CN116274362A - Super-thick stainless steel composite board and preparation method thereof - Google Patents
Super-thick stainless steel composite board and preparation method thereof Download PDFInfo
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- CN116274362A CN116274362A CN202310179681.1A CN202310179681A CN116274362A CN 116274362 A CN116274362 A CN 116274362A CN 202310179681 A CN202310179681 A CN 202310179681A CN 116274362 A CN116274362 A CN 116274362A
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Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/38—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling sheets of limited length, e.g. folded sheets, superimposed sheets, pack rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B15/00—Arrangements for performing additional metal-working operations specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
- B21B3/02—Rolling special iron alloys, e.g. stainless steel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/004—Heating the product
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
- B21B45/0203—Cooling
- B21B45/0209—Cooling devices, e.g. using gaseous coolants
- B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
- B21B45/0218—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes for strips, sheets, or plates
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/38—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling sheets of limited length, e.g. folded sheets, superimposed sheets, pack rolling
- B21B2001/386—Plates
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B2261/00—Product parameters
- B21B2261/20—Temperature
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Metal Rolling (AREA)
Abstract
The invention discloses an extra-thick stainless steel composite board and a preparation method thereof. The thickness of the composite board is more than 35mm, the thickness of the corresponding composite blank is more than 490mm, in the rough rolling stage, the finishing rolling temperature is more than or equal to 1000 ℃, the finishing rolling temperature in the finish rolling stage is more than or equal to 780 ℃, the composite board large board is cooled after rolling is finished, the composite board large board enters an ultra-fast cooling system, 2-4 groups of cooling headers are opened every time, then 2-4 groups of cooling headers are not opened, the cooling water pressure is 0.2MPa, the cooling speed is 3-15 ℃/s, the finishing cooling temperature is 380-450 ℃, and the roller way speed is 0.6-0.9 m/s; the large composite plate firstly enters from the inlet of the ultra-fast cooling system in the forward direction, when the head of the large composite plate reaches the 24 th group of cooling headers, the roller way is reversed, and the large composite plate reversely passes through the ultra-fast cooling system and leaves from the inlet of the ultra-fast cooling system to finish intermittent cooling.
Description
Technical Field
The invention belongs to the technical field of steel material preparation, and relates to an extra-thick stainless steel composite plate 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.
Along with the implementation of national expressways and railway network construction and the great investment of infrastructure construction, the rapid development of bridge manufacturing industry is promoted. 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 plate has the problems of poor plate shape and poor uniformity, and the problems of plate shape and uniformity are more serious for the super-thick steel plate.
Disclosure of Invention
The invention aims to provide an extra-thick stainless steel composite board and a preparation method thereof.
In order to achieve the above object, an embodiment of the present invention provides a method for manufacturing an extra-thick stainless steel composite plate, which includes three steps of composite blank manufacturing, composite blank rolling, and composite plate separation and straightening, which are sequentially performed;
in the composite blank preparation step, preparing a composite blank with a stacking sequence of a base material, a composite material and a base material;
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 in the finish rolling stage is more than or equal to 780 ℃, and obtaining a large composite board with the thickness more than or equal to 70 mm;
after rolling, cooling, and enabling the large composite plate to enter an ultra-fast cooling system for intermittent cooling: the open-close state of all 24 groups of cooling headers of the ultra-fast cooling system is 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 is 0.6-0.9M/s; wherein N takes the value of 2, 3 or 4, M takes the value of 2, 3 or 4; the large composite plate firstly enters from the inlet of the ultra-fast cooling system in the forward direction, when the head of the large composite plate reaches the 24 th group of cooling headers, the roller way is reversed, and the large composite plate reversely passes through the ultra-fast cooling system and leaves from the inlet of the ultra-fast cooling system to finish intermittent cooling.
Preferably, the cooling distance of each set of cooling headers is 1m.
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; and 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.
Preferably, 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, the preparation step of the composite blank comprises billet preparation, billet surface treatment, spacer brushing, assembly, seal wrapping, gas shielded welding, surfacing, vacuumizing and sealing;
wherein the vacuum degree of the vacuumized water is less than or equal to 10 -1 Pa, maintaining the pressure for 4h.
