阅读说明：本技术 提高连铸中间包余留钢回收率的方法 (Method for improving recovery rate of residual steel of continuous casting tundish ) 是由 茶维杰 和浩 杨冠龙 金勇� 沈蓉华 邱肖 金安林 樊昆祥 于 2021-06-29 设计创作，主要内容包括：本发明提供一种提高连铸中间包余留钢回收率的方法,其特征在于包括下列步骤：1)在中间包上设置减弱或阻止涡流形成的带钢水进、出口的挡渣坝,让钢水经进口先进入挡渣坝,再从出口流入中间包；2)当中间包的钢水量达到连铸浇钢时,开启中间包底部的注流口将钢水浇到下方的连铸机铸锭模中进行连铸；3)当钢水浇注完成后,控制中间包内的：渣层厚度在30mm以内、温度高于正常连铸温度10—15℃或者将连铸钢坯的拉坯速度较正常拉坯速度提高0.3—0.5m/min；4)当中间包钢水深度下降至300mm时,进行堵流。避免在中间包内产生涡流,保证钢锭质量,提高余留钢回收率,降低成本。(The invention provides a method for improving the recovery rate of residual steel of a continuous casting tundish, which is characterized by comprising the following steps: 1) arranging a slag dam for weakening or preventing the formation of vortex and provided with a strip steel water inlet and a strip steel water outlet on the tundish, so that molten steel firstly enters the slag dam through the inlet and then flows into the tundish from the outlet; 2) when the molten steel amount of the tundish reaches the continuous casting and steel casting, opening a pouring port at the bottom of the tundish to pour the molten steel into a continuous casting machine ingot mould below the tundish for continuous casting; 3) after the pouring of the molten steel is finished, controlling the following components in the tundish: the thickness of the slag layer is within 30mm, the temperature is 10-15 ℃ higher than the normal continuous casting temperature, or the blank drawing speed of the continuous casting billet is improved by 0.3-0.5 m/min compared with the normal blank drawing speed; 4) when the depth of the tundish steel water is reduced to 300mm, the flow is blocked. Avoid producing the vortex in the middle package, guarantee the steel ingot quality, improve the surplus steel rate of recovery, reduce cost.)

1. A method for improving the recovery rate of the residual steel of a continuous casting tundish is characterized by comprising the following steps:

(1) arranging a slag dam for weakening or preventing the formation of vortex and provided with a strip steel water inlet and a strip steel water outlet on the tundish, so that molten steel firstly enters the slag dam through the inlet and then flows into the tundish from the outlet;

(2) when the molten steel amount of the tundish reaches the continuous casting and steel casting, opening a pouring port at the bottom of the tundish to pour the molten steel into a continuous casting machine ingot mould below the tundish for continuous casting;

(3) after the pouring of the molten steel is finished, controlling the following components in the tundish: the thickness of the slag layer is within 30mm, the temperature is 10-15 ℃ higher than the normal continuous casting temperature, or the blank drawing speed of the continuous casting billet is improved by 0.3-0.5 m/min compared with the normal blank drawing speed;

(4) when the depth of the tundish steel water is reduced to 300mm, carrying out the following flow blocking operation;

(4.1) blocking the pouring gate in the middle of the bottom of the tundish, and continuously casting the rest pouring gates;

(4.2) when the depth of the tundish steel water is reduced to only 200mm, blocking secondary middle pouring gates on two sides of the middle pouring gate, and continuously pouring the pouring gates on two sides;

and (4.3) when the depth of the molten steel of the tundish is reduced to only 100mm, blocking the pouring gate on one side, continuously casting the molten steel of the tundish on the other side until the depth of the residual molten steel of the tundish is less than 50mm, and blocking the pouring gate on the other side.

2. The method according to claim 1, wherein the step (1) of providing a slag dam on the tundish is as follows: the middle rear side wall at the top of the tundish is provided with an outward and inward protruding groove, the groove is a slag blocking dam, the top of the groove is open, the bottom of the groove is closed, a steel nozzle is arranged on the wall of the inward protruding groove and at a position far away from the groove bottom 2/3, and the height of the groove top of the inward protruding groove is greater than that of the groove top of the outward protruding groove, so that molten steel enters the groove from an opening at the top of the groove and then flows out of the steel nozzle into the tundish, the purity of the molten steel is effectively improved, the movement track of the molten steel in the tundish is effectively improved, the formation of pouring vortex of the tundish is weakened or avoided, and meanwhile, steel slag floats upwards at the top of the groove and is blocked in the groove, and slag discharging is facilitated.

