Continuous rolling system and continuous rolling method for double-phase high-strength steel and application

Abstract

The invention belongs to the technical field of strip steel rolling, and particularly relates to a continuous rolling system and method for double-phase high-strength steel and application. The continuous rolling method comprises the following steps that a plurality of original steel coils are subjected to end-to-end laser welding to obtain a total steel coil, and in laser welding, the laser power ranges from 6 kW to 8 kW, the welding speed ranges from 6.0 m / min to 6.5 m / min, the wire feeding speed ranges from 5.9 m / min to 6.3 m / min, and the annealing power ranges from 2.8 kW to 3.2 kW; the total steel coil is subjected to acid pickling continuous rolling; and after continuous rolling, only parts with thickness difference at the head end and the tail end of the total steel coil need to be cut off, so that the problem of reduction of the yield caused by cutting due to the thickness difference between the head end and the tail end of the strip steel after rolling of each steel coil is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of strip steel rolling, and in particular relates to a continuous rolling system and continuous rolling method for dual-phase high-strength steel and applications thereof. Background Art

[0002] Duplex high-strength steel is a kind of steel that combines the characteristics of austenitic stainless steel and ferritic stainless steel. It has excellent mechanical properties and corrosion resistance. Its unique properties make it widely used in heavy-duty structures, highways, automobile manufacturing, aerospace and other fields.

[0003] At present, the continuous rolling of dual-phase high-strength steel is hot rolling or cold rolling. The cold rolling steps generally include push-pull pickling, single-stand rolling and galvanizing to obtain cold-rolled coils. In this continuous rolling method, each coil needs to be cut at the head and tail during push-pull pickling, which will cause a certain loss in yield rate; after rolling in a single-stand reversible rolling mill, there is a thickness difference between the head and tail of the strip, which needs to be cut off in the last rolling pass, further reducing the yield rate. In addition, the plate shape control ability of a single stand is poor compared to that of a continuous rolling 5-stand, which has a certain impact on the smooth production of the galvanizing process. The galvanized products produced through this production process path (such as H780DPD) have high costs and low yield rates. Summary of the invention

[0004] The present invention provides a dual-phase high-strength steel continuous rolling system and continuous rolling method and application to solve at least one aspect of the above technical problems.

[0005] The present invention is achieved through the following technical solutions:

[0006] A first aspect of the present invention provides a method for continuous rolling of dual-phase high-strength steel, comprising the following steps:

[0007] The head and tail of several original steel coils are laser welded to obtain a total steel coil, wherein in the laser welding: the solder is the original steel coil itself, the laser power is 6kW to 8kW, the welding speed is 6.0m / min to 6.5m / min, the wire feeding speed is 5.9m / min to 6.3m / min, and the annealing power is 2.23kW to 3.2kW;

[0008] The total steel coil is pickled and continuously rolled.

[0009] In some possible implementations, the difference in thickness between the head and tail of the strip obtained after pickling and continuous rolling is less than 1.1 mm.

[0010] In some possible implementations, the width difference between the head and tail of the strip obtained after pickling and continuous rolling is less than 300 mm.

[0011] In some possible implementations, the thickness deviation rate of the strip head and tail obtained after the pickling and continuous rolling is less than 30%.

[0012] In some possible implementations, in the laser welding, the laser welding machine selected is a GD-10C-1620 laser welding machine.

[0013] In some possible implementations, the number of coils of the original steel coil is more than 2.

[0014] In some possible implementations, the continuous rolling method further includes the step of: slicing the steel coil obtained by pickling and continuous rolling into a plurality of rolled steel coils, and then subjecting the steel coils to galvanizing.

[0015] In some possible implementations, the number of coils of the steel coil after pickling and continuous rolling is not less than the number of coils of the original steel coil.

[0016] The second aspect of the present invention provides a continuous rolling system for the continuous rolling method of the dual-phase high-strength steel provided above, characterized in that it includes a welding unit for laser welding the ends of two original steel coils and a rolling unit for the total steel coil obtained by rolling and welding.

[0017] A third aspect of the present invention provides an application of the continuous rolling method of dual-phase high-strength steel provided by the present invention in the field of dual-phase high-strength steel production.

