CN116351871A

CN116351871A - Stainless steel composite board with excellent plate shape and preparation method thereof

Info

Publication number: CN116351871A
Application number: CN202310179196.4A
Authority: CN
Inventors: 镇凡; 曲锦波; 邵春娟; 陆春洁; 郑传波; 李小兵
Original assignee: Institute Of Research Of Iron & Steel shagang jiangsu Province; Jiangsu Shagang Group Co Ltd; Zhangjiagang Hongchang Steel Plate Co Ltd; Zhangjiagang Rongsheng Special Steel Co Ltd
Current assignee: Institute Of Research Of Iron & Steel shagang jiangsu Province; Jiangsu Shagang Group Co Ltd; Zhangjiagang Hongchang Steel Plate Co Ltd; Zhangjiagang Rongsheng Special Steel Co Ltd
Priority date: 2023-02-28
Filing date: 2023-02-28
Publication date: 2023-06-30

Abstract

The invention discloses a stainless steel composite board with excellent plate shape and a preparation method thereof. Heating and rolling the obtained composite blank, cooling after rolling, and intermittently cooling the large composite plate in an ultra-fast cooling system: the ultra-fast cooling system is provided with 24 groups of cooling headers arranged along a roller way, the cooling distance of each group of cooling headers is 1M, when the composite board large board passes through the ultra-fast cooling system, the opening and closing states of all 24 groups of cooling headers are controlled in a mode that N groups of cooling headers are opened every time and then M groups of cooling headers are not opened, the cooling water pressure is 0.2MPa, the cooling speed is 3-15 ℃/s, and the final cooling temperature is 380-450 ℃; wherein N takes on the value of 2, 3 or 4, and M takes on the value of 2, 3 or 4.

Description

Stainless steel composite board with excellent plate shape and preparation method thereof

Technical Field

The invention belongs to the technical field of steel material preparation, and relates to a stainless steel composite board with an excellent plate shape and a preparation method thereof.

Background

With the continuous development of science and industry, common alloy or single metal is difficult to meet the requirement of industrial development on the comprehensive performance of materials, and composite boards are generated. The stainless steel composite board takes carbon steel or low alloy steel as a base layer, takes stainless steel as a multi-layer, and realizes metallurgical bonding of a composite interface by methods of explosive cladding, rolling cladding and the like, so that the resources are saved and the cost is reduced on the premise of not reducing the using effect (mechanical strength, corrosion resistance and the like). The stainless steel composite board is widely applied to industries such as petrochemical industry, pressure vessels, power equipment, medical equipment, water conservancy, papermaking, bridges and the like.

The construction of cross-river and cross-sea channels is urgent to construct a large-span steel bridge. Along with the increase of the span of the steel bridge, the requirements on the stainless steel composite board for the bridge structure are also higher and higher, such as large thickness, good shape, excellent combination property, high strength, high toughness and the like.

The existing stainless steel composite board adopts modes of explosive cladding, non-vacuum preparation of composite blanks, vacuum electron beam welding blank making and the like, and has the problems of poor surface quality, difficult control of the plate shape, poor interface bonding quality, low yield, low production efficiency and the like.

Disclosure of Invention

The invention aims to provide a stainless steel composite board with excellent plate shape and a preparation method thereof.

In order to achieve the above object, an embodiment of the present invention provides a method for manufacturing a stainless steel composite plate having an excellent plate shape, which includes three steps of composite blank manufacturing, composite blank rolling, and composite plate separation straightening, which are sequentially performed;

in the preparation step of the composite blank, the chemical components of the base material of the composite blank are as follows in percentage by mass: c:0.03 to 0.16 percent, si:0.11 to 0.29 percent, mn:1.31 to 1.54 percent, P is less than or equal to 0.018 percent, S is less than or equal to 0.0030 percent, cr:0.06 to 0.29 percent, ni is less than or equal to 0.24 percent, cu is less than or equal to 0.24 percent, mo is less than or equal to 0.24 percent, nb: 0.011-0.034%, ti: 0.011-0.019%, al:0.030 to 0.040 percent, and the balance being Fe and unavoidable impurities;

The composite billet rolling step comprises the following steps:

heating the obtained composite blank, wherein the soaking temperature is 1170-1220 ℃, the total heating time is more than or equal to 1.2×tmin/mm, and t is the thickness of the composite blank;

adopting two-stage controlled rolling of rough rolling and finish rolling, and finishing the rough rolling stage when the finishing rolling temperature is more than or equal to 1000 ℃ and the thickness of the intermediate blank is 2.5-3.5 times of the target thickness of the large composite plate in the rough rolling stage; then, when the surface temperature of the intermediate blank is reduced to below 840 ℃, starting a finish rolling stage, wherein the finish rolling temperature of the finish rolling stage is more than or equal to 780 ℃;

after rolling, cooling, and enabling the large composite plate to enter an ultra-fast cooling system for intermittent cooling: the ultra-fast cooling system is provided with 24 groups of cooling headers arranged along a roller way, the cooling distance of each group of cooling headers is 1M, when the composite board large board passes through the ultra-fast cooling system, the opening and closing states of all 24 groups of cooling headers are controlled in a mode that N groups of cooling headers are opened every time and then M groups of cooling headers are not opened, the cooling water pressure is 0.2MPa, the cooling speed is 3-15 ℃/s, and the final cooling temperature is 380-450 ℃; wherein N takes on the value of 2, 3 or 4, and M takes on the value of 2, 3 or 4.

Preferably, the roller way speed of the ultra-rapid cooling system is 0.4-0.9 m/s.

Preferably, in the step of heating the obtained composite blank, five-stage heating including preheating, one heating, two heating, three heating and soaking is adopted, wherein the preheating temperature is less than or equal to 850 ℃, the retention time is (0.45-0.55) tmin/mm, the heating temperature is 1030-1090 ℃, the retention time is (0.35-0.45) t min/mm, the two heating temperatures are 1100-1160 ℃, the retention time is (0.25-0.35) t min/mm, the three heating temperatures are 1140-1180 ℃, the retention time is (0.15-0.25) t min/mm, and the soaking temperature is 1170-1210 ℃, and the retention time is (0.10-0.20) tmin/mm.

