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CN-121988731-A - Method for improving self-opening rate of high alloy steel ladle

CN121988731ACN 121988731 ACN121988731 ACN 121988731ACN-121988731-A

Abstract

The invention discloses a method for improving the self-opening rate of a high alloy steel ladle, which comprises the following steps of measuring the temperature of an upper line ladle, pouring slag of a lower stage ladle, burning and cleaning a water gap, checking air brick test gas, filling sand into the ladle, confirming the quality of sand filling, adopting a '2+N' sand filling mode to ensure that the sand filling of the drainage sand is evenly filled, adopting a water gap baking and heat-preserving measure to reduce the moisture in a water gap channel to ensure the temperature around the water gap, ensuring that the drainage sand is kept in a loose and dry good state, confirming the sand filling quality twice after the sand filling is regulated, and reducing the probability of leakage of the drainage sand.

Inventors

  • Xue shun
  • WANG SHANG
  • XING DONGDONG
  • WANG FENG
  • GONG LEI
  • ZHOU KANG
  • XIONG LEI
  • CHENG YUAN

Assignees

  • 马鞍山钢铁有限公司

Dates

Publication Date
20260508
Application Date
20260313

Claims (10)

  1. 1. A method for improving the self-opening rate of a high alloy steel grade ladle, which is characterized by comprising the following steps: s1, measuring the temperature of an online ladle, namely baking the online ladle to ensure that the temperature of a lining refractory material at the bottom of the ladle is more than or equal to 700 ℃; s2, pouring slag from a lower ladle, namely pouring slag from the lower ladle after continuous casting and pouring, wherein the condition that no block slag falls down and liquid slag flows down is adopted; S3, performing nozzle burning cleaning, namely performing nozzle burning cleaning on the ladle after slag pouring, and then performing online baking, wherein when the upper nozzle needs to be replaced, the upper nozzle needs to be baked for 5-8 min by a coal oxygen gun after the upper nozzle is replaced; s4, air brick air test checking, namely after the burning cleaning is finished, air brick air test checking is carried out on the air brick in the steel ladle to ensure no air leakage; S5, pouring sand into the steel ladle, namely pouring the sand immediately after the on-line baking is finished, namely uniformly pouring 2 bags of chromium drainage sand into a water gap, and then pouring the rest 4-6 bags of chromium drainage sand into the water gap; and S6, confirming sand filling quality, namely opening the ladle to a tapping position for the second confirmation, and immediately opening the ladle to recharge sand or carrying out ladle replacement treatment if the situation of material shortage at the upper end of the diversion sand is found.
  2. 2. The method for improving the self-opening rate of the high alloy steel grade ladle according to claim 1, wherein in the step S2, the ladle is placed in a lower stage within 10min or less for deslagging, the deslagging ladle is inclined by 140-170 degrees, and deslagging time is 30-45S.
  3. 3. The method for improving the self-opening rate of the high alloy steel ladle according to claim 1, wherein in the step S3, a coal-oxygen lance is used for burning and washing residues around a water gap and a brick cup, the oxygen lance is used for blowing and sweeping the positions of the water gap channel, the brick cup bowl and the like, the pressure is 0.3-0.5 MPa, no residues exist in the water gap channel, and no broken residues and no thin residues exist at the brick cup.
  4. 4. The method for improving the self-opening rate of the high alloy steel grade ladle according to claim 1, wherein in the step S3, the online baking flow is 500-700 Nm 3 /h.
  5. 5. The method for improving the self-opening rate of the high alloy steel ladle according to claim 1, wherein in the step S4, a quick joint of a nitrogen pipeline is connected with an argon blowing port at the bottom of the ladle, an air valve is slowly opened, air is introduced, when the air pressure of the air brick is 0.4-0.8 MPa, the flow is 1000-1500 NL/min, the brick surface of the air brick at the bottom of the ladle is observed, the overall air flow of the brick surface is confirmed to be uniform, and no air leakage phenomenon exists.
  6. 6. The method for increasing the self-opening rate of a high alloy steel grade ladle according to claim 1, wherein in the step S5, chemical components and mass percentages of the chromium-based drainage sand are ：SiO 2 ：16~20%,Cr 2 O 3 ：36~39%,MgO：2~5%,Fe 2 O 3 ：20~23%,Al 2 O 3 ：10~13%,H 2 O≤0.5%,, and the balance is unavoidable impurities.
  7. 7. The method for improving the self-opening rate of the high alloy steel grade ladle as recited in claim 1, wherein the weight percentage of the chromium drainage sand with the granularity of 0.15-1.0 mm in the chromium drainage sand is more than or equal to 90%.
  8. 8. The method for improving the self-opening rate of the high alloy steel ladle according to claim 1, wherein in the step S6, the time from the end of sand filling to the beginning of tapping is less than or equal to 120min, the diversion sand is replaced again more than 120min, and a coal oxygen gun is required to bake a water gap before sand replacement for 5-8 min.
  9. 9. The method for improving the self-opening rate of the steel ladle of the high alloy steel grade according to claim 1, wherein the sum of the mass percentages of alloy elements in the steel ladle of the high alloy steel grade is more than or equal to 10%.
  10. 10. The method for improving the self-opening rate of the high alloy steel grade ladle according to claim 1, wherein the self-opening rate of the high alloy steel grade ladle is more than or equal to 99.3%.