Preferably, the components of the used release agent are as follows by weight: 25-35% of silicon nitride, 5-10% of thermosetting amino resin and 55-70% of water;
the thickness of the coating release agent is 0.2-0.5 mm;
before assembly, the composite material coated with the release agent is heated and dried at 100-250 ℃ for 20-40 min.
Preferably, the components of the used release agent are as follows by weight: 25-35% of silicon nitride, 5-10% of thermosetting amino resin and 55-70% of water;
the thickness of the coating release agent is 0.2-0.5 mm;
before assembly, the composite material coated with the release agent is heated and dried at 100-250 ℃ for 20-40 min.
Preferably, in the gas shielded welding, the welding speed is 300-360 mm/min, and the temperature between the welding process control channels is 135-165 ℃.
Preferably, submerged arc overlay welding is used in the overlay welding;
before welding, baking the welding flux for 2 hours at 350 ℃, and then preserving heat for 1 hour at 150 ℃;
In the welding process, the temperature between the channels is controlled to be 135-165 ℃, and the welding speed is 420-480 mm/min.
Preferably, when the composite board large board passes through the ultra-fast cooling system, the cooling headers of the 1 st to 4 th groups are opened, the cooling headers of the 5 th to 8 th groups are not opened, the cooling headers of the 9 th to 12 th groups are opened, the cooling headers of the 13 th to 16 th groups are not opened, the cooling headers of the 17 th to 20 th groups are opened, the cooling headers of the 21 st to 22 th groups are not opened, and the cooling headers of the 23 rd to 24 th groups are opened;
and after the large composite board leaves from the inlet of the ultra-rapid cooling system, naturally cooling the large composite board to room temperature by using the upper cooling bed. In order to achieve the above purpose, an embodiment of the present invention provides an extra-thick stainless steel composite board, wherein the chemical components of the base layer are as follows by 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; the composite board is prepared by the preparation method.
Preferably, the total thickness of the composite board is more than or equal to 35mm, the thickness of the base layer is more than or equal to 32mm, 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 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, through intermittent cooling, especially forward water penetration, reverse water penetration is carried out when the head reaches the 24 th group of cooling headers, and the control of the roller speed is combined, so that the shape and uniformity are greatly improved, the mechanical property and toughness can be ensured, the shape control and uniformity control of the super-thick plate are realized, and the production difficulty of the existing super-thick stainless steel composite plate is overcome; 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 billet according to a first embodiment of the billet surface treatment step of the present invention;
FIG. 2 is a schematic cross-sectional view of a composite blank corresponding to FIG. 1;
FIG. 3 is a block flow diagram of a composite billet rolling step according to an embodiment of the present invention;
fig. 4 is a schematic cross-sectional view of two single-sided stainless steel composite panels rolled from the composite blank of fig. 2.
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;
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;
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.
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 composite blank obtained in the composite blank preparation stepThe ratio of the thickness to the thickness of the subsequently rolled composite slab, also known as the composite slab 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 pressure holding for more than 4 hours can ensureVacuum degree. 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. 3, the clad-blank rolling step includes the following sub-steps:
heating the obtained composite blank, wherein the soaking temperature is 1170-1220 ℃, preferably 1200-1220 ℃, the total heating time is more than or equal to 1.2 Xt min/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 below 840 ℃, preferably below 830 ℃, the finish rolling stage is started; the finishing temperature in the finish rolling stage is more than or equal to 780 ℃, preferably more than or equal to 800 ℃, and the total rolling reduction of finish rolling is 55-75%, so that a composite board large plate with the thickness of more than or equal to 70mm is obtained;
After rolling, cooling, and enabling the large composite plate to enter an ultra-fast cooling system for intermittent cooling: the open-close state of all 24 groups of cooling headers of the ultra-fast cooling system is 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 is 0.6-0.9M/s; wherein N takes the value of 2, 3 or 4, M takes the value of 2, 3 or 4; the large composite plate firstly enters from the inlet of the ultra-fast cooling system in the forward direction, when the head of the large composite plate reaches the 24 th group of cooling headers, the roller way is reversed, and the large composite plate reversely passes through the ultra-fast cooling system and leaves from the inlet of the ultra-fast cooling system to finish intermittent cooling;
and after the intermittent cooling is finished, the cooling bed on the large composite board is naturally cooled to the room temperature, and the rolling of the composite blank in the step 2) is finished so as to enter the separation and straightening of the composite board in the step 3).