Preferably, in the step of adopting two-stage controlled rolling of rough rolling and finish rolling, during the rough rolling stage, longitudinal rolling is adopted in the 1 st pass, and the rolling reduction is more than or equal to 46mm; the 2 nd pass starts to adopt transverse rolling until the n th pass rolls the composite blank to the target width of the final composite plate, and the rolling reduction of the 2 nd pass is more than or equal to 25mm; the n+1th pass starts to adopt longitudinal rolling, and the rough rolling stage is ended when the thickness of the intermediate blank is 2.5-3.5 times of the target thickness of the large composite plate, and the rolling reduction of the n+1th pass is more than or equal to 30mm; in the whole rough rolling stage, the rolling temperature of the 1 st pass is more than or equal to 1060 ℃, the initial rolling temperature of the rest passes is less than or equal to 1050 ℃, and the final rolling temperature is more than or equal to 1000 ℃; after the rough rolling stage is finished, watering and cooling are carried out during the period of finishing the rough rolling stage, and when the surface temperature of the intermediate billet is reduced to below 840 ℃, the finish rolling stage is started, and the initial rolling temperature of the finish rolling stage is 810-840 ℃ and the final rolling temperature is 780-810 ℃.

Preferably, in the step of "heating the obtained composite blank",

heating the obtained composite blank, wherein the soaking temperature is 1200-1220 ℃, the total heating time is more than or equal to 1.2×tmin/mm, t is the thickness of the composite blank, and the heat preservation time of a soaking section is 30-50 min;

the method comprises the steps of adopting two-stage control rolling of rough rolling and finish rolling, wherein in the rough rolling stage, the initial rolling temperature is less than or equal to 1050 ℃, the final rolling temperature is more than or equal to 1000 ℃, transverse rolling is performed firstly, then longitudinal rolling is performed, at least one pass of rolling reduction is more than or equal to 35mm in the longitudinal rolling process, the total rolling reduction of rough rolling is 40-60%, and the rough rolling stage is finished when the thickness of an intermediate blank is 2.5-3.5 times of the target thickness of a large plate of the composite plate; then, when the temperature is kept, watering and cooling are carried out during the period, and when the surface temperature of the intermediate blank is reduced to be lower than 830 ℃, the finish rolling stage is started; the finishing temperature in the finish rolling stage is more than or equal to 800 ℃, and the total rolling reduction of the finish rolling is 55-75%.

Preferably, after intermittent cooling, the cooling bed on the large composite board is naturally cooled to room temperature, and the rolling step of the composite blank is finished so far, and the composite board enters the separation and straightening step of the composite board.

Preferably, after intermittent cooling, the large composite board directly enters a straightener for straightening, a cooling bed on the straightened large composite board is naturally cooled, and when the surface temperature is reduced to below 200 ℃, the cold straightening is carried out by adopting a cold straightener.

Preferably, after intermittent cooling, the large composite board directly enters a straightener for straightening;

placing the straightened composite board large board at the temperature T _f Performing stack cooling between two steel plates at the temperature of +100-150 ℃, wherein the stack cooling time is 0.4min/mm multiplied by 0+/-5 min, and t0 is the thickness of a large composite plate;

naturally cooling the cooling bed on the large composite board to room temperature after the cold stacking is finished;

T _f ＝550+30[Si]-20[Mn]+15[Cr]-15[Ni]+10[Mo]wherein [ Si ]]、[Mn]、[Mo]、[Cr]、

[ Ni ] is 100 times of the mass percentage of each element in the base material.

Preferably, the composite blank preparation step specifically includes:

preparing two carbon steel billets with thickness T1, length L1 and width W1 as a base material for forming a composite board base layer; preparing two stainless steel billets with thickness T2, length L2 and width W2 as composite materials for forming composite layers of the composite plates; l2 is less than L1, W2 is less than W1;

carrying out surface treatment on at least one surface of each of the two base materials and the two composite materials;

coating a release agent on one surface of a composite material;

assembling according to the stacking sequence of the base material, the composite material and the base material; the composite material is placed in the middle relative to the base material, the surfaces of the base material and the composite material, which are contacted with each other, are both surfaces subjected to surface treatment, and the surface of the isolating agent is coated on the other composite material;

Four sealing strips with the width W3 are prepared, the W3 = 2T 2-1-2 mm, the sealing strips are attached to the four sides of two composite materials, gas shielded welding is carried out between the adjacent sealing strips and between the sealing strips and the base materials, so that the two base materials and the sealing strips form a whole, and a composite blank base blank is obtained;

a round hole is processed on the seal at the groove of the side edge of the composite blank base blank, and a seamless steel tube is welded at the round hole;

overlaying the grooves on the four sides of the composite blank base blank;

vacuumizing the composite blank through the seamless steel pipe by adopting a vacuum pump, wherein the vacuum degree is less than or equal to 10 ^-1 Pa, and then maintaining the pressure for more than 4 hours; and finally, sealing the seamless steel tube.

Preferably, the chemical components of the substrate of the composite blank are as follows in mass percent: c:0.03 to 0.07 percent, si:0.11 to 0.19 percent, mn:1.46 to 1.54 percent, P is less than or equal to 0.010 percent, S is less than or equal to 0.0015 percent, cr:0.21 to 0.29 percent, ni:0.16 to 0.24 percent, cu:0.16 to 0.24 percent, mo:0.16 to 0.24 percent, nb:0.026 to 0.034 percent, ti: 0.011-0.019%, al:0.030 to 0.040 percent, and the balance of Fe and unavoidable impurities.

In order to achieve the above object, an embodiment of the present invention provides a stainless steel composite plate having an excellent plate shape, which is manufactured by the manufacturing method.

Preferably, the total thickness of the composite board is more than or equal to 19mm, the thickness of the base layer is more than or equal to 16mm, the thickness of the composite layer is 1-10 mm, the Vickers hardness difference in the thickness direction of the base layer of the composite board is less than or equal to 10, the strength difference in the head and tail is less than or equal to 40MPa, the strength difference in the whole board is less than or equal to 40MPa, and the unevenness is less than or equal to 2mm/m.

Preferably, the yield strength of the composite board is more than or equal to 345MPa, the tensile strength is more than or equal to 490MPa, the elongation after fracture is more than or equal to 18%, and the yield ratio is less than or equal to 0.85; the bonding rate of the composite interface is 100%, and the shearing strength is more than or equal to 300MPa; the impact energy at 0 ℃ is more than or equal to 120J, the impact energy at-20 ℃ is more than or equal to 120J, and the impact energy at-40 ℃ is more than or equal to 120J.

Preferably, the yield strength of the composite board is more than or equal to 500MPa, the tensile strength is more than or equal to 630MPa, the elongation after fracture is more than or equal to 18%, and the yield ratio is less than or equal to 0.86; the impact energy at 0 ℃ is more than or equal to 240J, the impact energy at-20 ℃ is more than or equal to 200J, and the impact energy at-40 ℃ is more than or equal to 150J.

