A method for using a walking beam furnace to accommodate billets with large-span size variations

Abstract

This invention discloses a method for using a walking beam furnace to accommodate billets with large-span variations in specifications. The method includes the following steps: billets inside the furnace are advanced to the discharge position in steps L1, maintaining a constant discharge rhythm; billets outside the furnace are loaded at intervals L1 and L2, the least common multiple of L; after all billets inside the furnace have been discharged, billets are then loaded and discharged normally again at intervals L2. This invention, without adding extra equipment, can achieve mixed loading of billets with different specifications and different intervals within the furnace at a relatively low cost, enabling seamless switching in the production process, improving the overall production line efficiency and the furnace's utilization efficiency, thereby achieving energy conservation and emission reduction.

Description

Technical Field

[0001] This invention discloses a method for using a walking beam furnace to accommodate billets with large-span size variations. Background Technology

[0002] Nowadays, most metal processing furnaces used in large-scale production are walking beam furnaces, especially in large metal rolling production lines where they account for the vast majority. Typically, the billet specifications (cross-sections) of a production line are only one type or do not vary much. When moving the billets within the furnace, the same step distance can be used to ensure that the billets are distributed throughout the furnace at reasonable intervals, thus maximizing the furnace's efficiency.

[0003] With increasingly demanding market requirements, especially as specialty metal manufacturers' orders become more specialized, diversified, and fragmented, they need to use the same production line to produce a wider range of product specifications to meet the needs of different customers. Under current technological conditions, there are generally two approaches when the specifications of the billet vary significantly:

[0004] 1) With the pitch unchanged, when changing from a large billet to a small billet, it still takes one step to load one billet; when changing from a small billet to a large billet, it takes two steps (or more) to load one billet. This increases the billet spacing and reduces the furnace's efficiency. For example, when using a 450mm pitch to produce billets with a 300mm pitch, the furnace efficiency is... When producing billets with a 450mm pitch using a 2×300mm pitch, the furnace utilization efficiency is: It is evident that the efficiency is very low, the economic benefits are extremely poor, and it also affects product quality.

[0005] 2) Emptying the existing billets in the furnace before loading new billets inevitably creates a waiting period for materials, severely disrupting the production rhythm and causing reduced output and energy waste. Taking a 160t / h special steel heating furnace as an example, the furnace is about 35m long. After emptying the furnace and loading it with new materials, it takes more than 3 hours to tap the steel. This results in a direct production stoppage of at least 3 hours, reducing output by 480t. Assuming a profit of 250 yuan per ton of steel, the loss reaches 120,000 yuan, and the energy consumption loss is about 130GJ. Even without considering personnel and equipment costs, the losses are still huge if the specifications change frequently.

[0006] In conclusion, to adapt to the trend of specialization, diversification, and fragmentation in production orders, it is necessary to find a method that can meet this demand, eliminate or reduce the resulting losses, and achieve the goals of energy conservation, emission reduction, and green economic development. Summary of the Invention

[0007] To overcome the above-mentioned defects, the present invention provides a control method for seamless online switching of a walking beam furnace when producing billets of different specifications, which does not require long-term inefficient operation or emptying the furnace to stop production and wait for materials.

[0008] To achieve the above objectives, the present invention provides a method for using a walking beam furnace to accommodate billets with large-span size variations, comprising the following steps:

[0009] The billet inside the furnace is advanced to the discharge position in steps L1, and the discharge rhythm remains unchanged.

[0010] The billets outside the furnace are loaded into the furnace at intervals L1 and L2, which is the least common multiple of L;

[0011] After all the billets in the furnace have been removed, the billets are then loaded and discharged normally at a step distance of L2.

[0012] Furthermore, the effective furnace length of the heating furnace is a common multiple of the step distance required for adding billets of different specifications.

[0013] Furthermore, the method includes the following specific steps:

[0014] (1) When billet a in the furnace needs to be switched to billet b, that is, when billet a is fully covered in the furnace and billet b is about to enter the furnace, billet a in the furnace still advances to the discharge position with a step distance L1, and the discharge rhythm remains unchanged.

[0015] (2) When the last billet a in the furnace is moved to the least common multiple L of the distance from the charging position L1 and L2, billet b is placed in the furnace and positioned at the charging position, and billet b begins to be charged into the furnace at intervals of L.

[0016] (3) During billet switching, the billet is always moved with L1 as the step distance to maintain the steel output rhythm.

[0017] (4) After all the billet a is taken out of the furnace, it is then loaded and discharged normally with a step distance of L2.