3. The method according to claim 1, wherein in the step (2), slag is discharged in time when the thickness of the tundish slag layer is larger than 30mm, and the thickness of the tundish slag layer is controlled within 30 mm.

4. The method according to claim 1, wherein the tundish temperature is controlled to be 10-15 ℃ higher than the normal continuous casting temperature in the step (3) in order to prevent the tundish temperature from decreasing too fast after the ladle casting is finished, so that a pouring gate at the bottom of the tundish is blocked, the amount of the residual molten steel in the tundish is increased, and the depth of the residual molten steel in the tundish is ensured to be less than 50 mm.

5. The method as claimed in claim 1, wherein the casting in the tundish in the step (3) is performed by increasing the withdrawal speed of the continuously cast steel slab by 0.3 to 0.5m/min from the normal withdrawal speed to ensure that the depth of the remaining molten steel in the tundish is less than 50 mm.

Technical Field

The invention relates to a method, in particular to a method for improving the recovery rate of residual steel of a continuous casting tundish, belonging to the technical field of steel smelting.

Background

The amount of steel remaining in the tundish is inevitable steel loss during the continuous casting production process, and is the molten steel that must remain in the tundish after the tundish is stopped casting. In the continuous casting production process, in order to avoid the problem that the liquid level of the tundish is too low, so that molten steel generates vortex in the area of a water gap of the tundish, thereby impurities and air are involved in the molten steel, and the quality defect of a billet after continuous casting is caused, a certain amount of molten steel must be kept in the tundish when the continuous casting stops casting, when the next molten steel ladle is poured into the tundish, the part of molten steel and the impurities in the molten steel sink the area of the water gap of the tundish, so that the part of impurities in the tundish cannot be involved in a casting flow, residual molten steel must be left in the tundish, and on the other hand, the problems that the loss of the residual molten steel in the tundish is large and the cost is increased in the continuous casting production process are caused. Therefore, the method reasonably controls the residual steel amount of the tundish, and plays an important role in improving the metal recovery rate, reducing the steel consumption and ensuring the quality of continuous casting products. At present, during continuous casting and stopping, the height of the residual molten steel in the tundish is controlled to be 200-300mm, the quality of the molten steel is 3-4 t, the amount of the residual molten steel is reduced along with the increase of the number of continuous casting and steel casting furnaces of the tundish and the reduction of the times of starting and stopping, but during stopping, the recovery rate of the residual molten steel in the tundish is not substantially improved, the amount of the residual molten steel used in the tundish per month is 63 per month, the loss of the residual molten steel in each tundish is 3-4 t, and the loss of the residual molten steel per month can reach 189 tons plus one ton, which is not beneficial to the development of steel-making, iron-saving and steel-increasing work and the improvement of related technical indexes. Therefore, there is a need for improvements in the prior art.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: how to reduce the amount of residual molten steel in the continuous casting of the tundish after the continuous casting and the stopping of the casting, improve the recovery rate of the residual steel in the tundish and reduce the loss of the steel.

The invention aims to provide a method for improving the recovery rate of the steel remained in the continuous casting tundish, so as to reduce the amount of the steel water remained in the continuous casting tundish and reduce the steel loss.

The invention is completed by the following technical scheme: a method for improving the recovery rate of the residual steel of a continuous casting tundish is characterized by comprising the following steps:

(1) arranging a slag dam for weakening or preventing the formation of vortex and provided with a strip steel water inlet and a strip steel water outlet on the tundish, so that molten steel firstly enters the slag dam through the inlet and then flows into the tundish from the outlet;

(2) when the molten steel amount of the tundish reaches the continuous casting and steel casting, opening a pouring port at the bottom of the tundish to pour the molten steel into a continuous casting machine ingot mould below the tundish for continuous casting;

(3) after the pouring of the molten steel is finished, controlling the following components in the tundish: the thickness of the slag layer is within 30mm, the temperature is 10-15 ℃ higher than the normal continuous casting temperature, or the blank drawing speed of the continuous casting billet is improved by 0.3-0.5 m/min compared with the normal blank drawing speed;

