JP5765328B2 - Cold rolling equipment and cold rolling method - Google Patents

Description

  The present invention relates to a cold rolling facility and a cold rolling method.

The manufacturing process of the cold-rolled high carbon special steel strip is roughly divided into the following three patterns of manufacturing processes using hot-rolled pickling material.
(1) Primary annealing → rolling → electrolytic cleaning → secondary annealing → temper rolling → refining → shipping (2) rolling → electrolytic cleaning → annealing → refining rolling → refining → shipping (3) annealing → rolling → electrolytic cleaning → Refinement → Shipment When the equipment that performs electrolytic cleaning and annealing is a continuous processing equipment, a preceding steel is used by a welding machine provided in the preceding stage of the continuous processing equipment so that cleaning and annealing can be performed continuously. The end of the strip and the tip of the subsequent steel strip are joined sequentially by welding and supplied to a continuous processing facility as a continuous material.

  Here, when the maximum thickness that can be joined by the welder is smaller than the maximum thickness that can be processed by other equipment, the maximum thickness that can be produced by the equipment is determined by the welding machine capacity neck. The maximum thickness that can be joined by the machine is determined.

  Therefore, if you want to increase the maximum thickness of the steel strip that can be manufactured with existing manufacturing equipment, invest in the welding machine that becomes the manufacturing bottleneck, replace it with new equipment, modify the existing equipment, You must improve your ability. However, replacement with new equipment or modification of existing equipment is difficult due to cost and installation space problems. Furthermore, in cold-rolled special steel welding, increasing the weldable plate thickness has to increase the amount of heat input during welding, increasing the risk of steel plate breakage due to quench hardening of the weld. Problems also add.

  The present invention has been made to solve the above-described problems, and can expand the manufacturable range of the thickness of the steel strip that can be manufactured without making capital investment, and can improve productivity. An object is to provide a cold rolling facility and a cold rolling method.

The present invention has the following features in order to achieve the above object.
[1] A cold rolling mill for producing a steel strip in which at least one end of a steady plate thickness portion to be a product is formed with a thickness minus portion having a thickness smaller than the steady plate thickness portion by rolling,
The plate thickness of the steady plate thickness portion is the maximum plate thickness that can be processed by a welder that is provided in a subsequent process of the cold rolling mill and connects an end of the steel strip to another steel strip or a jumper material. Thicker than
The cold rolling equipment characterized in that the plate thickness minus the plate thickness is equal to or less than the maximum plate thickness that can be processed by the welding machine.
[2] The cold rolling equipment according to [1], wherein the length of the sheet thickness minus part is set to a length of a defective portion generated in a subsequent process of the cold rolling mill.
[3] The cold rolling equipment according to [1] or [2], wherein the plate thickness of the steady plate thickness portion is equal to or less than twice the minimum plate thickness of the plate thickness minus portion.
[4] At least one end of the steady plate thickness portion to be a product is manufactured by a cold rolling mill with a steel strip in which a plate thickness minus portion having a thickness smaller than the steady plate thickness portion is formed by rolling,
The plate thickness of the steady plate thickness portion is the maximum plate thickness that can be processed by a welder that is provided in a subsequent process of the cold rolling mill and connects an end of the steel strip to another steel strip or a jumper material. Thicker than
The cold rolling method according to claim 1, wherein the plate thickness minus the plate thickness is equal to or less than the maximum plate thickness that can be processed by the welding machine.
[5] The cold rolling method according to [4], wherein a length of the sheet thickness minus part is set to a length of a defective part generated in a subsequent process of the cold rolling mill.
[6] The cold rolling method according to [4] or [5], wherein the plate thickness of the steady plate thickness portion is not more than twice the minimum plate thickness of the plate thickness minus portion.

  In the cold rolling equipment and the cold rolling method according to the present invention, the production range of the thickness of the steel strip that can be manufactured is expanded and the productivity is improved without investing in equipment for the welding machine. Can do.

It is a figure which shows the outline | summary of the cold rolling equipment which concerns on embodiment of this invention. It is a figure which shows the cross section of the longitudinal direction of the steel strip manufactured by the rolling mill of the cold rolling equipment which concerns on embodiment of this invention. As an example of productivity improvement according to an example of the present invention, it is a diagram showing the relationship between the ECL dirt length (steady board part, board thickness minus part), ECL cut-off weight, and ECL dirt yield.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an outline of a cold rolling facility according to an embodiment of the present invention.

  As shown in FIG. 1, the cold rolling equipment includes a cold rolling mill 11, a cutting machine 12, a welding machine 13, an electrolytic cleaning equipment 14, and a cutting machine 15.

