Large freezing tank iron block decomposition method based on temperature control softening and saw cutting

Abstract

The invention discloses a large freezing tank iron block decomposition method based on temperature control softening and saw cutting, and relates to the technical field of metallurgical equipment maintenance. Comprising the following steps: pretreatment; heating and preserving heat; saw cutting; and post-processing. The method has the beneficial effects that high-temperature molten metal splashing and blasting risks are avoided, the operation process is controllable, and unconventional high-risk operation is avoided. And the frozen iron block is actively softened, so that the mechanical cutting resistance is greatly reduced, and the treatment period is shortened to be within 12 hours from 24-72 hours of a traditional method. Meanwhile, the overall investment is small, the operation cost is low, and the tool loss cost is reduced by 50% or above. And by adjusting the heating temperature and saw cutting parameters, the device can be suitable for treating frozen tank iron with different sizes and components.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgical equipment maintenance, and particularly relates to a large frozen ladle iron block decomposition method based on temperature control softening and sawing. BACKGROUND

[0002] In steel smelting production, the molten iron ladle is caused to solidify due to temperature out of control or equipment failure, forming a "frozen ladle" accident, which is an important problem affecting continuous production and equipment safety. At present, the traditional method for processing frozen ladle iron in the industry mainly has the following disadvantages: Oxygen cutting method: easy to cause fire and explosion during operation, high safety risk, and poor cutting surface quality, and large subsequent processing workload.

[0003] Blasting method: great safety hazard, serious threat to surrounding equipment and environment, and limited application range due to site and frozen iron structure.

[0004] In the prior art, although there is a solution of contacting hot molten steel with the surface of the frozen ladle (such as published patent CN120023325A), which improves the processing method to some extent, but this method still has problems of low thermal efficiency, high energy consumption, and long processing period. Especially for large frozen ladle iron blocks with a volume of more than 5 cubic meters, the above methods are difficult to achieve safe, fast and efficient decomposition.

[0005] The root cause is that the existing technology does not systematically utilize the internal relationship between the hardness and temperature of iron metal. Cast iron has high hardness (HB200-300) at room temperature and is difficult to cut, but as the temperature rises, its hardness decreases significantly, and at 400-600 DEG C, the hardness can be reduced to HB120-180, and the processability of the material is fundamentally improved. Therefore, developing a new method based on this principle that can actively control material properties and achieve safe and efficient processing has become an urgent need in the industry. SUMMARY

[0006] The present application aims to overcome the deficiencies and shortcomings in the prior art, and provides a large frozen ladle iron block decomposition method based on temperature control softening and sawing. The present application avoids the risk of high-temperature molten metal splashing and blasting, and the operation process is controllable without non-routine high-risk operations. By actively softening the frozen iron block, the mechanical cutting resistance is greatly reduced, and the processing period is shortened from 24-72 hours of the traditional method to 12 hours or less. At the same time, the overall investment is small, the operation cost is low, and the tool wear cost is reduced by more than 50%. By adjusting the heating temperature and sawing parameters, the frozen ladle iron of different sizes and compositions can be processed.

[0007] In order to achieve the above object, the present application adopts the following technical solution: A large frozen tank iron block decomposition method based on temperature control softening and sawing, comprising the following steps: pretreatment: cleaning the surface of the frozen tank iron block and determining the cutting path; heating and keeping warm: heating the pretreated frozen tank iron block to a target temperature of 400-600 DEG C and keeping warm, so that the internal and external temperatures of the frozen tank iron block are uniform and the hardness is reduced; sawing: under the condition of keeping warm, using sawing equipment to mechanically cut and decompose the softened frozen tank iron block; post-processing: recycling the cut iron block.

[0008] Further, in the pretreatment, a guide groove with a machining depth of 2-3 mm is processed on the determined cutting path.

[0009] Further, in the heating and keeping warm, the heating method adopts a stepwise heating method, specifically: first stage: heating from room temperature to 200 DEG C at a rate of not more than 10 DEG C / 15 min and keeping warm for 20-40 min; second stage: heating from 200 DEG C to 400 DEG C at a rate of not more than 10 DEG C / 12 min and keeping warm for 0.5-1.5 h; third stage: heating from 400 DEG C to the target temperature at a rate of not more than 10 DEG C / 10 min and keeping warm for 1-3 h.