(4) when the depth of the tundish steel water is reduced to 300mm, carrying out the following flow blocking operation;

(4.1) blocking the pouring gate in the middle of the bottom of the tundish, and continuously casting the rest pouring gates;

(4.2) when the depth of the tundish steel water is reduced to only 200mm, blocking secondary middle pouring gates on two sides of the middle pouring gate, and continuously pouring the pouring gates on two sides;

and (4.3) when the depth of the molten steel of the tundish is reduced to only 100mm, blocking the pouring gate on one side, continuously casting the molten steel of the tundish on the other side until the depth of the residual molten steel of the tundish is less than 50mm, and blocking the pouring gate on the other side.

The step (1) of arranging the slag blocking dam on the tundish is as follows: the middle rear side wall at the top of the tundish is provided with an outward and inward protruding groove, the groove is a slag blocking dam, the top of the groove is open, the bottom of the groove is closed, a steel nozzle is arranged on the wall of the inward protruding groove and at a position far away from the groove bottom 2/3, and the height of the groove top of the inward protruding groove is greater than that of the groove top of the outward protruding groove, so that molten steel flows into the groove from an opening at the top of the groove and then flows into the tundish from the steel nozzle, thereby not only effectively improving the purity of the molten steel, but also effectively improving the motion track of the molten steel in the tundish, weakening or avoiding the formation of pouring vortex of the tundish, simultaneously enabling steel slag to float up to the top of the groove and be blocked in the groove, and being beneficial to slag discharge.

And (3) timely discharging slag when the thickness of the tundish slag layer in the step (2) is larger than 30mm, and controlling the thickness of the tundish slag layer within 30 mm.

The temperature of the tundish in the step (3) is controlled to be 10-15 ℃ higher than the normal continuous casting temperature, so that the problem that the temperature of the tundish is reduced too fast after the casting of the ladle to cause the blockage of a pouring gate at the bottom of the tundish, the amount of residual molten steel in the tundish is increased, and the depth of the residual molten steel in the tundish is ensured to be less than 50mm is solved.

And (4) when the tundish in the step (3) is used for casting, the blank drawing speed of the continuous casting billet is increased by 0.3-0.5 m/min compared with the normal blank drawing speed, and the depth of the residual molten steel in the tundish is ensured to be less than 50 mm.

The invention has the following advantages and effects: by adopting the technical scheme, the slag blocking dam is arranged, so that the vortex generated in the tundish is effectively avoided, the molten steel can not be wound with impurities and air into the cast ingot, the quality of the continuously cast steel ingot is ensured, the thickness, the temperature, the ingot pulling speed, the depth control of the residual molten steel and the effective flow blocking operation of the slag layer of the tundish after the continuous casting and the steel casting are finished are adopted, the residual molten steel amount is greatly reduced, the recovery rate of the residual steel is improved, 75 percent of the steel amount can be recycled after each pouring stop of each tundish, and the economic benefit is remarkable.

Drawings

FIG. 1 is a rear view of a tundish;

fig. 2 is a top view of fig. 1.

In the figure, 1 is a tundish, 2 is a pouring gate at the bottom of the tundish, 3 is a slag discharge gate at the rear side of the top of the tundish, 4 is a slag blocking dam, 41 is a groove wall protruding outwards from the slag blocking dam, 42 is a groove wall protruding inwards from the slag blocking dam, and 43 is a molten steel nozzle.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

The invention provides a method for improving the recovery rate of residual steel of a continuous casting tundish, which is characterized by comprising the following steps:

(1) arranging a slag dam for weakening or preventing the formation of vortex and provided with a strip steel water inlet and a strip steel water outlet on the tundish, so that molten steel firstly enters the slag dam through the inlet and then flows into the tundish from the outlet; wherein: the slag blocking dam is arranged on the tundish and comprises the following concrete components: the middle rear side wall of the top of the tundish 1 is provided with an outward and inward convex groove 4, the groove is a slag blocking dam, the top of the groove is open, the bottom of the groove is closed, a steel nozzle 43 is arranged on the groove wall 42 of the inward convex groove 4 and at a position far from the groove bottom 2/3, and the top height of the groove wall 42 of the inward convex groove 4 is greater than the top height of the groove wall 41 of the outward convex groove 4; molten steel enters the groove 41 from an opening at the top of the groove 4 and then flows out of a molten steel port 43 to enter the tundish 1;