Compared with the prior art, the invention has the beneficial effects that: on one hand, in the whole preparation method, the corrosion resistance and the mechanical strength of the stainless steel composite plate are ensured through the specific control of the process, and the corrosion resistance and the mechanical property are prevented from being deteriorated in the rolling process of the composite blank; on the other hand, the problems of difficult plate shape control, poor surface quality, low production efficiency and the like of the existing stainless steel composite plate thick plate are solved, and the construction requirements of steel bridge projects are met; on the other hand, the yield is high in the production process, and the production efficiency is high.

Drawings

In the various illustrations of the invention, certain dimensions of structures or portions are exaggerated relative to other structures or portions for clarity of illustration and description, and thus serve only to illustrate the basic structure of the inventive subject matter.

FIG. 1 is a schematic cross-sectional view of a steel blank according to the present invention;

FIG. 2 is a schematic cross-sectional view of a composite blank corresponding to FIG. 1;

FIG. 3 is a schematic cross-sectional view of two single-sided stainless steel composite panels rolled from the composite blank of FIG. 2;

FIG. 4a is a schematic flow diagram of a first embodiment of the composite bloom rolling step of the present invention;

FIG. 4b is a schematic flow diagram of a second embodiment of the composite bloom rolling step of the present invention;

FIG. 4c is a schematic flow diagram of a third embodiment of the composite bloom rolling step of the present invention;

FIG. 4d is a schematic flow chart of a fifth embodiment of the composite bloom rolling step of the present invention;

FIG. 4e is a schematic flow chart of a fourth embodiment of the composite bloom rolling step of the present invention;

fig. 4f is a schematic flow chart of a sixth embodiment of the composite bloom rolling step of the present invention.

Detailed Description

The invention provides a preparation method of a single-sided stainless steel composite board with an excellent plate shape and a composite board prepared based on the method. Specifically, the preparation method comprises three general steps of composite blank preparation, composite blank rolling and composite plate separation and straightening.

The total steps of the preparation of the composite blank comprise the following sub-steps:

preparing two carbon steel billets with thickness T1, length L1 and width W1 as base materials; preparing two stainless steel billets with thickness T2, length L2 and width W2 as composite materials;

coating a release agent on one surface of a composite material;

assembling according to the stacking sequence of the base material, the composite material and the base material;

overlaying the grooves on the four sides of the composite blank base blank;

Further, the above sub-steps are described in detail as follows.

Step "preparing two carbon steel billets with length L1 and width W1 as base materials; and preparing two stainless steel billets with the length L2 and the width W2 as composite materials ", namely a billet preparation step.

Wherein, the thickness T1, the length L1 and the width W1 of the carbon steel billet serving as the base material are rectangular billets; similarly, the stainless steel billet as the composite material is also rectangular in thickness T2, length L2, and width W2.

And L2 is smaller than L1, W2 is smaller than W1, and the length and width dimensions of the composite material are smaller than those of the base material. Preferably, l2=l1-L0, w2=w1-W0, and the preferred value ranges of L0 and W0 are 90 to 150mm, respectively.

As a preferable scheme, the surface oxide skin pressing depth and the surface pit depth of the carbon steel billet are less than or equal to 0.3mm, and the unevenness is less than or equal to 3mm/m; the stainless steel billet has no scratch on the surface and the unevenness is less than or equal to 2mm/m. Thus, the steel billet is prevented from entering the production line of the composite board with obvious surface defects or plate defects.

Next, as for the step "surface-treating at least one surface of each of the two base materials and the two composite materials", that is, a blank surface-treating step.

In this embodiment, one surface of each base material and each composite material is polished to remove surface oxide scale and expose metallic luster. Referring to fig. 1, for example, polishing is performed on the surface p1a of the base material 11a by using a grinder, belt sander or milling machine to remove surface oxide skin and expose metallic luster; similarly, polishing is performed on the surface p2a of the prepared base material 12a by using a grinder, belt sander or milling machine to remove surface scale and expose metallic luster.

Grinding and polishing the surface p3a of the prepared composite material 21a by adopting a wire wheel to remove surface oxide skin and expose metallic luster; similarly, the surface p4a of the prepared composite material 22a is polished with a wire wheel to remove surface scale and expose metallic luster.

As will be seen later, when assembling, the surface treated (polished in this embodiment) is used as a surface where the base material and the composite material contact each other, for example, the surface p1a and the surface p3a contact each other, and the surface p4a and the surface p2a contact each other, whereby the interface bonding quality can be ensured.

The description of the other sub-steps of the composite blank preparation step is continued below.

The step of "painting a release agent on one surface of a piece of composite material", that is, the step of painting a release agent.

In the previous blank surface treatment step, the surface of the composite material, which is in contact with the base material during assembly, is subjected to surface treatment such as polishing, so as to ensure the interface bonding quality of the composite board; the purpose of the step of brushing the release agent is to avoid the release agent, so that the composite material and the surface contacted when the composite material are assembled are combined in the rolling step of the composite blank, and finally are difficult to separate.

Based on this, a release agent is optionally applied to one of the two composites. If the selected composite material is surface treated in the previous blank surface treatment step and the other is not surface treated, the release agent is applied to the surface which is not surface treated in the release agent application step. If, as mentioned above, both surfaces of the selected composite are surface treated in the previous blank surface treatment step, then in the release agent application step, the release agent is applied to the surface intended to be faced with the other composite at the time of assembly.

For example, taking fig. 1 as an example, a release agent may be applied to the surface p6a of the composite 22a or the surface p5a of the composite 21 a.

With respect to the release agent, two preferred embodiments are provided herein, each of which is described below.

< first embodiment of the Release agent >

In this embodiment, the release agent is a coating solution containing silicon oxide and magnesium oxide, wherein the mass ratio of silicon oxide to magnesium oxide is 3:1. The isolating agent of the embodiment can achieve good isolating effect and ensure the subsequent separation of two composite board small plates.

When the release agent is adopted to paint the surface of the composite material, the amount of the paint release agent is 20ymg/m ² That is, the weight of the release agent per unit area of the surface of the composite material was 20ymg. Wherein y is the ratio of the thickness of the composite billet produced in the composite billet preparation step to the thickness of the composite plate large plate formed by subsequent rolling, and the ratio is also called a composite billet rolling compression ratio.

Further, according to the present embodiment, after finishing the application of the release agent and before the subsequent assembly, the composite material coated with the release agent is placed in a bogie hearth furnace to be heated and dried, the drying temperature is 340-360 ℃, and the drying time is 35-45 min.

< second embodiment of Release agent >

In this embodiment, the components of the release agent are as follows by weight: 25-35% of silicon nitride, 5-10% of thermosetting amino resin and 55-70% of water. Compared with the existing isolating agent and even compared with the first embodiment of the isolating agent, the isolating agent of the embodiment not only can achieve good isolating effect and ensure the subsequent separation of two composite board small plates, but also has strong chemical stability, high temperature resistance and thermal shock resistance of the active ingredient silicon nitride, and the thermosetting amino resin serving as the binder can be cured at low temperature, has no toxicity and can achieve stronger bonding effect with little consumption, thus the isolating agent is low in cost as a whole, simple to operate and good in isolating and attaching effects.