  The cold rolling mill 11 rolls a steel strip to produce a steady plate thickness portion 21 that is a product, and at least one end of the steady plate thickness portion 21, a plate thickness minus portion that is thinner than the steady plate thickness portion 21. 22 is formed (see FIG. 2A). The cold rolling mill 11 may be a tandem type or a reverse type, but here, it will be described as a reverse type rolling mill. The reverse rolling mill has a feature that it is easier to control the rolling of the front and rear ends of the steel strip than the tandem rolling mill. As shown in FIG. 2A, unrolled portions 23 that are not rolled at both ends remain in the steel strip rolled by the reverse rolling mill.

  The cutting machine 12 cuts the unrolled part 23 that has not been rolled.

  The welding machine 13 joins the end of the preceding steel strip and the tip of the following steel strip by welding sequentially. In addition, you may weld a jumper material to a preceding steel strip instead of a steel strip according to steel materials. It is assumed that the welding machine 12 is a manufacturing facility having the smallest maximum thick plate that can be processed in the cold rolling facility, and is a facility that becomes a manufacturing neck of a plate thickness that can be manufactured in the cold rolling facility. Hereinafter, the maximum plate thickness that can be processed in the welding machine 12 is T.

  The electrolytic cleaning equipment 14 is supplied with a continuous steel strip in which a plurality of steel strips are welded by a welding machine 13. The electrolytic cleaning equipment 14 cleans oil stains such as rolling oil and rust preventive oil adhered to the surface of the steel strip, solid stains such as iron powder, and the like by passing a current through the steel strip. The electrolytic cleaning equipment 14 is held in a state in which a portion of about several tens of meters from the end is immersed in the cleaning liquid for a few minutes when the preceding steel strip and the subsequent steel strip are welded by the welding machine 12 in the previous stage. Is done. Since a portion of about several tens of meters from this end is immersed in the cleaning liquid, an oxide film (rust) is generated on the surface.

  The cutting machine 15 cuts the portion where the oxide film is generated as a defective portion. Thereby, the washed steel strip is manufactured.

  Next, a cold rolling method using such a cold rolling facility will be described. FIG. 2 is a diagram showing the state of the steel strip in each step of the cold rolling method according to the embodiment of the present invention. The left and right sides of the paper are the longitudinal direction of the steel strip, and the top and bottom of the paper are the thickness direction of the steel strip.

  First, as shown in FIG. 2A, a steel strip is rolled by a cold rolling mill 11, and a plate thickness that is thinner than the steady plate thickness portion 21 is provided at both ends of the steady plate thickness portion 21 to be a product. A minus part 22 is formed. The plate thickness a of the steady plate thickness portion 21 is thicker than the maximum plate thickness T that can be processed by the welding machine 12, and the plate thickness b of the plate thickness minus portion 22 is equal to or less than the maximum plate thickness T.

  The plate thickness a of the steady plate thickness portion 21 is preferably not more than twice the minimum plate thickness of the plate thickness minus portion 22. If the steady plate thickness portion 21 is less than or equal to twice the minimum plate thickness of the plate thickness minus portion 22, the steel strip tension can be easily controlled.

  Further, as described above, the steel strip rolled by the cold rolling mill 11 has unrolled portions 23 that are not rolled at the front and rear ends.

  The length L of the plate thickness minus portion 22 is preferably the length of a defective portion where an oxide film is generated in the electrolytic cleaning equipment 14. For example, in the electrolytic cleaning equipment 14, when the length of the defective portion generated at the end of the steel strip is 40 m, the length L of the plate thickness minus portion 22 is set to about 40 m. This defective portion is cut by the cutting machine 15. By configuring the plate thickness of the defective portion with the plate thickness minus portion 22, it is possible to reduce the loss in terms of the weight of the steel strip as compared with the case where the entire length is configured as the steady plate thickness portion 21. There is an effect.

  Next, as shown in FIG.2 (b), the unrolled part 23 of the both ends of a steel strip is cut | disconnected by the cutting machine 12. FIG.

  Then, as shown in FIG. 2 (c), the plate thickness minus portion 22 at the end of the preceding steel strip is joined to the plate thickness minus portion 22 at the tip of the subsequent steel strip by the welding machine 13. Since the plate thickness minus part 22 welded by the welder 13 is equal to or less than the maximum plate thickness T that can be welded by the welder 13, the steel strips can be joined by the welder 13. The welding machine 13 sequentially performs this welding operation.

  The steel strip connected by the welding machine 13 is passed through the electrolytic cleaning equipment 14 which is a continuous processing equipment, and then the plate thickness minus part 22 is cut by the cutting machine 15.

  Thus, in the cold rolling equipment and the cold rolling method according to the present embodiment, the welding machine 13 can be welded to both ends of the steady plate thickness portion 21 that is larger than the maximum plate thickness T that can be welded by the welding machine 13. By forming the thickness minus portion 22 that is equal to or less than the maximum thickness T, a steel strip that is thicker than the maximum thickness T that can be welded by the welding machine 13 can be passed through the welding machine 13. Thereby, without making capital investment in the welding machine 13, the manufacturable range of the plate thickness of the steel strip that can be manufactured can be expanded and the productivity can be improved.