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.
Preferably, the cooling distance of each set of cooling headers is 1m. That is, when the 1-group cooling header is on, it can cool the approximately 1m length section of the composite plate on the roller table.
When the composite board passes through the ultra-fast cooling system, the cooling headers of the 1 st to 4 th groups are opened, the cooling headers of the 5 th to 8 th groups are not opened, the cooling headers of the 9 th to 12 th groups are opened, the cooling headers of the 13 th to 16 th groups are not opened, the cooling headers of the 17 th to 20 th groups are opened, the cooling headers of the 21 st to 22 th groups are not opened, and the cooling headers of the 23 rd to 24 th groups are opened.
For example, in one test example, a Q500Q steel grade was selected as the substrate; and selecting 316L stainless steel as a composite material. A composite blank having a thickness of 490mm and a constant substrate thickness was prepared according to this embodiment. According to the embodiment, the composite blank is rolled into a large composite board with the thickness of 70mm, and the large composite board is implemented according to the step of separating and straightening the composite board, which is described later, so as to obtain a finished product of the single-sided stainless steel composite board with the total thickness of 35mm, the base layer thickness of 32mm and the multi-layer thickness of 3 mm.
The composite board of the test example is sampled and tested, the interface bonding rate is 100%, the inward bending is qualified by 180 degrees (no crack), the outward bending is qualified by 180 degrees (no crack), the composite board is boiled in sulfuric acid-copper sulfate solution for 20 hours, after 180 degrees bending, the composite board has no intergranular corrosion crack, the yield strength is 545MPa, the tensile strength is 672MPa, the elongation after breaking is 24%, and the yield ratio is 0.81; -40 ℃ impact energy 263J. The Vickers hardness difference of the base layer in the thickness direction is 9, the strength difference between the head and the tail is less than or equal to 37MPa, the strength difference of the whole plate at each position is less than or equal to 37MPa, the unevenness is less than or equal to 2mm/m, and the shearing strength is 404MPa.
< second embodiment of composite Rolling step >
In this embodiment, the composite billet rolling step includes 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 when the surface temperature of the intermediate billet is reduced to below 840 ℃, starting a finish rolling stage, wherein the initial rolling temperature of the finish rolling stage is 810-840 ℃ and the final rolling temperature is 780-810 ℃, so as to obtain a large composite board with the thickness of more than or equal to 70 mm;
After rolling, cooling, and enabling the large composite plate to enter an ultra-fast cooling system for intermittent cooling: the open-close state of all 24 groups of cooling headers of the ultra-fast cooling system is 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 is 0.6-0.9M/s; wherein N takes the value of 2, 3 or 4, M takes the value of 2, 3 or 4; the large composite plate firstly enters from the inlet of the ultra-fast cooling system in the forward direction, when the head of the large composite plate reaches the 24 th group of cooling headers, the roller way is reversed, and the large composite plate reversely passes through the ultra-fast cooling system and leaves from the inlet of the ultra-fast cooling system to finish intermittent cooling;
and after the intermittent cooling is finished, the cooling bed on the large composite board is naturally cooled to the room temperature, and the rolling of the composite blank in the step 2) is finished so as to enter the separation and straightening of the composite board in the step 3).
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.
For example, in one test example, a Q500Q steel grade was selected as the substrate; and selecting 316L stainless steel as a composite material. A composite blank having a thickness of 490mm and a constant substrate thickness was prepared according to this embodiment. According to the embodiment, the composite blank is rolled into a large composite board with the thickness of 70mm, and the large composite board is implemented according to the step of separating and straightening the composite board, which is described later, so as to obtain a finished product of the single-sided stainless steel composite board with the total thickness of 35mm, the base layer thickness of 32mm and the multi-layer thickness of 3 mm.