Here, there is provided a preferred preparation method of the release agent, comprising: firstly, placing 5-10% of silicon nitride (in percentage by weight) into a container such as a beaker, and then pouring 15-25% of water for stirring; after the silicon nitride has no granular feel and no bubble, pouring 2-3% of thermosetting amino resin, and continuing stirring; when the mixture is in a viscous state, continuously pouring the residual silicon nitride and water, stirring for 3-5 min, and pouring the residual thermosetting amino resin; and (5) stirring to be sticky, and preparing the release agent.

When the release agent is adopted to paint the surface of the composite material, the thickness of the paint release agent is 0.2-0.5 mm.

Further, according to the present embodiment, after finishing the application of the release agent and before the subsequent assembly, the composite material coated with the release agent is heated and dried at 100 to 250 ℃ for 20 to 40 minutes.

Next, after the step of applying the release agent, the step of "assembling in the order of stacking the base material, the composite material, and the base material" will be described.

The step of assembling is carried out according to the stacking sequence of the base material, the composite material and the base material, namely the assembling step. Wherein, in addition to the stacking sequence of the base material, the composite material and the base material, the following needs to be satisfied:

1) The surfaces of the base material and the composite material which are contacted with each other are the surfaces subjected to the surface treatment; for example, referring to fig. 2, the surface p2a of the base material 12a and the surface p4a of the composite material 22a are in contact with each other, and the surface p1a of the base material 11a and the surface p3a of the composite material 21a are in contact with each other;

2) The surface coated with the release agent faces the other composite material; for example, referring to fig. 2, one of the surface p6a and the surface p5a is coated with a release agent 30a;

3) The composite material is placed in the middle relative to the base material; in view of the above, only a group of base materials and composite materials in the composite blank are described as an example in which, in the assembled state, the distance from the lateral side of the composite material 21a (corresponding to the long side of the surface p3 a) to the lateral side of the base material 11a (corresponding to the long side of the surface p1 a) is half of W0, and the distance from the lateral side of the composite material 21a (corresponding to the short side of the surface p3 a) to the lateral side of the base material 11a (corresponding to the short side of the surface p1 a) is half of L0, as described above, L0 and W0 are respectively 90 to 150mm, that is, the distance from the lateral side of the composite material 21a to the lateral side of the base material 11a is 45 to 75mm, in view of the composite blank being arranged substantially vertically symmetrically.

In the above description of the assembling step, in a preferred embodiment, after the assembling step is performed, the stacked four billets are integrally placed under a four-column hydraulic machine, and the opposite surfaces of the two base materials (i.e., the upper surface of the upper base material and the lower surface of the lower base material) are pressurized, where the pressure is not less than 500 tons. Thus, contact between adjacent billets can be made tighter.

Further, in the step of preparing four seals with the width W3, the seals are attached to four sides of two composite materials, and gas shielded welding is carried out between the adjacent seals and between the seals and the base materials, so that two base materials and the seals form a whole to obtain a composite blank base blank, and the four stacked steel blanks form a whole to be connected into the composite blank base blank based on the arrangement of the seals. Specifically, referring to fig. 2, the composite green body is: the two

base materials

11a and 12a form upper and lower surfaces, the two

composite materials

21a and 22a are positioned in the middle, four seals 40a are arranged around the two

composite materials

21a and 22a in a four-sided frame, and the two

base materials

11a and 12a are connected.

The width W3=2T2-1-2 mm of the seal, namely the width of the seal is slightly smaller than the sum of the thicknesses of the two composite materials by 1-2 mm. The upper and lower composite materials are wrapped by the seal with the width, so that the wrapping effect is improved.

In the four seals, two seals are respectively attached to two lateral side edges of two composite materials, and the length L31=L2-1-2 mm; the other two seals are respectively attached to two longitudinal side edges of the two composite materials, and the length L32=W2-1-2 mm.

Preferably, the thickness T3 of the seal is 12-15 mm.

The forming mode of each seal strip can be directly cut on a steel plate according to the thickness T3, the width W3 and the length L31 or L32 without welding, or can be formed by splicing a plurality of seal strips with different lengths through welding.

In the step, before gas shielded welding is performed between adjacent seals and between the seals and the base material, both ends and both sides of each seal can be polished to remove surface oxide skin, so as to improve welding effect; and/or grooves can be formed at two ends and two sides of each seal.

Further, as a preferred embodiment, in the step of performing gas shielded welding between adjacent seals and between the seal and the substrate, the welding speed is 300-360 mm/min, and the temperature between the seal and the substrate is controlled to be 135-165 ℃ in the welding process.

Next, for the step of processing a round hole on the seal at the groove on the side edge of the composite blank base blank, and welding a seamless steel tube at the round hole, wherein the groove is formed between two base materials and outside the seal; in this step, a round hole is machined to weld the seamless steel pipe so as to facilitate the subsequent evacuation of the interior of the composite blank.

As a preferred mode, the round hole is formed in the middle of the short side (i.e., the side in the longitudinal direction) of the composite green body, but is not limited thereto.

As a preferable mode, the diameter of the round hole is 8-12 mm; correspondingly, the outer diameter of the seamless steel pipe is consistent with the diameter of the round hole, the wall thickness is 1.2-2 mm, and the length is 200-400 mm.

And then, carrying out overlaying welding on grooves on four sides of the composite blank base blank in the step, and specifically adopting submerged arc overlaying welding. It will be appreciated that, outside the four-sided frame formed by the seal, a filling layer 50a in the shape of a four-sided frame is formed by butt welding in this step, see fig. 2.

As a preferred mode, before welding, the welding flux is baked for 2 hours at 350 ℃ and then is kept at 150 ℃ for 1 hour; in the welding process, the temperature between the control channels is 135-165 ℃, and the welding speed is 420-480 mm/min. Therefore, the submerged arc surfacing technology combines the sealing strip wrapping and gas shielded welding to jointly realize the stable connection of four billets, ensures the connection strength, avoids cracking abnormality in the subsequent composite billet rolling step, and further can further improve the interface bonding effect on the basis of realizing the quality advantage of the composite plate.

In addition, in the welding process, before each welding construction, welding bead attachments need to be cleaned, and welding beads are kept clean; and after welding, covering with heat-insulating cotton to insulate heat.