Description

Method for improving self-opening rate of high alloy steel ladle Technical Field The invention belongs to the technical field of steel smelting, and particularly relates to a method for improving the self-opening rate of a high alloy steel ladle. Background Compared with common alloy steel, the high alloy steel with the total alloy element content of more than 10 percent, such as tube blank steel P92 and BZG, has the advantages that the steel slag is easy to adhere to the inner wall of a water gap and the surface of drainage sand due to the high alloy element content and the viscous molten steel. So as to slowly infiltrate into the gaps of sand grains to 'cement' the diversion sand. The long transfer time (from tapping to pouring end) of the high alloy steel molten steel is usually 5.5-7.5 hours, the longer the transfer time is, the longer the thermal action and penetration action time of molten steel and slag on the drainage sand are, and the risk of sintering is exponentially increased. And when a certain plant smelts high alloy steel, the average value of the steel ladle self-opening rate is 95.9 percent (95.3-96.7 percent) which is lower than the level of 99.8 percent of common alloy steel. The ladle self-opening rate (also called automatic pouring rate) is a core index of continuous casting production, and means that after a ladle opens a sliding gate, a drainage sand sintering layer can be broken through only by means of ferrostatic pressure, and the percentage of the total heat of the steel to realize natural pouring is calculated. The ladle self-opening rate directly relates to the core factors of high alloy steel quality, production safety, cost control and the like. The high alloy steel is extremely sensitive to the quantity and the type of internal inclusions, manual oxygen burning intervention is not needed for self-opening, secondary oxidation and slag rolling generated by oxygen burning seriously affect the purity of molten steel, degradation, furnace return and even scrapping of the high alloy steel are caused, the high alloy steel is a high added value steel type, and the self-opening failure often causes serious economic loss. And safety risks such as splashing, explosion and the like exist in manual oxygen burning. Disclosure of Invention In order to solve the technical problems, the invention provides a method for improving the self-opening rate of a high alloy steel ladle, which can improve the self-opening rate of the high alloy steel ladle to more than 99.3 percent. The technical scheme adopted by the invention is as follows: The invention provides a method for improving the self-opening rate of a high alloy steel ladle, which comprises the following steps: s1, measuring the temperature of an online ladle, namely baking the online ladle to ensure that the temperature of a lining refractory material at the bottom of the ladle is more than or equal to 700 ℃; s2, pouring slag from a lower ladle, namely pouring slag from the lower ladle after continuous casting and pouring, wherein the condition that no block slag falls down and liquid slag flows down is adopted; S3, performing nozzle burning cleaning, namely performing nozzle burning cleaning on the ladle after slag pouring, and then performing online baking, wherein when the upper nozzle needs to be replaced, the upper nozzle needs to be baked for 5-8 min by a coal oxygen gun after the upper nozzle is replaced; s4, air brick air test checking, namely after the burning cleaning is finished, air brick air test checking is carried out on the air brick in the steel ladle to ensure no air leakage; S5, pouring sand into the steel ladle, namely pouring the sand immediately after the on-line baking is finished, namely uniformly pouring 2 bags of chromium drainage sand into a water gap, and then pouring the rest 4-6 bags of chromium drainage sand into the water gap; and S6, confirming sand filling quality, namely opening the ladle to a tapping position for the second confirmation, and immediately opening the ladle to recharge sand or carrying out ladle replacement treatment if the situation of material shortage at the upper end of the diversion sand is found. In the step S2, pouring slag from a lower stage in the ladle which is less than or equal to 10min, tilting the slag pouring ladle by 140-170 degrees, and pouring slag for 30-45S. In the step S3, a coal-oxygen lance is used for burning and washing the water gap and residues around the brick cup, the oxygen lance is used for blowing and sweeping the positions of the water gap channel, the brick cup bowl opening and the like, the pressure is 0.3-0.5 MPa, no residues exist in the water gap channel, and no broken residues and no thin residues exist at the brick cup bowl opening. In the step S3, the online baking flow is 500-700 Nm 3/h. In the step S4, a quick joint of a nitrogen pipeline is connected with an argon blowing port at the bottom of a steel ladle, an air valve is slowly opened, air is