[0010] Further, in the heating and keeping warm, the target temperature is 400 DEG C to 600 DEG C, and is determined as the optimal sawing temperature according to the volume of the frozen iron.

[0011] Further, in the sawing, the type of saw blade is selected according to the composition of the frozen tank iron block: for ordinary cast iron, high-speed steel saw blade is selected, the saw blade tooth pitch is 1.5-2.0 mm, and the sawing speed is 30-40 times per minute; for high-carbon cast iron, hard alloy saw blade is selected, the saw blade tooth pitch is 1.0-1.5 mm, and the sawing speed is 20-30 times per minute; for alloy cast iron, hard alloy saw blade is selected, the saw blade tooth pitch is 0.8-1.2 mm, and the sawing speed is 20-25 times per minute.

[0012] Further, in the sawing, an atomizing spray cooling system is used to cool the sawing part, the saw blade temperature is controlled below 150 DEG C, and the water-gas mixing ratio of the atomizing cooling system is 1:8.

[0013] After adopting the above technical solution, the present application has the following significant beneficial effects compared with the prior art: 1. High safety: avoids the risk of high-temperature molten metal splashing and blasting, and the operation process is controllable without non-conventional high-risk operation.

[0014] 2. Efficiency is significantly improved: by actively softening the frozen iron block, the mechanical cutting resistance is greatly reduced, and the processing period is shortened to 12 hours or less from 24-72 hours of the traditional method.

[0015] 3. Economical: Low equipment investment, low operating cost, tool wear cost reduced by more than 50%.

[0016] 4. Strong adaptability: By adjusting the heating temperature and sawing parameters, it can be applied to different sizes and components of frozen tank iron processing. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 is a method flowchart of the present application.

[0019] Figure 2 is an iron metal temperature and hardness relationship curve used in the present application. DETAILED DESCRIPTION

[0020] Referring to Figures 1-2 The technical solutions adopted in the present embodiment are as follows: EMBODIMENT

[0021] A 320-ton molten iron tank of a certain steel plant had a frozen tank accident, forming a huge frozen tank iron block of about 8 cubic meters, with a high-carbon cast iron composition.

[0022] Treatment process: Pretreatment: Remove the slag and oxides on the surface of the frozen tank iron block. According to the shape and internal stress analysis, determine the optimal cutting path. Use an angle grinder to process a guide groove with a depth of about 2.5mm on the cutting line.

[0023] Heating and insulation: Put the frozen tank iron block into the trolley type controllable atmosphere heating furnace.

[0024] Ladder heating method is adopted: first stage: from room temperature to 200℃ at a rate of 10℃ / 15min, and keep warm for 30min; second stage: from 200℃ to 450℃ at a rate of 10℃ / 12min, and keep warm for 2 hours, to ensure uniform internal and external temperature. Use an infrared temperature detector for real-time monitoring, and control the temperature deviation within ±5℃.

[0025] Sawing: According to its high-carbon composition, a carbide saw blade is selected, with a pitch of 1.5mm.

[0026] The sawing frequency is set to 25 times / min. Start the atomizing cooling system (water-gas mixture ratio controlled at 1:8) to continuously cool the sawing part, ensuring that the saw blade temperature is below 120℃.

[0027] Post-processing: The cut iron block is weighed and recorded, and transported to the steelmaking workshop for reuse.

[0028] Effect: The total processing time is about 10 hours, the flatness error of the cutting surface is less than 1mm, and the sawing deviation is less than ±0.25mm. There is no safety accident in the whole processing process, and the equipment returns to normal operation. Compared with traditional flame cutting, the efficiency is improved by more than 60%, and the tool wear is reduced by 50%.

[0029] Example 2: Treatment of medium-sized frozen tank iron The frozen tank of the 100-ton molten iron tank of the foundry is about 3 cubic meters in volume, and the composition is ordinary cast iron.

[0030] Treatment process: Pretreatment: After cleaning the surface, determine the cutting path, and process the guide groove.

[0031] Heating and holding: Due to the small volume, an induction heating device is used to improve efficiency. Heat to 400℃, and hold for 1.5 hours.