Next, the step of "vacuum pumping the composite blank through the seamless steel pipe by using a vacuum pump, the vacuum degree

≤10 ^-1 Pa, and then maintaining the pressure for more than 4 hours; finally, in the sealing treatment of the seamless steel tube, the air suction port of the vacuum pump is abutted with the seamless steel tube, and the seamless steel tube is communicated with the space inside the composite blank (such as the surface gap between the composite material and the base material, the surface gap between the composite material and the composite material, the surface gap between the composite material and the seal, and the like) so as to discharge the air in the space until the vacuum degree is less than or equal to 10 ^-1 Pa, and the vacuum degree can be ensured by maintaining the pressure for more than 4 hours. Therefore, air in the space can be avoided, and surface oxidation at the composite interface is caused in the subsequent rolling of the composite blank, so that the bonding quality of the composite interface is ensured.

Further, in this step, the seamless steel pipe is subjected to a sealing treatment, which can be performed in a manner that is currently available in the steel field, for example, by heating the seamless steel pipe with a flame gun and flattening the pipe to effect sealing.

The general steps of preparing the composite blank are described in detail, wherein the specific settings of surface treatment, vacuumizing, welding, sealing and the like lay a foundation for obtaining excellent interface bonding quality and surface quality of the subsequent composite blank in subsequent rolling; and the release agent is arranged, so that the smooth separation of the two composite small plates is facilitated.

As described above, the manufacturing method of the present invention further includes a total step of rolling the composite billet after the total step of manufacturing the composite billet. The invention provides four embodiments of the composite billet rolling step, and the following details are respectively presented.

< first embodiment of composite Rolling step >

In this embodiment, referring to fig. 4a, the clad-blank rolling step comprises the following sub-steps:

the method comprises the steps of adopting two-stage control rolling of rough rolling and finish rolling, wherein in the rough rolling stage, the initial rolling temperature is less than or equal to 1050 ℃, the final rolling temperature is more than or equal to 1000 ℃, transverse rolling is performed firstly, then longitudinal rolling is performed, at least one pass of rolling reduction is more than or equal to 35mm in the longitudinal rolling process, the total rolling reduction of rough rolling is 40-60%, and the rough rolling stage is finished when the thickness of an intermediate blank is 2.5-3.5 times of the target thickness of a large plate of the composite plate; then, when the temperature is kept, watering and cooling are carried out during the period, and when the surface temperature of the intermediate blank is reduced to be lower than 830 ℃, the finish rolling stage is started; the finishing temperature in the finish rolling stage is more than or equal to 800 ℃, and the total rolling reduction of the finish rolling is 55-75%;

after rolling, cooling, and enabling the large composite plate to enter an ultra-fast cooling system for intermittent cooling: the ultra-fast cooling system is provided with 24 groups of cooling headers arranged along a roller way, the cooling distance of each group of cooling headers is 1M, when the composite board passes through the ultra-fast cooling system, the opening and closing states of all 24 groups of cooling headers are controlled in a mode that N groups of cooling headers are opened every time and then M groups of cooling headers are not opened, the cooling water pressure is 0.2MPa, the cooling speed is 3-15 ℃/s, the final cooling temperature is 380-450 ℃, and the roller way speed of the ultra-fast cooling system is 0.4-0.9M/s, preferably 0.4-0.6M/s; wherein N takes the value of 2, 3 or 4, M takes the value of 2, 3 or 4; for example, when the composite board passes through the ultra-fast cooling system, the composite board is controlled in a way that 4 groups of cooling headers are opened every time and then 3 groups of cooling headers are not opened, namely, the cooling headers of the 1 st to 4 th groups are opened, the cooling headers of the 5 th to 7 th groups are not opened, the cooling headers of the 8 th to 11 th groups are opened, the cooling headers of the 12 th to 14 th groups are not opened, the cooling headers of the 15 th to 18 th groups are opened, the cooling headers of the 19 th to 21 th groups are not opened, and the cooling headers of the 22 nd to 24 th groups are opened;

And after the large composite board leaves the ultra-rapid cooling system, naturally cooling the cooling bed on the large composite board to room temperature, and finishing the rolling of the composite blank in the step 2) so as to enter the step 3) of separating and straightening of the composite board.

Compared with the prior art, when the large composite plate passes through the ultra-rapid cooling system by adopting the intermittent cooling mode, the large composite plate runs in the cooling header which is alternately opened and the cooling header which is not opened, so that each part of the large composite plate can be cooled, reddened, cooled and reddened … … to be circulated until the large composite plate leaves the ultra-rapid cooling system. In the cooling-reddening cycle of the composite board large board, the carbon steel substrate continuously generates phase change and self-tempering effects, and the phase change reaction gradually permeates into the core until the whole carbon steel substrate is subjected to phase change. The intermittent cooling process is different from the conventional reciprocating cooling, and the reciprocating cooling has the advantages that the temperature difference or the cooling speed difference between the surface layer and the core is larger, the difference between the tissue and the mechanical property is also larger after the surface layer or the near surface layer has completed the phase change, the intermittent cooling process in the embodiment is that the composite board big board has some parts in a cooling state and some parts in the state of the reversion/self tempering at the same time, and each part of the composite board is alternately cooled and the reversion/self tempered along with time, so that the difference of the temperature, the cooling speed, the tissue, the performance and the like of the big board on the surface layer and the core is smaller, for example, the Vickers hardness difference in the thickness direction of the base layer of the finally obtained composite board is less than or equal to 10, the strength difference between the head and the tail is less than or equal to 40MPa, and the strength difference between the whole board is less than or equal to 40MPa. Furthermore, the plate shape of the composite plate can be further improved by intermittent cooling, that is, the unevenness is low, and even if the composite plate is cooled directly by a cooling bed without straightening after the cooling is finished, the excellent plate shape can be obtained.