The composite board of the test example is sampled and tested, the interface bonding rate is 100%, the inward bending is qualified by 180 degrees (no crack), the outward bending is qualified by 180 degrees (no crack), the composite board is boiled in sulfuric acid-copper sulfate solution for 20 hours, after 180 degrees bending, the composite board has no intergranular corrosion crack, the yield strength is 546MPa, the tensile strength is 669MPa, the elongation after breaking is 24%, and the yield ratio is 0.82; impact energy 268J at-40 ℃. The Vickers hardness difference of the base layer in the thickness direction is 9, the strength difference between the head and the tail is less than or equal to 37MPa, the strength difference of the whole plate at each position is less than or equal to 37MPa, the unevenness is less than or equal to 2mm/m, and the shearing strength is 437MPa.
< third embodiment of composite Rolling step >
This embodiment is identical to the first embodiment and the second embodiment of the composite billet rolling step described above in terms of the steps of heating, two-stage controlled rolling, cooling, and the like, and differs only in that: after the intermittent cooling is completed.
In the first embodiment and the second embodiment of the composite blank rolling step, after the composite board big plate leaves the ultra-rapid cooling system, the composite board big plate is naturally cooled to room temperature by a cooling bed; in contrast, in the present embodiment, after the composite board leaves the ultra-rapid cooling system, the composite board directly enters the straightener to be straightened, the cooling bed on the straightened composite board is naturally cooled, and when the surface temperature is reduced to below 200 ℃, the cold straightening is performed by adopting the cold straightener. This can further promote the plate shape.
< fourth embodiment of composite Rolling step >
This embodiment is identical to the first embodiment and the second embodiment of the composite billet rolling step described above in terms of the steps of 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 embodiment and the second embodiment of the composite blank rolling step, after the composite board big plate leaves the ultra-rapid cooling system, the composite board big plate is naturally cooled to room temperature by a cooling bed; in contrast, in the present embodiment, after leaving the ultra-rapid cooling system, the composite plate is directly fed into a straightener for straightening 1 to 3 passes, unlike the first embodiment of the composite slab rolling step, in the present embodiment, the composite plate is then placed at a temperature T f Between two steel plates with the temperature of +100 ℃ to 150 ℃ is subjected to stack cooling, and the stack cooling time is 0.4min/mm×t+ -5 min, so that the composite board large board can be slowly cooled in the stack cooling time and can be clamped by the steel board 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, the liquid crystal display device comprises a liquid crystal display device,
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. For example, in the test example, the unevenness was reduced to 1mm/m or less by the stack cooling.
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. 4, corresponding to the five embodiments of the blank surface treatment steps described previously, fig. 4 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 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, the composite layer is still marked with the original composite material label and the base layer is still marked with the original base material label in fig. 4.
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 35mm, the thickness of the base layer is more than or equal to 32mm, 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 0.86. 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, in the whole preparation method, the corrosion resistance and mechanical strength of the stainless steel composite plate are ensured through specific control of the process, and the corrosion resistance and mechanical property are prevented from being degraded in the rolling process of the composite blank; on the other hand, the plate shape control and uniformity control of the ultra-thick plate are realized, and the production difficulty of the existing ultra-thick stainless steel composite plate is overcome; 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.
Claims (14)
1. The preparation method of the ultra-thick stainless steel composite board is characterized by comprising three steps of composite blank preparation, composite blank rolling and composite board separation and straightening which are sequentially carried out;
in the composite blank preparation step, preparing a composite blank with a stacking sequence of a base material, a composite material and a base material;
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 in the finish rolling stage is more than or equal to 780 ℃, and obtaining a large composite board with the thickness more than or equal to 70 mm;
after rolling, cooling, and enabling the large composite plate to enter an ultra-fast cooling system for intermittent cooling: the open-close state of all 24 groups of cooling headers of the ultra-fast cooling system is 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 is 0.6-0.9M/s; wherein N takes the value of 2, 3 or 4, M takes the value of 2, 3 or 4; the large composite plate firstly enters from the inlet of the ultra-fast cooling system in the forward direction, when the head of the large composite plate reaches the 24 th group of cooling headers, the roller way is reversed, and the large composite plate reversely passes through the ultra-fast cooling system and leaves from the inlet of the ultra-fast cooling system to finish intermittent cooling.
