

4. The entire vacuum treatment time is controlled at 36 minutes.

LF furnace treatment process:

1. During the heating treatment of LF furnace, there is no argon gas stirring, and the desulfurization and composition adjustment are all carried out under high vacuum conditions.

2. The basicity of LF furnace slag is controlled at 3.1. After the temperature reaches the requirement of vacuum, it will be moved into the vacuum treatment area.

3. The time of this stage is controlled at 80 minutes.

The second vacuum treatment process:

1. The vacuum treatment time is controlled at 15 minutes.

2. During the vacuum treatment stage, the argon blowing flow rate of the ladle is controlled at 500Nl/min.

3. The time of this stage is controlled at 37 minutes.

After the vacuum treatment, carry out weak argon blowing on the vacuum equipment:

The flow rate of weak argon blowing is controlled at 280Nl/min; the time of weak argon blowing is controlled at 14min.

Claims (1)

1. a production method for ultralow oxide inclusion steel, is characterized in that, takes twice vacuum processing technique, and between twice vacuum processing technique, add LF stove treatment process, carries out soft argon blowing operation after vacuum-treat terminates; Its concrete grammar is:

First time vacuum-treat requires:

(1), converter tapping take not deoxidation, boiling tapping, converter tapping carbon weight percent controls at 0.08-0.12%;

(2), move into vacuum apparatus after, the ratio adding 1kg in steel per ton adds carburelant, improves C-O speed of response;

(3), vacuum processing time controls at 13-18min, and argon blowing rate is 400-500Nl/min, until molten steel face steadily after, broken empty, remove to LF stove and process;

(4) the whole vacuum-treat periodic Control after vacuum apparatus, is certainly moved at 35-45min;

The process of LF stove:

(1), do not carry out large argon gas stirring during LF stove heat treated, desulfurization and adjusting component carry out all in high vacuum conditions;

(2), LF stove basicity of slag controls at 2.8-3.2, and namely temperature reaches moves into vacuuming area after vacuum requirement;

(3), the whole LF stove treatment time controls at 60-80min;

Second time vacuum-treat requires:

(1), vacuum processing time controls at 15min;

(2), the ladle argon-blown flow control of vacuum-treat stage is at 500Nl/min;

(3), this phases-time controls at 35-45min;

After vacuum-treat terminates, vacuum apparatus carries out soft argon blowing:

(1), soft argon blowing flow control is at 100-300Nl/min;

(2), soft argon blowing time controling is at 14-16min.