< second embodiment of composite Rolling step >

In this embodiment, referring to fig. 4b, the clad-blank rolling step comprises the following sub-steps:

five-stage heating of preheating, one heating, two heating, three heating and soaking is adopted, the preheating temperature is less than or equal to 850 ℃, the staying time is (0.45-0.55) t min/mm, the one heating temperature is 1030-1090 ℃, the staying time is (0.35-0.45) t min/mm, the two heating temperature is 1100-1160 ℃, the staying time is (0.25-0.35) t min/mm, the three heating temperature is 1140-1180 ℃, the staying time is (0.15-0.25) t min/mm, and the soaking temperature is 1170-1210 ℃, and the staying time is (0.10-0.20) t min/mm;

the two-stage control rolling of rough rolling and finish rolling is adopted, and in the rough rolling stage, longitudinal rolling is adopted in the 1 st pass, and the rolling reduction is more than or equal to 46mm; the 2 nd pass starts to adopt transverse rolling until the n th pass rolls the composite blank to the target width of the final composite plate, and the rolling reduction of the 2 nd pass is more than or equal to 25mm; the n+1th pass starts to adopt longitudinal rolling, and the rough rolling stage is ended when the thickness of the intermediate blank is 2.5-3.5 times of the target thickness of the large composite plate, and the rolling reduction of the n+1th pass is more than or equal to 30mm; in the whole rough rolling stage, the rolling temperature of the 1 st pass is more than or equal to 1060 ℃, the initial rolling temperature of the rest passes is less than or equal to 1050 ℃, and the final rolling temperature is more than or equal to 1000 ℃; after finishing the rough rolling stage, cooling by watering during the period, and starting a finish rolling stage when the surface temperature of the intermediate billet is reduced to below 840 ℃, wherein the initial rolling temperature of the finish rolling stage is 810-840 ℃ and the final rolling temperature is 780-810 ℃;

After rolling, cooling, and enabling the large composite plate to enter an ultra-fast cooling system for intermittent cooling: the ultra-fast cooling system is provided with 24 groups of cooling headers arranged along a roller way, the cooling distance of each group of cooling headers is 1M, when a composite board passes through the ultra-fast cooling system, the opening and closing states of all 24 groups of cooling headers are controlled in a mode that N groups of cooling headers are opened every time and then M groups of cooling headers are not opened, the cooling water pressure is 0.2MPa, the cooling speed is 3-15 ℃/s, the final cooling temperature is 380-450 ℃, and the roller way speed of the ultra-fast cooling system is 0.4-0.9M/s; wherein N takes the value of 2, 3 or 4, M takes the value of 2, 3 or 4;

That is, this embodiment differs from the first embodiment of the above-described composite-billet rolling step in two steps of heating and rolling.

Compared with the prior art, the method also adopts intermittent cooling, and has the beneficial effects brought by the intermittent cooling process, and can be referred to the description of the first embodiment of the rolling step of the composite blank. Further, compared with the prior art, the heating procedure of the embodiment can better control the heating rate of the composite blank in each section, ensure the blank to be heated uniformly, avoid cracking and air leakage of the composite blank caused by the difference of the thermal properties of the base material and the composite material of the composite blank, and further ensure the interface bonding effect. Moreover, the rolling process of the embodiment adopts the modes of longitudinal rolling, transverse rolling and longitudinal rolling, so that the realization of rolling under high pressure can be ensured, the core of the composite blank can be effectively permeated, the deformation of the core is promoted, and the combination rate of a composite interface is ensured; when the temperature is reached, an instant cooling device is adopted for cooling, so that the temperature reaching time is reduced, the rolling efficiency is improved, and meanwhile, the overlength of the temperature reaching time is avoided, and the crystal grains of the carbon steel base material grow; and the temperature control in the finish rolling stage can refine grains and ensure that the thick plate of the composite plate has good low-temperature impact toughness.

< third embodiment of composite Rolling step >

This embodiment is identical to the first embodiment of the composite-blank rolling step described above in terms of steps such as heating, two-stage controlled rolling, cooling, and the like, and differs only in that: the step after the composite board large board leaves the ultra-rapid cooling system.

In the first implementation mode of the composite blank rolling step, after the composite plate large plate leaves the ultra-rapid cooling system, the cooling bed on the composite plate large plate is naturally cooled to room temperature; in contrast, in the present embodiment, referring to fig. 4c, after the composite board big board leaves the ultra-fast cooling system, the composite board big board directly enters the straightening machine to be straightened, the cooling bed on the straightened composite board big board is naturally cooled, and when the surface temperature is reduced to below 200 ℃, the cold straightening machine is adopted to perform cold straightening. This can further promote the plate shape.

Similarly, the second embodiment of the rolling step of the composite blank may be changed to a fifth embodiment of the rolling step of the composite blank by directly introducing the composite plate into a straightener for straightening after the composite plate leaves the ultra-fast cooling system, naturally cooling the straightened composite plate on a cooling bed, and cold straightening by using a cold straightener when the surface temperature is reduced to below 200 ℃, as shown in fig. 4d.

< fourth embodiment of composite Rolling step >

In the first implementation mode of the composite blank rolling step, after the composite plate large plate leaves the ultra-rapid cooling system, the cooling bed on the composite plate large plate is naturally cooled to room temperature; in contrast, in the present embodiment, after leaving the ultra-rapid cooling system, the composite plate is directly fed into the leveler to be leveled 1 to 3 times, unlike the first embodiment of the composite slab rolling step described above, in the present embodiment, referring to fig. 4e, after which the composite plate is placed at a temperature T _f The stack cooling is carried out between two steel plates with the temperature of +100 ℃ to 150 ℃, the stack cooling time is 0.4min/mm multiplied by 0+/-5 min, and t0 is the thickness of the large composite plate, so that the large composite plate can be slowly cooled in the stack cooling time and can be clamped by the steel plates to maintain the uniformity of the temperature of the heart surface; and after the cooling is finished, naturally cooling the cooling bed on the large composite board. Wherein,,

T _f ＝550+30[Si]-20[Mn]+15[Cr]-15[Ni]+10[Mo]Wherein [ Si ]]、[Mn]、[Mo]、[Cr]、[Ni]Is 100 times of the mass percent of each element in the base material. The preferred embodiment, particularly the temperature and the time of the two steel plates in the stack cooling, can further improve the structure, performance and shape of the finally obtained composite plate relative to the first embodiment.

Similarly, the second embodiment of the composite slab rolling step may be modified to a sixth embodiment of the composite slab rolling step by directly straightening the composite slab after the composite slab leaves the ultra-rapid cooling system, performing stack cooling as described above, and naturally cooling the cooling bed on the composite slab after the stack cooling is completed, as shown in fig. 4f.

The total step of rolling the composite blank is described in detail above, and the preparation method of the invention further comprises the total step of separating and straightening the composite plate as described above. Specifically, the total step of separating and straightening the composite board comprises the following sub-steps:

for the large composite board obtained in the previous composite blank rolling total step, a plasma cutting machine is adopted to cut four sides of the large composite board to remove parts outside sealing strips, and the large composite board is separated into an upper composite board small board and a lower composite board small board;

And (5) transversely flattening and cold straightening the small plates of the composite plate to obtain a stainless steel composite plate finished product.

Wherein, regarding the part other than the seal in the step of cutting the four sides thereof to remove the part other than the seal, namely, the edge part on the large plate of the composite plate converted from the seal and the filling layer in the composite blank mentioned above after the previous rolling step of the composite blank. Thus, the part is removed to expose the stainless steel cladding, and the large composite plate is separated into an upper composite plate small plate and a lower composite plate small plate without the connecting function of the part. Referring to fig. 3, corresponding to the five embodiments of the blank surface treatment steps described previously, fig. 3 shows the cross-sectional shape of the corresponding two composite panel platelets (i.e., the final single-sided stainless steel composite panel), respectively.