  Further, in the cold rolling equipment and the cold rolling method according to the present embodiment, the length L of the sheet thickness minus portion 22 is set to a length that is cut as a defective portion in a subsequent process. Since the plate thickness minus portion 22 is thinner than the steady plate thickness portion 21, it is possible to reduce the plate thickness of unnecessary portions and reduce the loss in terms of the weight of the steel strip. Thereby, productivity can be further improved.

  In FIG. 2B, plate thickness minus portions 22 are formed at both ends of the steady plate thickness portion 21, but the plate thickness minus portions 22 are not necessarily provided at both ends of the steady plate thickness portion 21. It may be formed at least at one end. For example, when a plurality of coils are connected by the welder 13, the tip of the first coil and the rear end of the last coil are not welded by the welder 12, and are rolled by the cold rolling mill 11. There is no need.

  Examples of the present invention will be described. The cold rolling equipment according to the embodiment was applied to existing equipment. As a result, the plate thickness of the steel strip that can be manufactured in the existing cold rolling equipment could be increased from the conventional 1.6 mm determined by the manufacturing neck of the welding machine to 3.2 mm.

  FIG. 3 is a diagram showing the relationship between the ECL stain length (steady plate portion, plate thickness minus portion), the ECL cut-off weight, and the ECL stain yield as an example of productivity improvement according to the present invention. The horizontal axis indicates the ECL stain length (steady plate thickness portion) and the ECL stain length (plate thickness minus portion).

  In the example, a coil having a steady plate thickness after cold rolling of 2.0 mm, a plate thickness minus 1.6 mm, a plate width of 94 cm, and a coil weight of 12 ton was washed with ECL. In this ECL, ECL contamination of 80 m in total is generated at each of the front end and the rear end of the coil.

  The left end of FIG. 3 shows the case where the minus thickness portion is not connected to the steady plate thickness portion. In this case, the ECL stain length (steady plate thickness portion) is 80 m, and the ECL stain length (plate thickness minus). Part) is 0 m. At this time, the cut-off weight of ECL dirt is 1.17 tons, and the yield due to ECL dirt is 9.8%.

  On the other hand, the right end of FIG. 3 shows a case where a plate thickness minus portion having a plate thickness of 1.6 mm is connected to the front end and the rear end of the steady plate thickness portion by 40 m. In this case, the ECL stain length (steady plate thickness portion) is 0 m, and the ECL stain length (plate thickness minus portion) is 80 m. At this time, the weight of ECL dirt cut off is 0.94 tons, and the yield due to ECL dirt is 7.8%.

  From the above, it has been found that by forming a plate thickness minus portion at the end of the steady plate thickness portion, it is possible to reduce the ECL dirt cut weight and improve the yield.

DESCRIPTION OF SYMBOLS 11 Cold rolling machine 12 Cutting machine 13 Welding machine 14 Electrolytic cleaning equipment 15 Cutting machine 21 Steady plate thickness part 22 Sheet thickness minus part 23 Unrolled part

Claims (7)

A cold rolling mill for producing a steel strip in which at least one end of a steady plate thickness portion to be a product is formed with a plate thickness minus portion having a thickness smaller than the steady plate thickness portion by rolling ;
Thickness of the constant thickness portion, the cold provided subsequent step of the rolling mill, the end portion of the steel strip, the maximum thickness workable welding machine to be connected to the other strip or ties Thicker than
The plate thickness of the thick negative portions, the cold rolling equipment, characterized in that a control device for controlling such that less than the maximum thickness that can be processed in the welding machine.   2. The cold rolling equipment according to claim 1, wherein a length of the sheet thickness minus part is set to a length of a defective portion generated in a subsequent process of the cold rolling mill.   The cold rolling equipment according to claim 1 or 2, wherein a plate thickness of the steady plate thickness portion is not more than twice a minimum plate thickness of the plate thickness minus portion. At least one end of the steady plate thickness portion to be a product, a steel strip in which a plate thickness minus portion having a thickness smaller than the steady plate thickness portion is formed by rolling is manufactured by a cold rolling mill,
The plate thickness of the steady plate thickness portion is the maximum plate thickness that can be processed by a welder that is provided in a subsequent process of the cold rolling mill and connects an end of the steel strip to another steel strip or a jumper material. Thicker than
The cold rolling method according to claim 1, wherein the plate thickness minus the plate thickness is equal to or less than the maximum plate thickness that can be processed by the welding machine.   5. The cold rolling method according to claim 4, wherein the length of the sheet thickness minus part is set to a length of a defective portion generated in a subsequent process of the cold rolling mill.   The cold rolling method according to claim 4 or 5, wherein a plate thickness of the steady plate thickness portion is not more than twice a minimum plate thickness of the plate thickness minus portion. The manufacturing method of the cold rolled steel strip using the cold rolling method in any one of Claims 4 thru | or 6.

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