[0018] The continuous rolling method of dual-phase high-strength steel provided by the present invention has at least the following beneficial technical effects compared with the prior art:

[0019] (1) The continuous rolling method of the dual-phase high-strength steel of the present invention first uses laser welding of the ends of several original steel coils into a large total steel coil, and then pickling and continuous rolling are performed. After continuous rolling, only the parts with thickness difference at the ends of the total steel coil need to be cut off, and the yield rate is 90% to 95%. Compared with the single-coil rolling of several original steel coils, the yield rate is reduced by cutting off each steel coil after rolling due to the thickness difference between the ends of the strip steel. The yield rate of the continuous rolling method of the dual-phase high-strength steel of the present invention is increased by 5% to 8%.

[0020] (2) The continuous rolling method of the dual-phase high-strength steel in the embodiment of the present invention adopts laser welding, and the ends of two adjacent steel coils can be directly welded together without using additional solder, thereby improving the compatibility between the steel coils.

[0021] (3) The continuous rolling method of the dual-phase high-strength steel according to the embodiment of the present invention can achieve continuous and stable production on a pickling continuous rolling mill, thereby improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0023] Figure 1 This is a schematic structural diagram of a dual-phase high-strength steel continuous rolling system according to an embodiment of the present invention;

[0024] Figure 1a This is a metallographic diagram of a steel coil in a continuous rolling method of a dual-phase high-strength steel in Example 1 of the present invention;

[0025] Figure 1b This is a schematic diagram of a weld structure in a continuous rolling method of dual-phase high-strength steel in Example 1 of the present invention;

[0026] Figure 1c This is a metallographic diagram of a weld in a continuous rolling method of a dual-phase high-strength steel in Example 1 of the present invention;

[0027] Figure 1d It is a structural diagram of a weld after annealing in a continuous rolling method of a dual-phase high-strength steel in Example 1 of the present invention and a corresponding bending test schematic diagram;

[0028] Figure 2a This is a metallographic diagram of a steel coil in a continuous rolling method of dual-phase high-strength steel in Example 2 of the present invention;

[0029] Figure 2b Schematic diagram of a weld structure in a continuous rolling method of dual-phase high-strength steel in Example 2 of the present invention;

[0030] Figure 2c A metallographic diagram of a weld in a continuous rolling method of a dual-phase high-strength steel in Example 2 of the present invention;

[0031] Figure 2d A structural diagram of a weld after annealing in a continuous rolling method of a dual-phase high-strength steel in Example 2 of the present invention and a corresponding bending test schematic diagram;

[0032] Figure 3a This is a metallographic diagram of a steel coil in a continuous rolling method of dual-phase high-strength steel in Example 3 of the present invention;

[0033] Figure 3b This is a schematic diagram of a weld structure in a continuous rolling method of dual-phase high-strength steel in Example 3 of the present invention;

[0034] Figure 3c A metallographic diagram of a weld in a continuous rolling method of a dual-phase high-strength steel in Example 3 of the present invention;

[0035] Figure 3d It is a structural diagram of a weld after annealing in a continuous rolling method of a dual-phase high-strength steel in Example 3 of the present invention and a corresponding bending test schematic diagram.

[0036] Explanation of the accompanying drawings: 1-strip entry looper roller, 2-entrance pinch roller, 3-first centering device, 4-entrance clamping device, 5-second centering device, 6-welding trolley, 7-exit clamping device, 8-third centering device, 9-crescent shears, 10-fourth centering device, 11-exit pinch roller, 12-exit looper roller, 13-rolling unit.

[0037] The purpose, features and advantages of this figure will be further described in conjunction with the embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described and illustrated in conjunction with the embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0039] Obviously, the following descriptions are only some examples or embodiments of the present invention, and for those of ordinary skill in the art, the present invention can also be applied to other similar scenarios without creative work. In addition, it can also be understood that although the efforts made in such a development process may be complex and lengthy, for those of ordinary skill in the art related to the contents disclosed in the present invention, some changes in design, manufacturing or production based on the technical contents disclosed in the present invention are just conventional technical means, and should not be understood as the contents disclosed in the present invention being insufficient.

[0040] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present invention and is not intended to limit the subject matter described in the claims.

[0041] If not otherwise specified, all embodiments and optional embodiments of the present invention may be combined with each other to form a new technical solution, and all technical features and optional technical features of the present invention may be combined with each other to form a new technical solution.