[0018] The method described in this invention requires no additional equipment and is simple to implement. First, this method eliminates the situation of an empty furnace waiting for material. There is almost no efficiency loss when switching from small-sized billets to large-sized billets (due to the slower production pace of large billets). Efficiency loss only occurs during the 2-3 hours of switching from large-sized to small-sized billets, greatly improving the economic efficiency of switching billet sizes. Simultaneously, the step distance remains constant during billet switching, with only a change in the charging rhythm. After the switch is complete, it resumes operation with another constant step distance. Therefore, the control algorithm is also very simple and has a high fault tolerance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the switching from a large billet to a small billet according to the present invention;

[0020] Figure 2 This is a schematic diagram illustrating the switching from small billet to large billet according to the present invention; Detailed Implementation

[0021] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The simplified embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the simplified embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0026] (1) The two different specifications of billets have a furnace transfer distance of L1 for the large billet a and L2 for the small billet b, where L1 > L2 and their least common multiple is L. The transfer distance L for billet a requires m1 steps, and the transfer distance L for billet b requires m2 steps, i.e., L = m1 × L1 = m2 × L2.

[0027] (2) When designing the heating furnace system, the step distance of billets of different specifications being moved in the walking beam heating furnace should be taken into account, and the effective furnace length S should be designed as a common multiple of the required different step distances, S=n×L.

[0028] Switching from large billet a to small billet b:

[0029] (3) When billet a in the furnace is to be switched to billet b (i.e. billet a is fully covered in the furnace and billet b is about to be put into the furnace), billet a in the furnace will still advance to the discharge position in steps L1, and the discharge rhythm will remain unchanged.

[0030] (4) When the last billet a in the furnace is moved to the least common multiple L of the distance from the charging position L1 and L2, the billet b is placed in the furnace and positioned at the charging position, and the billet b begins to be charged into the furnace at intervals of L.

[0031] (5) During the billet switching period, the billet is always moved with L1 as the step distance to keep the steel output rhythm unchanged.

[0032] (6) After all the billet a is taken out of the furnace, it is then loaded and discharged normally with a step distance of L2.

[0033] (7) Since the spacing between the billet b is the least common multiple of L1 and L2, the billet b can be perfectly moved to the discharge position with L1 as the step distance during the specification switching period, and can also be perfectly moved to the discharge position with L2 as the step distance after the switching is completed.

[0034] Small billet b is switched to large billet a:

[0035] (8) When billet b in the furnace is to be switched to billet a (i.e. billet b is filled with billet a in the furnace and is about to be put into the furnace), billet b in the furnace will still advance to the discharge position in steps of L2, and the discharge rhythm will remain unchanged.

[0036] (9) When the last billet b in the furnace is moved to the least common multiple L of the distance from the charging position L1 and L2, the billet a is positioned in the furnace and the billet a begins to be charged into the furnace at intervals of L.

[0037] (10) During the billet switching period, the billet is always moved with a step distance of L2 to maintain the steel output rhythm.

[0038] (11) After all the billet a is taken out of the furnace, it is then loaded and discharged normally with a step distance of L1.

[0039] (12) Since the spacing between billet a is the least common multiple of L1 and L2, billet a can be perfectly moved to the discharge position with L2 as the step distance during the specification switching period, and can also be perfectly moved to the discharge position with L1 as the step distance after the switching is completed.

[0040] The present invention has been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described above. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Many other changes and modifications made without departing from the concept and scope of the present invention should be considered within the scope of protection of the present invention.

[0041] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for using a walking beam furnace to accommodate billets with large-span size variations, characterized in that: The method includes the following steps: The billet inside the furnace is advanced to the discharge position in steps L1, and the discharge rhythm remains unchanged. The billets outside the furnace are loaded into the furnace at intervals L1 and L2, which is the least common multiple of L; After all the billets in the furnace have been removed, the billets are then loaded and discharged normally at a step distance of L2. The effective furnace length of the heating furnace is a common multiple of the step distance required for adding billets of different specifications; The method includes the following specific steps: (1) When billet a in the furnace needs to be switched to billet b, that is, when billet a is fully covered in the furnace and billet b is about to enter the furnace, billet a in the furnace still advances to the discharge position with a step distance L1, and the discharge rhythm remains unchanged. (2) When the last billet a in the furnace is moved to the least common multiple L of the distance from the charging position L1 and L2, billet b is placed in the furnace and positioned at the charging position, and billet b begins to be charged into the furnace at intervals of L. (3) During billet switching, the billet is always moved with L1 as the step distance to maintain the steel output rhythm. (4) After all the billet a is taken out of the furnace, it is then loaded and discharged normally with a step distance of L2.

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