Each composite board small plate is composed of a composite layer and a base layer, wherein the composite layer is obtained by rolling an original composite material, the base layer is obtained by rolling an original base material, and in view of the fact, in fig. 3, the composite layer is still marked with the original composite material label, and the base layer is also marked with the original base material label.

Further, the single-sided stainless steel composite board prepared by the preparation method disclosed by the invention.

The composite layer is preferably austenitic stainless steel, and comprises the following chemical components in percentage by mass: c is less than or equal to 0.15%, si is less than or equal to 1.00%, mn is less than or equal to 2.00%, P is less than or equal to 0.045%, S is less than or equal to 0.030%, ni:6.0 to 22.0 percent, cr:16.0 to 26.0 percent, mo is less than or equal to 3.0 percent, and the balance is Fe and unavoidable impurities. By adopting the chemical composition, the performance of the composite board, especially the corrosion resistance of the composite layer, can be further ensured under the condition of the technical effect, for example, the composite layer is boiled for 20 hours in sulfuric acid-copper sulfate solution, and no intergranular corrosion crack exists after 180 DEG bending.

The base layer is carbon steel, and comprises the following chemical components in percentage by mass: c:0.03 to 0.16 percent, si:0.11 to 0.29 percent, mn:1.31 to 1.54 percent, P is less than or equal to 0.018 percent, S is less than or equal to 0.0030 percent, cr:0.06 to 0.29 percent, ni is less than or equal to 0.24 percent, cu is less than or equal to 0.24 percent, mo is less than or equal to 0.24 percent, nb: 0.011-0.034%, ti: 0.011-0.019%, al:0.030 to 0.040 percent, and the balance being Fe and unavoidable impurities.

Preferably, the chemical components of the base layer are as follows in mass percent: c:0.03 to 0.07 percent, si:0.11 to 0.19 percent, mn:1.46 to 1.54 percent, P is less than or equal to 0.010 percent, S is less than or equal to 0.0015 percent, cr:0.21 to 0.29 percent, ni:0.16 to 0.24 percent, cu:0.16 to 0.24 percent, mo:0.16 to 0.24 percent, nb:0.026 to 0.034 percent, ti: 0.011-0.019%, al:0.030 to 0.040 percent, and the balance of Fe and unavoidable impurities. By adopting the chemical components and combining the control of each temperature, time, rolling reduction and cooling speed in the rolling step of the composite blank, the mechanical property of the composite plate can be further improved and the toughness can be ensured under the condition of the technical effects.

Further, the structure of the base layer of the composite board is a bainite and small amount of ferrite structure, the composite board is excellent in mechanical property, strong in impact toughness and excellent in corrosion resistance, and has good interface bonding quality, plate shape and surface quality, and in addition, the uniformity is high.

Specifically, the total thickness of the composite board is more than or equal to 19mm, the thickness of the base layer is more than or equal to 16mm, and the thickness of the composite layer is 1-10 mm.

The unevenness of the composite board is less than or equal to 3mm/m, even less than or equal to 2mm/m.

The yield strength of the composite board is more than or equal to 345MPa, the tensile strength is more than or equal to 490MPa, the elongation after breaking is more than or equal to 18%, and the yield ratio is less than or equal to 0.85. Even further, the yield strength of the composite board is more than or equal to 500MPa, and the tensile strength is more than or equal to 630MPa.

The bonding rate of the composite interface of the composite board is 100%, and the shearing strength is more than or equal to 300MPa; the impact energy at 0 ℃ is more than or equal to 120J, the impact energy at-20 ℃ is more than or equal to 120J, and the impact energy at-40 ℃ is more than or equal to 120J. Even further, the impact energy of the composite board at 0 ℃ is more than or equal to 240J, the impact energy of the composite board at-20 ℃ is more than or equal to 200J, and the impact energy of the composite board at-40 ℃ is more than or equal to 150J.

The Vickers hardness difference of the base layer of the composite board in the thickness direction is less than or equal to 10, the strength difference between the head and the tail is less than or equal to 40MPa, and the strength difference of the whole board is less than or equal to 40MPa.

In addition, the composite board is bent outwards by 180 degrees and has no cracks, and is bent inwards by 180 degrees and has no cracks. In the corrosion resistance test, the composite layer is sensitized for 2 hours at 650 ℃, then is boiled in sulfuric acid-copper sulfate solution for 20 hours, and is bent by 180 degrees of cold bending, so that no intergranular corrosion cracks exist.

In summary, compared with the prior art, the present invention has the following aspects: in the whole preparation method, the corrosion resistance and the mechanical strength of the stainless steel composite plate are ensured through the specific control of the process, and the corrosion resistance and the mechanical property are prevented from being deteriorated in the rolling process of the composite blank; on the other hand, the problems of difficult plate shape control, poor surface quality, low production efficiency and the like of the existing stainless steel composite plate thick plate are solved, and the construction requirements of steel bridge projects are met; on the other hand, the yield is high in the production process, and the production efficiency is high.

The above detailed description is merely illustrative of possible embodiments of the present invention, which should not be construed as limiting the scope of the invention, and all equivalent embodiments or modifications that do not depart from the spirit of the invention are intended to be included in the scope of the invention.

The advantages of the invention will be further illustrated by the following examples, which are, of course, only some, but not all of the many variations encompassed by the invention.

In the examples, Q500Q steel grade is selected as a base material, and the chemical components of the base material are as follows in percentage by mass: c:0.06%, si:0.17%, mn:1.52%, P:0.010%, S:0.0014%, cr:0.24%, ni:0.21%, cu:0.22%, mo:0.19%, nb:0.031%, ti:0.016%, al:0.037%; the 316L stainless steel is selected as a composite material, and the chemical components of the composite material are as follows in percentage by mass: c:0.020%, si:0.52%, mn:1.36%, P:0.033%, S:0.003%, ni:10.20%, mo:2.10%, cr:16.20%.

Here, each example was prepared according to the embodiment provided by the present invention to prepare a composite blank having a thickness of 322mm and a constant thickness of the substrate. According to the provided implementation mode of the invention, the composite blank is rolled into a composite board big board with the thickness of 46mm, and the composite board big board is implemented according to the step of separating and straightening the composite board in the invention, so that a single-sided stainless steel composite board finished product with the total thickness of 23mm, the base layer thickness of 20mm and the multi-layer thickness of 3mm is obtained.

