A method for Ф390 size quick-change tundish of round billet continuous casting

Abstract

The present application belongs to the field of casting technology, and particularly relates to a round billet continuous casting Φ390 specification quick-change tundish method. The technical scheme comprises the following steps: 1) connecting piece design; 2) quick-change tundish process parameter adjustment; 3) slagging; 4) quick-change process rhythm control; and 5) opening a closable small opening on each side of the mould cover, opening before tundish changing and closing after tundish changing. The present application has the advantages of short tundish changing time and firm connection of new and old casting billets.

Description

Technical Field

[0001] This invention belongs to the field of casting technology, and particularly relates to a method for quick tundish change in continuous casting of round billets with a specification of Ф390. Background Technology

[0002] The large round billet continuous casting machine at Taiyuan Iron & Steel Group's No. 1 Steelmaking Plant was completed and put into operation in March 2015. The Ф390 specification is the smallest and most in-demand specification, mainly used for producing wheel steel and alloy steel. Currently, the continuous casting machine operates on a single tundish system, requiring three hours between each casting cycle. This results in low efficiency, low capacity, high costs, low metal recovery, high scrap output, and low billet yield. Therefore, implementing quick tundish changeover is a key measure to increase the number of continuous casting heats and achieve continuous production. Summary of the Invention

[0003] To overcome the deficiencies in the aforementioned related technologies, this invention provides a method for quick tundish change in continuous casting of round billets with a specification of Ф390.

[0004] To achieve the above technical objectives, the present invention provides a method for quick-change tundish in continuous casting of round billets of specification Ф390, comprising:

[0005] 1) Connector design; The upper and lower cross sections of the connector are circular, the upper circle diameter of the connector is 330mm, the lower circle diameter of the connector is 227mm, the height of the connector is 500mm, the connector has an inverted conical structure, and 8 springs are welded to the outer ring of the connector;

[0006] 2) Adjustment of process parameters for quick tundish change process; The starting speed and initial pouring speed of the Ф390 specification round billet are 0.25m / min. After the tundish starts pouring, the water flow rate in each flow foot roller area increases by 100L / min compared to the previous water flow rate. After the length of the Ф390 specification round billet poured after the start of pouring is greater than 1000mm, the water flow rate is consistent with the previous flow rate.

[0007] 3) Slag removal; After the old tundish stops casting, a slag ring forms around the slag surface of the crystallizer. The slag ring is then removed.

[0008] 4) Quick ladle change process rhythm control: During the ladle change process, after the old tundish's tail furnace ladle has finished pouring the steel for the previous process, when the old tundish has 18-20t of steel remaining, the ladle change program is activated. When the remaining steel is 12t, the new tundish is checked. When the remaining steel is 6-8t, the old tundish stops pouring and moves the ladle, and the ladle change operation begins. Pouring begins when the new tundish has 25t of molten steel, ensuring the tundish liquid level is maintained at the start of pouring.

[0009] 5) Make a small, closable opening on each side of the crystallizer cover plate. Open it before changing the packing and close it after changing the packing.

[0010] The beneficial effects of this invention are as follows:

[0011] By adopting the quick-change tundish method with insert connectors, the tundish change process takes no more than 10 minutes, ensuring a firm connection between the old and new billets. Stable operation with quick-change tundishes has been achieved for the Ф390 specification of round billet continuous casting, and this technology has become a mature process. Continuous production has been enabled for the Ф390 specification, with a maximum of 87 consecutive heats, effectively improving the efficiency of the continuous casting machine and significantly increasing continuous casting capacity. Detailed Implementation

[0012] To make the above-mentioned objectives, features, and advantages of the present invention more apparent and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] To achieve the above technical objectives, the present invention provides a method for quick tundish change in continuous casting of round billets with a specification of Ф390, comprising:

[0014] 1) Connector design: The connector has a circular cross-section, with an upper diameter of 330mm, a lower diameter of 227mm, and a height of 500mm. It is inverted conical in shape, and 8 springs are welded to the outer ring to increase cooling intensity, shorten solidification time, and shorten the time for quick tundish replacement.

[0015] 2) Adjustment of process parameters during quick tundish change: For Ф390 specifications, the normal starting pouring speed is 0.30 m / min, and the initial pouring speed is 0.45 m / min. In order to ensure stable connection between the old and new billets after tundish change, both the starting pouring speed and the initial pouring speed are adjusted to 0.25 m / min. The pouring speed is adjusted again after there are no abnormalities at the connection point when exiting the crystallizer. Adjustment of water flow rate in the secondary cooling water foot roller area: In order to increase the cooling intensity at the connection point between the old and new billets after exiting the crystallizer, the water flow rate in each flow foot roller area is increased by 100 L / min after the tundish starts pouring. Normal flow rate is restored after the pouring length exceeds 1000 mm after the start of pouring.

[0016] 3) Slag Removal: After the old tundish stops casting, a ring of slag will form around the surface of the crystallizer. This ring needs to be removed and cleaned thoroughly to ensure a firm connection between the old and new billet shells. Design a slag removal rake and slag ring removal tools.

[0017] 4) Quick ladle change process rhythm control: During the ladle change process, after the old tundish's tail furnace ladle has finished pouring the steel for the previous process, when the old tundish has 18-20t of steel remaining, the ladle change program is activated. When the remaining steel is 12t, the new tundish is checked. When the remaining steel is 6-8t, the old tundish stops pouring and moves the ladle, and the ladle change operation begins. Pouring begins when the new tundish has 25t of molten steel, ensuring the tundish liquid level is maintained at the start of pouring.

[0018] 5) There may be a risk of steel leakage during the quick tundish change process. Small openings that can be closed are made on one side of the crystallizer cover plate. These openings are opened before the tundish change and closed after the change is completed normally. This is used to observe the condition of the second cooling zone during the tundish pouring process. If steel splashing is found, it can be judged that steel leakage has occurred, which can facilitate timely manual operation and handling.

[0019] 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.

[0020] The above are merely specific embodiments 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 quick-change tundish in continuous casting of round billets of specification Ф390, characterized in that, include: 1) Connector design; The upper and lower cross sections of the connector are circular, the upper diameter of the connector is 330mm, the lower diameter of the connector is 227mm, the height of the connector is 500mm, the connector has an inverted conical structure, and 8 springs are welded to the outer ring of the connector; 2) Adjustment of process parameters during quick intermediate package changeover; The starting speed and initial pouring speed of the Ф390 specification round billet is 0.25m / min. After the tundish starts pouring, the water flow rate in each flow foot roller area increases by 100L / min compared to the previous water flow rate. After the length of the Ф390 specification round billet poured after the start of pouring is greater than 1000mm, the water flow rate is consistent with the previous flow rate. 3) Slag removal; After the old tundish stops casting, a slag ring forms around the slag surface of the crystallizer. The slag ring is then removed. 4) Quick change process rhythm control: When the old tundish is finished pouring the ladle in the tail furnace and the previous process is tapped, the ladle change program is activated when there are 18-20t of steel remaining in the old tundish. When there are 12t of steel remaining, the new tundish is checked. When there are 6-8t of steel remaining, the old tundish stops pouring and moves the car to start the ladle change operation. When the new tundish has 25t of molten steel, start pouring and ensure the tundish liquid level at the start of pouring. 5) Make a small, closable opening on each side of the crystallizer cover plate. Open it before changing the packing and close it after changing the packing.