[0042] A first aspect of an embodiment of the present invention provides a method for continuous rolling of dual-phase high-strength steel, comprising the following steps:

[0043] S1. The head and tail of several original steel coils are laser welded to obtain a total steel coil, wherein in laser welding: the solder is the original steel coil itself, the laser power is 6kW to 8kW, the welding speed is 6.0m / min to 6.5m / min, the wire feeding speed is 5.9m / min to 6.3m / min, and the annealing power is 2.23kW to 3.2kW;

[0044] S2. The total steel coil is pickled and continuously rolled.

[0045] The continuous rolling method of dual-phase high-strength steel provided in an embodiment of the present invention first uses laser welding at the ends of several original steel coils to form a large total steel coil, and then performs pickling and continuous rolling. After continuous rolling, only the parts with thickness difference at the ends of the total steel coil need to be cut off, and the yield rate is 90% to 95%. Compared with the single-coil rolling of several original steel coils, the yield rate is reduced due to the cutting off of each steel coil after rolling due to the thickness difference at the ends of the strip. The yield rate of the continuous rolling method of dual-phase high-strength steel of the present invention is increased by 5% to 8%.

[0046] In some specific embodiments, in the above step S1, in the laser welding, the laser welding machine selected is a GD-10C-1620 laser welding machine.

[0047] In the GD-10C-1620 laser welding machine, GD stands for solid laser; 10C stands for laser power of 10KW; and 1620 stands for the maximum nominal width in mm.

[0048] In some specific embodiments, in the above step S1, the technical parameters of the GD-10C-1620 laser welding machine include:

[0049] Welding machine type C, double-edged metal shears inside the machine, fully automatic;

[0050] Welding method: solid laser welding (laser power range 10KW);

[0051] Welding seam treatment: preheating, annealing heating, and wire filling treatment;

[0052] Welding capacity 1.0mm~6.0mm (10% deviation between head and tail);

[0053] The welding direction is perpendicular to the center of the continuous rolling mill, from the operating side to the transmission side.

[0054] In some embodiments, in the above step S1, the original steel coil is dual-phase high-strength steel H780DPD.

[0055] In some embodiments, in the above step S1, the number of coils of the original steel coil is 2 or more, preferably 2 to 5 coils.

[0056] In some embodiments, in the above step S2, the thickness difference between the head and tail of the strip obtained after pickling and continuous rolling is less than 1.1 mm.

[0057] In some embodiments, in the above step S2, the width difference between the head and tail of the strip obtained after pickling and continuous rolling is less than 300 mm.

[0058] In some embodiments, in the above step S2, the thickness deviation rate of the strip obtained after pickling and continuous rolling is less than 30%.

[0059] Among them, h2 is the thick position and h1 is the thin position.

[0060] In some embodiments, the continuous rolling method further comprises the step of: slicing the steel coil obtained by pickling and continuous rolling into a plurality of rolled steel coils, and then galvanizing. In this case, when the steel coil after continuous rolling is sliced, there is no large thickness difference between the beginning and the end of the sliced ​​steel coils, so that no further cutting is required, thereby improving the yield rate of the steel.

[0061] In some embodiments, the number of coils of the steel coil after pickling and continuous rolling is not less than the number of coils of the original steel coil.

[0062] A second aspect of the present invention provides a continuous rolling system for implementing the continuous rolling method of the dual-phase high-strength steel provided above, such as Figure 1 As shown, it includes a welding unit for laser welding the ends of two original steel coils and a rolling unit for rolling the total steel coil obtained by welding.

[0063] The continuous rolling system for dual-phase high-strength steel provided in the embodiment of the present invention can realize subsequent pickling and continuous rolling after a number of original steel coils are laser welded at the head and tail of the welding unit to obtain a total steel coil, thereby improving the yield rate of the dual-phase high-strength steel.