2. The method of manufacturing an extra thick stainless steel composite sheet according to claim 1 wherein the cooling distance of each set of cooling headers is 1m.
3. The method for preparing the ultra-thick stainless steel composite plate according to claim 1, wherein 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) t min/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) t min/mm.
4. The method for preparing an extra-thick stainless steel composite plate according to claim 1, wherein in the step of adopting rough rolling and finish rolling in two-stage controlled rolling, longitudinal rolling is adopted in the 1 st pass in the rough rolling stage, 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; and 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.
5. The method for manufacturing an extra-thick stainless steel composite panel according to claim 4, wherein the rolling temperature of the 1 st pass is equal to or higher than 1060 ℃, the initial rolling temperature of the rest passes is equal to or lower than 1050 ℃, and the final rolling temperature is equal to or higher than 1000 ℃ in the whole rough rolling stage; 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 ℃.
6. The method for preparing the ultra-thick stainless steel composite plate according to claim 1, wherein the composite blank preparation step comprises billet preparation, blank surface treatment, coating with a release agent, assembly, seal wrapping, gas shield welding, surfacing, vacuumizing and sealing;
wherein the vacuum degree of the vacuumized water is less than or equal to 10 -1 Pa, maintaining the pressure for 4h.
7. The method for preparing the ultra-thick stainless steel composite plate according to claim 6, wherein the components of the used isolating agent are as follows by weight: 25-35% of silicon nitride, 5-10% of thermosetting amino resin and 55-70% of water;
the thickness of the coating release agent is 0.2-0.5 mm;
before assembly, the composite material coated with the release agent is heated and dried at 100-250 ℃ for 20-40 min.
8. The method for preparing the ultra-thick stainless steel composite plate according to claim 6, wherein the components of the used isolating agent are as follows by weight: 25-35% of silicon nitride, 5-10% of thermosetting amino resin and 55-70% of water;
the thickness of the coating release agent is 0.2-0.5 mm;
before assembly, the composite material coated with the release agent is heated and dried at 100-250 ℃ for 20-40 min.
9. The method for manufacturing an extra thick stainless steel composite sheet according to claim 6, wherein the welding speed is 300-360 mm/min and the inter-channel temperature is 135-165 ℃ during the welding process.
10. The method for manufacturing an ultra-thick stainless steel composite plate according to claim 6, wherein submerged arc overlaying is adopted in the overlaying;
before welding, baking the welding flux for 2 hours at 350 ℃, and then preserving heat for 1 hour at 150 ℃;
in the welding process, the temperature between the channels is controlled to be 135-165 ℃, and the welding speed is 420-480 mm/min.
11. The method for manufacturing a super-thick stainless steel composite plate according to claim 1, wherein when the composite plate passes through the super-rapid cooling system, the cooling headers of the 1 st to 4 th groups are opened, the cooling headers of the 5 th to 8 th groups are not opened, the cooling headers of the 9 th to 12 th groups are opened, the cooling headers of the 13 th to 16 th groups are not opened, the cooling headers of the 17 th to 20 th groups are opened, the cooling headers of the 21 st to 22 th groups are not opened, and the cooling headers of the 23 rd to 24 th groups are opened;
And after the large composite board leaves from the inlet of the ultra-rapid cooling system, naturally cooling the large composite board to room temperature by using the upper cooling bed.
12. The ultra-thick stainless steel composite board is characterized in that the chemical components of the base layer are as follows in percentage by mass: 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, wherein the composite plate is prepared by the preparation method of any one of claims 1 to 11.
13. The ultra-thick stainless steel composite board according to claim 12, wherein the total thickness of the composite board is more than or equal to 35mm, the thickness of a base layer is more than or equal to 32mm, the thickness of a composite layer is 1-10 mm, the difference of Vickers hardness in the thickness direction of the base layer of the composite board is less than or equal to 10, the difference of strength between the head and the tail is less than or equal to 40MPa, the difference of strength of the whole board is less than or equal to 40MPa, and the unevenness is less than or equal to 2mm/m.
14. The extra thick stainless steel composite panel according to claim 12, wherein the composite panel has a yield strength of not less than 500MPa, a tensile strength of not less than 630MPa, an elongation after break of not less than 18%, and a yield ratio of 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.
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