The rolling steps of the composite blank adopted in each embodiment are as follows: the first embodiment of the clad-rolling step shown in fig. 4a is used in example 1, the fourth embodiment of the clad-rolling step shown in fig. 4e is used in example 2, the third embodiment of the clad-rolling step shown in fig. 4c is used in example 3, the second embodiment of the clad-rolling step shown in fig. 4b is used in example 4, the sixth embodiment of the clad-rolling step shown in fig. 4f is used in example 5, and the fifth embodiment of the clad-rolling step shown in fig. 4d is used in example 6.

Further, the composite board of each example was sampled and tested, the interfacial bonding ratio of each example was 100%, the inward bend was 180 ° acceptable (no crack), the outward bend was 180 ° acceptable (no crack), and after boiling in sulfuric acid-copper sulfate solution for 20h, the composite layer was free of intergranular corrosion cracking after 180 ° bending. In addition, other performance test results are shown in tables 1 and 2.

TABLE 1

TABLE 2

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Claims

1. The preparation method of the stainless steel composite board with excellent plate shape is characterized by comprising three steps of composite board preparation, composite board rolling and composite board separation and straightening which are sequentially carried out;

the composite billet rolling step comprises the following steps:

2. The method for manufacturing a stainless steel composite plate having an excellent plate shape according to claim 1, wherein the roller speed of the ultra-rapid cooling system is 0.4 to 0.9m/s.

3. The method for manufacturing a stainless steel composite plate with excellent plate shape according to claim 1, wherein in the step of heating the obtained composite plate blank, five-stage heating including preheating, one heating, two heating, three heating and soaking is adopted, wherein the preheating temperature is less than or equal to 850 ℃, the retention time is (0.45-0.55) tmin/mm, the heating temperature is 1030-1090 ℃, the retention time is (0.35-0.45) t min/mm, the two heating temperatures are 1100-1160 ℃, the retention time is (0.25-0.35) t min/mm, the three heating temperatures are 1140-1180 ℃, the retention time is (0.15-0.25) t min/mm, and the soaking temperature is 1170-1210 ℃, and the retention time is (0.10-0.20) tmin/mm.

4. The method for producing a stainless steel composite sheet having an excellent sheet shape according to claim 3, wherein in the step of "two-stage controlled rolling using rough rolling+finish rolling", the 1 st pass uses longitudinal rolling in the rough rolling stage, and the rolling reduction is not less than 46mm; the 2 nd pass starts to adopt transverse rolling until the n th pass rolls the composite blank to the target width of the final composite plate, and the rolling reduction of the 2 nd pass is more than or equal to 25mm; the n+1th pass starts to adopt longitudinal rolling, and the rough rolling stage is ended when the thickness of the intermediate blank is 2.5-3.5 times of the target thickness of the large composite plate, and the rolling reduction of the n+1th pass is more than or equal to 30mm; in the whole rough rolling stage, the rolling temperature of the 1 st pass is more than or equal to 1060 ℃, the initial rolling temperature of the rest passes is less than or equal to 1050 ℃, and the final rolling temperature is more than or equal to 1000 ℃; after the rough rolling stage is finished, watering and cooling are carried out during the period of finishing the rough rolling stage, and when the surface temperature of the intermediate billet is reduced to below 840 ℃, the finish rolling stage is started, and the initial rolling temperature of the finish rolling stage is 810-840 ℃ and the final rolling temperature is 780-810 ℃.

5. The method for producing a stainless steel composite sheet having excellent sheet shape according to claim 1, wherein in the step of heating the obtained composite blank,

6. The method for manufacturing a stainless steel composite plate having an excellent plate shape according to claim 1, wherein after the intermittent cooling, the cooling bed on the large plate of the composite plate is naturally cooled to room temperature, and the composite plate separating and straightening step is performed after the rolling step of the composite plate blank is completed.

7. The method for manufacturing a stainless steel composite plate with excellent plate shape according to claim 1, wherein after intermittent cooling, the composite plate big plate directly enters a straightener for straightening, the straightened composite plate big plate is cooled naturally by a cooling bed, and when the surface temperature is reduced to below 200 ℃, cold straightening is performed by a cold straightener.

8. The method for manufacturing a stainless steel composite plate having an excellent plate shape according to claim 1, wherein after intermittent cooling, the composite plate large plate directly enters a straightener for straightening;

9. The method for manufacturing a stainless steel composite plate having an excellent plate shape according to claim 1, wherein the composite blank manufacturing step specifically comprises:

coating a release agent on one surface of a composite material;

overlaying the grooves on the four sides of the composite blank base blank;

10. The method for manufacturing a stainless steel composite plate having excellent plate shape according to claim 1, wherein the chemical composition of the base material of the composite blank is as follows in mass percent: c:0.03 to 0.07 percent, si:0.11 to 0.19 percent, mn:1.46 to 1.54 percent, P is less than or equal to 0.010 percent, S is less than or equal to 0.0015 percent, cr:0.21 to 0.29 percent, ni:0.16 to 0.24 percent, cu:0.16 to 0.24 percent, mo:0.16 to 0.24 percent, nb:0.026 to 0.034 percent, ti: 0.011-0.019%, al:0.030 to 0.040 percent, and the balance of Fe and unavoidable impurities.

11. A stainless steel composite panel having an excellent plate shape, characterized in that the composite panel is manufactured by the manufacturing method according to any one of claims 1 to 10.

12. The stainless steel composite plate with excellent plate shape according to claim 11, wherein the total thickness of the composite plate is not less than 19mm, the thickness of the base layer is not less than 16mm, the thickness of the composite layer is 1-10 mm, the difference of Vickers hardness in the thickness direction of the base layer of the composite plate is not more than 10, the difference of strength between the head and the tail is not more than 40MPa, the difference of strength of the whole plate is not more than 40MPa, and the unevenness is not more than 2mm/m.

13. The stainless steel composite plate with excellent plate shape according to claim 11, wherein the yield strength of the composite plate is not less than 345MPa, the tensile strength is not less than 490MPa, the elongation after break is not less than 18%, and the yield ratio is not more than 0.85; the bonding rate of the composite interface is 100%, and the shearing strength is more than or equal to 300MPa; the impact energy at 0 ℃ is more than or equal to 120J, the impact energy at-20 ℃ is more than or equal to 120J, and the impact energy at-40 ℃ is more than or equal to 120J.

14. The stainless steel composite plate with excellent plate shape according to claim 11, wherein the yield strength of the composite plate is not less than 500MPa, the tensile strength is not less than 630MPa, the elongation after break is not less than 18%, and the yield ratio is not more than 0.86; the impact energy at 0 ℃ is more than or equal to 240J, the impact energy at-20 ℃ is more than or equal to 200J, and the impact energy at-40 ℃ is more than or equal to 150J.