An on-line ladle nozzle purging and sand pot method

Abstract

The application discloses an online ladle nozzle purging and ladle sanding method, which adopts an online operation mode to perform the ladle nozzle purging. When the ladle is in an online vertical position, twice purging and twice ladle sanding are combined to ensure that liquid slag in the ladle cannot be mixed into the drainage sand to cause an excessively thick sintering layer, thereby avoiding the problem of non-self-flow caused by the fact that the static pressure of molten steel cannot break through the sintering layer due to the excessively thick sintering layer, and improving the self-flow rate of the ladle.

Description

Technical Field

[0001] This invention relates to an online purging process for steel ladles and a method for sand preparation. Background Technology

[0002] As a special steel enterprise, our bearing steel is widely used in machinery manufacturing, railway transportation, automobile manufacturing, and defense industries. Our automotive steel, used for gears and crankshafts, is widely used by high-end automobile manufacturers both domestically and internationally. To ensure the safe and normal operation of equipment in the machinery, railway, and automotive industries, the steel used must have a high fatigue life. Therefore, the requirements for inclusions in the steel are extremely stringent. The ladle self-flow rate, as a crucial factor, is receiving increasing attention from special steel enterprises. In traditional methods, the ladle is purged while lying flat offline. When the ladle is vertical, due to the high temperature of the molten steel, liquid slag accumulates around the nozzle. The hot slag recirculation and mixing with the guiding sand results in an excessively thick sintered layer, which prevents the static pressure of the molten steel from breaking through the sintered layer when the slide gate opens, leading to a lack of self-flow. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention optimizes the two most important operations of ladle self-flow rate based on the factors affecting the ladle self-flow rate, thereby improving the ladle self-flow rate, meeting the production requirements of high-grade steel, and reducing the loss due to non-self-flow reversal.

[0004] The specific technical solution adopted in this invention is as follows:

[0005] An online ladle nozzle purging and sand-removing method, characterized by comprising the following steps:

[0006] 1) Before tapping, open the ladle to the sand position. With the ladle in a vertical position, use a hose with argon gas to purge the top water inlet of the ladle for 20-30 seconds to clean the liquid slag around the top water inlet.

[0007] 2) After purging, the ladle nozzles will be fully filled with sand.

[0008] 3) Use a flexible tube filled with argon gas to purge again for 20-30 seconds along the outward direction from the edge of the ladle's water inlet to keep the liquid slag away from the water inlet;

[0009] 4) After purging, sand is added again to make the upper surface of the water inlet protrude in a bun shape;

[0010] 5) Transfer the ladle to the tapping position.

[0011] Preferably, in steps 1) and 3), the purging argon flow rate is 20-30 L / min.

[0012] Preferably, in step 3), the outward extension range of the edge of the ladle water inlet is 8-10cm.

[0013] Preferably, 10 kg of sand is used per batch.

[0014] The beneficial effects of this invention are:

[0015] The method of this invention employs online operation for purging the ladle nozzle. When the ladle is in an online vertical position, a combination of two purging processes and two sand-filling processes is used. The first purging ensures that the molten slag around the upper nozzle of the ladle is cleaned up. The first sand-filling process fills the ladle nozzle. The second purging process moves the molten slag away from the upper nozzle. After the second sand-filling process, the upper surface of the upper nozzle protrudes in a bun shape, preventing the molten slag from flowing back. This ensures that the molten slag does not mix into the guiding sand, resulting in an excessively thick sintered layer. This avoids the problem of non-self-flow caused by the molten steel's static pressure being unable to break through the sintered layer when the slide plate is opened due to an excessively thick sintered layer. Detailed Implementation Example 1

[0016] This embodiment provides an online ladle nozzle purging and sand-removing method, which is applied to steel smelting using an electric arc furnace + LF + VD + CCM process, and includes the following steps:

[0017] 1) Before tapping, open the ladle to the sand position. With the ladle in a vertical position, use a hose with argon gas to purge the top water inlet of the ladle for 20-30 seconds to clean the liquid slag around the top water inlet.

[0018] 2) After purging, the ladle nozzles will be fully filled with sand.

[0019] 3) Use a flexible tube filled with argon gas to purge again for 20-30 seconds along the outward direction from the edge of the ladle's water inlet to keep the liquid slag away from the water inlet;

[0020] 4) After purging, sand is added again to make the upper surface of the water inlet protrude in a bun shape;

[0021] 5) Transfer the ladle to the tapping position.

[0022] In steps 1) and 3) above, the purging argon flow rate is 20-30 L / min. If the argon flow rate is too low, the liquid slag in the ladle cannot be cleaned properly; if the pressure and flow rate are too high, it will cause the molten steel to splash.

[0023] In step 3) above, the outward extension range of the ladle water inlet edge is 8-10cm, which can both ensure that the liquid slag in the outer area of ​​the water inlet is cleaned up and ensure that the cleaning area is not too large, thus avoiding a significant increase in cleaning time.

[0024] In steps 2) and 4) above, based on the inner diameter of the water inlet of 55mm, the total amount of sand to be poured is 20kg, and the amount of sand to be poured each time is 10kg. The first sand pouring makes the inlet full, and the second sand pouring makes the sand covering and guiding the upper part of the water inlet in a bun shape.

[0025] Compared with the existing method of purging the ladle while it is lying flat offline, the online ladle nozzle purging and sand-filling method of the present invention can ensure that the liquid slag in the ladle will not mix into the guide sand, increase the ladle self-flow rate by more than 2%, and provide a guarantee for the production of high-grade steel.

Claims

1. An on-line ladle nozzle purging and sanding method, characterized by, It comprises the following steps: 1) Before tapping, open the ladle to the sand filling position, and blow the upper nozzle of the ladle with an argon pipe for 20-30s in the vertical state, so as to clean the liquid slag around the upper nozzle of the ladle; 2) After the blowing, the sand filling makes the upper nozzle of the ladle full; 3) Again blow along the outward extending direction of the edge of the upper nozzle of the ladle with an argon pipe for 20-30s, so as to make the liquid slag of the ladle far away from the upper nozzle; 4) After the blowing, again sand filling makes the upper surface of the upper nozzle in the shape of a steamed bun; 5) Transport the ladle to the tapping position; In the steps 1) and 3), the flow of the blowing argon is 20-30L / min; In the step 3), the outward extending range of the edge of the upper nozzle of the ladle is 8-10cm; Each time, sand filling is 10kg.