(2) when the molten steel amount of the tundish 1 reaches the continuous casting and steel casting, opening a pouring port 2 at the bottom of the tundish to pour the molten steel into a continuous casting machine ingot mould below for continuous casting;

(3) after the pouring of the molten steel is finished, controlling the following components in the tundish 1: the thickness of a slag layer is within 30mm, and the temperature is 10 ℃ higher than the normal continuous casting temperature;

(4) when the depth of the molten steel in the tundish 1 is reduced to 300mm, carrying out the following flow blocking operation;

(4.1) blocking the pouring gate 23 at the middle of the bottom of the tundish 1, and continuously casting the rest pouring gates 21, 22, 24 and 25;

(4.2) when the depth of the molten steel in the tundish 1 is reduced to only 200mm, firstly blocking secondary middle pouring gates 22 and 24 at two sides of a middle pouring gate 23, and continuously pouring by using pouring gates at two sides 21 and 25;

(4.3) when the depth of the molten steel in the tundish 1 is reduced to only 100mm, the pouring gate 21 on the left side is blocked, the pouring gate 25 on the right side is continuously cast until the depth of the residual molten steel in the tundish is less than 50mm, and the pouring gate 25 on the right side is blocked.

Example 2

The invention provides a method for improving the recovery rate of residual steel of a continuous casting tundish, which is characterized by comprising the following steps:

(1) arranging a slag dam for weakening or preventing the formation of vortex and provided with a strip steel water inlet and a strip steel water outlet on the tundish, so that molten steel firstly enters the slag dam through the inlet and then flows into the tundish from the outlet; wherein: the slag blocking dam is arranged on the tundish and comprises the following concrete components: the middle rear side wall of the top of the tundish 1 is provided with an outward and inward convex groove 4, the groove is a slag blocking dam, the top of the groove is open, the bottom of the groove is closed, a steel nozzle 43 is arranged on the groove wall 42 of the inward convex groove 4 and at a position far from the groove bottom 2/3, and the top height of the groove wall 42 of the inward convex groove 4 is greater than the top height of the groove wall 41 of the outward convex groove 4; molten steel enters the groove 41 from an opening at the top of the groove 4 and then flows out of a molten steel port 43 to enter the tundish 1;

(2) when the molten steel amount of the tundish 1 reaches the continuous casting and steel casting, opening a pouring port 2 at the bottom of the tundish to pour the molten steel into a continuous casting machine ingot mould below for continuous casting;

(3) after the pouring of the molten steel is finished, controlling the following components in the tundish 1: the thickness of the slag layer is within 30mm, and the blank drawing speed of the continuous casting billet is improved by 0.3m/min compared with the normal blank drawing speed;

(4) when the depth of the molten steel in the tundish 1 is reduced to 300mm, carrying out the following flow blocking operation;

(4.1) blocking the pouring gate 23 at the middle of the bottom of the tundish 1, and continuously casting the rest pouring gates 21, 22, 24 and 25;

(4.2) when the depth of the molten steel in the tundish 1 is reduced to only 200mm, firstly blocking secondary middle pouring gates 22 and 24 at two sides of a middle pouring gate 23, and continuously pouring by using pouring gates at two sides 21 and 25;

(4.3) when the depth of the molten steel in the tundish 1 is reduced to only 100mm, the pouring gate 25 on the right side is blocked, the pouring gate 21 on the left side is continuously cast until the depth of the residual molten steel in the tundish is less than 50mm, and the pouring gate 21 on the left side is blocked.

In the embodiments 1 and 2 of the invention, the molten steel only remains 0.5t compared with the prior tundish continuous casting with the same yield when the casting is stopped for 1 time, and the molten steel remains 1.5 to 2.5t in the prior art; according to the calculation of using 63 tundishes per month at present, the molten steel is recycled 94-157 t per month; the processing cost of the steel per ton in the prior steelmaking is about 550 yuan/t, and the processing cost can be reduced by 5.2-8.6 ten thousand yuan per month after the molten steel recovery rate of a tundish is improved; the processing cost can be reduced by about 62.4-103.2 ten thousand yuan per year, and the economic benefit is obvious.