[0032] Sawing: According to its ordinary cast iron composition, high-speed steel saw blade is selected, with a pitch of 2.0mm. The sawing frequency is set to 35 times / minute. The atomizing cooling system is started to control the saw blade temperature.

[0033] Post-processing: The cut iron block is recycled and used.

[0034] Effect: The total processing time is only 7 hours. The cutting efficiency is improved by 50% compared with traditional mechanical cold cutting, and the saw blade wear is reduced by 30%. It is proved that the invention is also efficient and economical for small and medium-sized frozen tank iron. Example

[0035] To verify the universality and superiority of the method of the invention, different volumes of frozen tank iron are treated, and the key effect data are as follows: Freezer body Heating temperature Treatment time Cutting quality Equipment recovery time Volume (m3) (℃) (Hours) Evaluation (Hours) 3-5 400-450 6-8 Excellent 8-10 5-8 450-520 8-12 Good 10-14 >8 520-600 12-16 Passable 14-18 Conclusion: The above examples fully show that the frozen tank iron treatment method provided by the invention based on temperature control softening and mechanical cutting can safely, efficiently and at low cost process frozen tank iron of different sizes and compositions by systematically controlling the heating process and sawing parameters, and has high industrial application value.

[0036] The above is only to illustrate the technical solutions of the invention, not to limit it. Other modifications or equivalent replacements of the technical solutions of the invention made by those skilled in the art should be covered within the scope of the claims of the invention, as long as they do not deviate from the spirit and scope of the technical solutions of the invention.

Claims

1. A method for decomposing large frozen can iron blocks based on temperature-controlled softening and sawing, characterized in that, Includes the following steps: S1, Pre-treatment: Clean the surface of the frozen can iron block and determine the cutting path; S2, Heating and Insulation: The pre-treated frozen iron block is heated to the target temperature of 400℃-600℃ and then kept warm to make the temperature inside and outside the frozen iron block uniform and reduce its hardness. S3, Sawing: Under heat preservation conditions, use sawing equipment to mechanically cut and decompose the softened frozen can iron block; S4, Post-processing: Recycling the cut iron blocks.

2. The method for decomposing large frozen can iron blocks based on temperature-controlled softening and sawing according to claim 1, characterized in that: In step S1, a guide groove with a depth of 2-3 mm is machined on the determined cutting path.

3. The method for decomposing large frozen can iron blocks based on temperature-controlled softening and sawing according to claim 1, characterized in that: The heating method in step S2 adopts a stepped heating method, specifically as follows: First stage: Increase the temperature from room temperature to 200℃ at a rate of no more than 10℃ / 15 minutes, and hold at that temperature for 20-40 minutes; Second stage: Increase the temperature from 200℃ to 400℃ at a rate of no more than 10℃ / 12 minutes, and hold at that temperature for 0.5-1.5 hours; The third stage: Increase the temperature from 400℃ to the target temperature at a rate of no more than 10℃ / 10 minutes, and hold for 1-3 hours.

4. The method for decomposing large frozen can iron blocks based on temperature-controlled softening and sawing according to claim 1, characterized in that: The target temperature in step S2 is 400℃ to 600℃, and the optimal sawing temperature is determined based on the size of the frozen iron.

5. The method for decomposing large frozen can iron blocks based on temperature-controlled softening and sawing according to claim 1, characterized in that: In step S3, the saw blade type is selected based on the composition of the frozen iron block: For ordinary cast iron, high-speed steel saw blades are selected, with a saw blade tooth pitch of 1.5-2.0mm and a sawing speed of 30-40 cuts per minute; For high-carbon cast iron, use carbide saw blades with a tooth pitch of 1.0-1.5mm and a sawing speed of 20-30 cuts per minute. For alloy cast iron, use carbide saw blades with a tooth pitch of 0.8-1.2mm and a sawing speed of 20-25 cuts per minute.

6. The method for decomposing large frozen can iron blocks based on temperature-controlled softening and sawing according to claim 1, characterized in that: In step S3, an atomized spray cooling system is used to cool the sawing part, controlling the saw blade temperature below 150°C, and the water-air mixing ratio of the atomized cooling system is 1:

8.

7. The application of the method for handling frozen molten iron in a ladle as described in any one of claims 1-6 in the handling of molten iron ladle freezing accidents in iron and steel metallurgical enterprises.

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