[0064] In some embodiments, the welding unit includes: an entry looper roller for the strip, an entry pinch roller, a first centering device, an entry clamping device, a second centering device, a welding carriage, an exit clamping device, a third centering device, a crescent shear, a fourth centering device, an exit pinch roller, and an exit looper roller;

[0065] The second centering device is located in the inlet clamping device; the third centering device is located in the outlet clamping device;

[0066] The original steel coil enters the rolling unit after passing through the strip steel entrance looper roller, entrance pinch roller, first centering device, entrance clamping device, second centering device, welding trolley, exit clamping device, third centering device, crescent shear, fourth centering device, exit pinch roller and exit looper roller. It should be noted that the structures of the strip steel entrance looper roller, entrance pinch roller, first centering device, entrance clamping device, second centering device, welding trolley, exit clamping device, third centering device, crescent shear, fourth centering device, exit pinch roller and exit looper roller in the welding unit are all existing devices in the art, and are not particularly limited in the embodiments of the present invention; and the rolling unit is a rolling mill commonly used in the existing cold rolling and hot rolling processes of steel coils, and is not particularly limited in the embodiments of the present invention.

[0067] A third aspect of the embodiments of the present invention provides an application of the continuous rolling method of dual-phase high-strength steel provided in the embodiments of the present invention in the field of dual-phase high-strength steel production.

[0068] The following is further described in conjunction with specific embodiments.

[0069] Example 1

[0070] Embodiment 1 provides a method for continuous rolling of dual-phase high-strength steel, the steps of which are as follows:

[0071] S10. Figure 1 As shown, a GD-10C-1620 laser welding machine is used to laser weld 5 rolls of H780DPD original steel coils into one total steel coil, wherein the solder is H780DPD self-welding, the laser power is 7.63kW, the welding speed is 6.08m / min, the wire feeding speed is 6.31m / min, and the annealing power is 2.97kW.

[0072] S20. The total steel coil is pickled and continuously rolled.

[0073] This embodiment also provides a continuous rolling system for implementing the continuous rolling method of the dual-phase high-strength steel provided in this embodiment, such as Figure 1 As shown, it consists of a welding unit and a rolling unit;

[0074] The welding unit includes: strip inlet looper roller, inlet pinch roller, first centering device, inlet clamping device, second centering device, welding carriage, outlet clamping device, third centering device, crescent shear, fourth centering device, outlet pinch roller and outlet looper roller;

[0075] The second centering device is located in the inlet clamping device; the third centering device is located in the outlet clamping device;

[0076] The original steel coil enters the rolling unit after passing through the strip entrance looper roller, entrance pinch roller, first centering device, entrance clamping device, second centering device, welding trolley, exit clamping device, third centering device, crescent shear, exit pinch roller and exit looper roller.

[0077] Example 2

[0078] Example 2 provides a continuous rolling method for dual-phase high-strength steel, the steps are basically the same as those of Example 1, except that:

[0079] The annealing power is 2.52kW.

[0080] Example 3

[0081] Example 3 provides a continuous rolling method for dual-phase high-strength steel, the steps are basically the same as those of Example 1, except that:

[0082] The annealing power is 2.23kW.

[0083] Comparative Example 1

[0084] Comparative Example 1 provides a continuous rolling method for dual-phase high-strength steel, the steps are as follows:

[0085] (1) Select 5 original steel coils.

[0086] (2) The five original steel coils are pickled, continuously rolled and then galvanized.

[0087] In order to verify the progressiveness of the continuous rolling method of dual-phase high-strength steel provided in the embodiment of the present invention, bending tests were carried out on the steel coils obtained by rolling in the embodiment and the comparative example according to the standard GB / T232. The bending conditions of the bent steel coils corresponding to the weld seams are shown in the attached manual. Figure 1d , Figure 2d and Figure 3d According to the standard GB / T 4156, the weld cupping test was carried out on the welds of Examples 1 to 3, and the base metal and weld of the steel coil obtained after welding were subjected to metallographic inspection. The metallographic diagram and the structure of the weld are shown in the attached manual. Figure 1a , Figure 1b , Figure 1c , Figure 2a , Figure 2b , Figure 2c , Figure 3a , Figure 3b and Figure 3c shown.

[0088] Attached to the instruction manual Figure 1a , Figure 1b , Figure 1c , Figure 1d , Figure 2a , Figure 2b , Figure 2c , Figure 2d , Figure 3a , Figure 3b , Figure 3c and Figure 3d It can be seen that:

[0089] (1) The continuous rolling method of the dual-phase high-strength steel of the embodiment of the present invention adopts a laser welding technology with a laser power of 6 kW to 8 kW, a welding speed of 6.0 m / min to 6.5 m / min, a wire feeding speed of 5.9 m / min to 6.3 m / min, and an annealing power of 2.23 kW to 3.2 kW. A plurality of original steel coils are welded end to end into a total steel coil, and then pickling and continuous rolling are performed. The cupping and bending tests of the dual-phase high-strength steel obtained by rolling meet the performance requirements.

