JPH0562565U - Coil plate for box annealing - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a coil plate such as a spacer or convector plate that can perform box annealing of a coil with significantly reduced seizure defects and improved annealing yield. An annular groove 7 having an inner diameter smaller than the coil inner diameter and an outer diameter larger than the coil outer diameter is provided on the coil mounting side of a coil plate 4 having an atmosphere gas flow hole 6 in the center, and the annular groove 7 is heat-resistant. Coil plate 4 for box annealing, in which a lump 8 of metal or ceramics having heat resistance is spread.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a coil plate for box annealing that prevents seizure in the coil in box annealing (batch type annealing) of thin steel plate coils such as ordinary steel plates and electromagnetic steel plates.

A strip steel sheet obtained by cold rolling a hot-rolled steel sheet into a coil shape has a spacer or a spacer on a base plate in order to improve workability or characteristics required for a thin steel sheet such as electromagnetic characteristics. Stacked in several stages via a coil plate such as a convector plate, covered with an inner cover sealed with atmospheric gas mainly containing nitrogen and hydrogen, and placed a heating device on the outside. A box anneal is performed with a cover over and heating to recrystallization temperature and cooling.

In the coil thus annealed in a box, there is a problem that a contact defect (a seizure defect) between adjacent strips called a seizure occurs at a portion in contact with the coil plate. Seizure flaws are caused by two factors: local pressure concentration on the coil end surface and exposure to high temperature.A phenomenon that is particularly noticeable in thin or soft strip coils, and is a product product. There was a problem of causing a decrease in value and yield.

[0004]

[Prior Art]

 For this reason, as a method of preventing the occurrence of seizure flaws, for example, as disclosed in Japanese Patent Publication No. 46-27924, a coil having a base plate having a large number of atmosphere vent holes on a plate surface is arranged in an inner cover. Annealing furnace ", Japanese Patent Publication No. 46-27928," Convector plate with a taper formed on the outer peripheral portion or the inner peripheral portion of a plate ", and Japanese Utility Model Publication No. 46-29528," A hole is formed in the central portion and Many types of plates have been developed, such as a "convector plate with a wavy circular cross-section whose ridges extend radially from the center toward the outer circumference," but the material is made of cast steel and is flat. , The flat surface is maintained during the first annealing, but in the annealing after the second annealing, a slight deformation occurs at high temperature and uneven pressure concentration is generated at the coil end, causing seizure defects. There was a problem.

More recently, as disclosed in Japanese Patent Application Laid-Open No. 61-56249, "By applying boron nitride or powdered chromium having a good lubricity to the coil pedestal, the lower end of the coil during annealing and the coil support are A coil box annealing method has also been developed, which uses the role of a roller that avoids direct contact of the table and moderates the friction that occurs when the two expand and contract. This method also has a problem that a uniform coating layer is required, and that coating work and peeling removal work are newly added, which is a troublesome work.

[0006]

[Problems to be solved by the device]

 In view of these problems, the present invention has an object to provide a coil plate such as a spacer or a convector plate capable of box annealing of a coil with significantly reduced seizure defects and improved annealing yield.

[0007]

[Means and Actions for Solving the Problems]

 The gist of the present invention is to provide an annular groove having an inner diameter smaller than the coil inner diameter and an outer diameter larger than the coil outer diameter on the coil mounting side of a coil plate having an atmosphere gas passage hole in the center, and the annular groove having heat resistance. It is a coil plate for box annealing, in which a lump of metal or ceramic having the above is spread.

Hereinafter, the present invention will be described in detail. 1 and 2 show an embodiment of the present invention in a box annealing furnace. In FIG. 1, reference numeral 1 is a coil pedestal, which is provided on the furnace bottom 2. Reference numeral 3 is an atmospheric gas supply pipe. Reference numeral 4 denotes a coil plate, which is placed between the coil cradle 1 or the coil 5 and the coil 5'which are stacked and annealed. As shown in FIG. 2, the coil plate 4 has an atmospheric gas passage hole 6 in the center thereof, and has an annular groove 7 on the side wall whose inner diameter is smaller than the inner diameter of the coil 5 to be annealed and whose outer diameter is larger than the coil outer diameter. A lump 8 of iron, steel or other metal or ceramics that can withstand the annealing temperature is provided in the annular groove 7 by partitioning it with a cross frame 9 if necessary.

At the bottom of the coil plate 4, an atmosphere of a size that does not cause the lump 8 to fall so that the atmosphere gas introduced from the atmosphere gas supply pipe 3 easily flows through the narrow gap in the coil 5. Gas through holes may be provided. Reference numeral 10 denotes an inner cover, which is covered with an outer cover (not shown) having a heating device arranged on the outer side thereof. Reference numeral 11 denotes a seal portion, which prevents the atmospheric gas introduced into the inner cover 10 from leaking to the outer cover and is generally used such as a sand seal or a mechanical seal structure.

After placing the coil plate 4 of the present invention as described above between the coil cradle 1 or the coil 5 to be further annealed, the inner cover 10 and then the outer cover are covered, and then the atmosphere gas flow hole 6 is used. While introducing an atmosphere gas such as nitrogen gas or nitrogen containing hydrogen into the inner cover 10, a normal annealing work is performed in which the outer cover is heated to a predetermined temperature.

The coil thus annealed is uniformly heated because the high temperature heat locally rising at the lower end of the coil is radiated through the small gaps between the individual lumps 8. Deformation of the lower end of the coil that follows the rise and fall of the annealing temperature is also mitigated by the movement of individual lumps 8 and a coil having good formability with improved annealing yield is manufactured.

[0012]

【Example】

 A coil plate, in which steel balls (8 mmφ) are laid in an annular groove, is placed on the coil pedestal, and a coil having a plate thickness of 0.21 × a plate width of 1030 mm and a weight of 10 t is placed on the coil plate at 5 ° C at 700 ° C. Box annealing was performed so that the temperature was soaked for an hour. On the other hand, coils of the same size were annealed under the same annealing conditions using the conventional coil plate described in Japanese Utility Model Publication No. 46-29528, and the seizure difference between the two was compared. The results are shown in Table 1.

[0013]

[Table 1]

[0014]

【The invention's effect】

 As is clear from Table 1, the present invention significantly improved seizure flaws and reduced the yield loss due to seizure to 1/10 or less.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are views showing an embodiment of the present invention.

[Explanation of symbols]

1: Coil holder, 2: Furnace bottom, 3: Atmosphere gas supply pipe, 4: Coil plate, 5, 5 ': Annealed coil, 6: Atmosphere gas flow hole, 7: Annular groove,
8: lump, 9: cross frame, 10: inner cover,
11: Seal part.

Claims (1)

[Scope of utility model registration request] 1. An annular groove having an inner diameter smaller than the coil inner diameter and an outer diameter larger than the coil outer diameter is provided on the coil mounting side of a coil plate having an atmosphere gas flow hole in the center, and the annular groove is provided with heat resistance. A coil plate for box annealing, which is characterized by being filled with a lump of metal or ceramics.