[0090] (2) By the attached Figure 1a ~Attached Figure 3c It can be obtained that in the continuous rolling method of the dual-phase high-strength steel of the embodiment of the present invention, after laser welding, the parent material structure is ferrite + pearlite + bainite (such as Figure 1a , Figure 2a and Figure 3a The banded structure is 4.5; the heat affected zone is composed of martensite + ferrite + bainite; the weld is composed of martensite + ferrite + bainite (as shown in Figure 1). Figure 1c , Figure 2c and Figure 3c As shown). It can be seen that, by using the continuous rolling method of the dual-phase high-strength steel of the embodiment of the present invention, the dual-phase high-strength steel with excellent metallographic structure can be rolled.

[0091] (3) In the continuous rolling method of the dual-phase high-strength steel of the embodiment of the present invention, the ends of several original steel coils are first laser welded into a large total steel coil, and then pickled and continuously rolled. After the continuous rolling, only the parts with thickness difference at the ends of the total steel coil need to be cut off, thereby avoiding the need to cut off each steel coil after rolling due to the thickness difference at the ends of the strip, thereby reducing the yield rate.

[0092] (4) The continuous rolling method of the dual-phase high-strength steel in the embodiment of the present invention adopts laser welding, and the ends of two adjacent steel coils can be directly welded together without using additional solder, thereby improving the compatibility between the steel coils.

[0093] (5) As attached to the instruction manual Figure 1d , Figure 2d and Figure 3d As shown, in the continuous rolling method of dual-phase high-strength steel in an embodiment of the present invention, the bending angle of the bent steel coil corresponding to the obtained weld meets the requirements.

[0094] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the main purpose of the present invention, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A method for continuous rolling of dual-phase high-strength steel, characterized in that: The steps include: The head and tail of several original steel coils are laser welded to obtain a total steel coil, wherein in the laser welding: the solder is the original steel coil itself, the laser power is 6kW to 8kW, the welding speed is 6.0m / min to 6.5m / min, the wire feeding speed is 5.9m / min to 6.3m / min, and the annealing power is 2.23kW to 3.2kW; The total steel coil is pickled and continuously rolled.

2. The continuous rolling method of dual-phase high-strength steel according to claim 1, characterized in that: The thickness difference between the head and tail of the strip obtained after pickling and continuous rolling is less than 1.1 mm.

3. The continuous rolling method of dual-phase high-strength steel according to claim 2, characterized in that: The width difference between the head and tail of the strip obtained after pickling and continuous rolling is less than 300 mm.

4. The continuous rolling method of dual-phase high-strength steel according to claim 3, characterized in that: The thickness deviation rate of the strip obtained after pickling and continuous rolling is less than 30%.

5. The continuous rolling method of dual-phase high-strength steel according to claim 1, characterized in that: In the laser welding, the laser welding machine selected is the GD-10C-1620 laser welding machine.

6. The continuous rolling method of dual-phase high-strength steel according to claim 3, characterized in that: The number of coils of the original steel coil is more than 2.

7. The continuous rolling method of dual-phase high-strength steel according to any one of claims 1 to 6, characterized in that: The continuous rolling method further comprises the steps of: cutting the steel coil obtained by pickling and continuous rolling into a plurality of rolled steel coils, and then subjecting the steel coils to galvanizing.

8. The continuous rolling method of dual-phase high-strength steel according to any one of claims 1 to 7, characterized in that: The number of coils of the steel coils after pickling and continuous rolling is not less than the number of coils of the original steel coils.

9. A continuous rolling system for implementing the continuous rolling method of dual-phase high-strength steel according to any one of claims 1 to 8, characterized in that: The invention comprises a welding unit for laser welding the ends of two original steel coils and a rolling unit for rolling and welding the total steel coil.

10. Use of the continuous rolling method of dual-phase high-strength steel according to any one of claims 1 to 8 in the field of dual-phase high-strength steel production.

Images