High-temperature-oxidation-resistant and environment-corrosion-resistant hot-formed composite steel plate and preparation method thereof

Abstract

The invention relates to the technical field of materials, and particularly discloses a high-temperature-oxidation-resistant and environment-corrosion-resistant hot-forming composite steel plate which comprises a middle plate layer, outer plate layers are arranged on the two sides of the middle plate layer, each outer plate layer comprises a stainless steel band, and the stainless steel bands are located on the sides, away from the middle plate layer, of the outer plate layers; the middle plate layer comprises a boron steel plate, and the ratio of the thickness of any stainless steel band to the total thickness of the boron steel plate is 1: 10-1: 50. The invention provides the high-temperature-oxidation-resistant and environment-corrosion-resistant hot-formed composite steel plate with better toughness and oxidation performance, and meanwhile, the preparation difficulty is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and in particular to a high temperature oxidation resistant and environmental corrosion resistant hot formed composite steel plate and a preparation method thereof. Background Art

[0002] In the past 10 years, the use of hot-formed steel in automobiles has increased year by year, and the average use of hot-formed parts has reached 8 to 20 pieces per vehicle. The development of the domestic hot-forming industry still faces difficulties and bottlenecks. Anti-oxidation, corrosion resistance, and high toughness are the most prominent contradictions in the development of hot-forming technology. ArcelorMittal proposed the aluminum-silicon coating technology in 1999, which effectively avoided the problem of surface oxidation of uncoated hot-stamped steel plates, but the above coating process could not solve the problem of insufficient toughness at the same time. In 2019, Yucaitang invented the technology of thin aluminum-silicon coating, which uses methods such as reducing the thickness of the coating and optimizing the heating process to protect the surface of the hot-forming material, and has now been applied in mass production.

[0003] Compared with conventional aluminum-silicon coatings, the coating preparation process under thin coating conditions is more difficult, and it is difficult to stably prepare a coating with uniform and stable thickness during industrialization. Therefore, it is necessary to develop a hot-formed steel that breaks through the limitations of toughness and oxidation performance. Summary of the invention

[0004] The present invention aims to provide a high-temperature oxidation-resistant and environmental corrosion-resistant hot-formed composite steel plate with better toughness and oxidation performance and a preparation method thereof, while reducing the difficulty of preparation.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a high-temperature oxidation-resistant and environmental corrosion-resistant hot-formed composite steel plate, comprising a middle plate layer, outer plate layers are arranged on both sides of the middle plate layer, the outer plate layer comprises a stainless steel belt, and the stainless steel belt is located on the side of the outer plate layer away from the middle plate layer; the middle plate layer comprises a boron steel plate, and the ratio of the thickness of any stainless steel belt to the total thickness of the boron steel plate is 1:10 to 1:50.

[0006] The beneficial effects of this program are:

[0007] Stainless steel strips have better high temperature resistance, oxidation resistance and environmental corrosion resistance. The composite steel plate in this solution uses the stainless steel strip as the outermost layer, which can prevent oxygen and corrosive liquids from contacting the middle plate layer during use. Therefore, the middle plate layer will not be corroded in high temperature and corrosive liquids, making the composite steel plate in this solution have better high temperature resistance, oxidation resistance and environmental corrosion resistance. Compared with ordinary stainless steel plates, the middle plate layer in this solution includes boron steel plates, which have greater strength, making the composite steel plate also have greater strength.

[0008] At present, composite steel plates usually use aluminum silicon coating technology or thin aluminum silicon coating technology to directly coat the surface of hot forming materials, and the coating protects the hot forming materials. On this basis, although the high temperature oxidation resistance and environmental corrosion resistance of stainless steel are better than those of boron steel plates, some fields have higher strength requirements for steel plates, which need to withstand pressures of 2GPa and above, while the strength of stainless steel plates is lower and can only withstand a maximum pressure of 7 to 800MPa. Introducing stainless steel plates while limiting the thickness of the composite plates will result in the strength of the composite steel plates failing to meet the requirements. Therefore, in order to improve the high temperature oxidation resistance and environmental corrosion resistance, this field can only adjust the coating process.

[0009] During the experiment, the inventor accidentally discovered that when the thickness of each stainless steel strip is 1:10 to 1:50 of the thickness of all boron steel plates, even if the stainless steel strip is present, the strength of the composite steel plate in the present invention will not be significantly reduced compared with the steel plate of the same thickness made by coating technology, so that the composite steel plate in this scheme can still be used in fields with high strength requirements.

[0010] Compared with the coating, the stainless steel in this solution is thicker and less likely to be damaged or fall off during use, so it has a longer service life; the processing technology is simpler, the quality stability of mass production is better, and it is more suitable for industrial applications.

[0011] Furthermore, multiple boron steel plates and stainless steel strips are provided, and the boron steel plates and stainless steel strips are alternately distributed, and the ratio of the thickness of any stainless steel strip to the total thickness of all the boron steel plates is 1:10 to 1:50.

[0012] Furthermore, the boron steel sheet is one or more of Mn-B, Mn-B-Nb, Mn-B-Nb-V, Mn-Mo-B, Mn-Cr-B, Mn-Cr, Mn-VB and Mn-W-Ti-B.

[0013] Furthermore, the stainless steel strip is one or more of 316, 443, 304 and 430.

[0014] The beneficial effects of this solution are: the steel plate in this solution has high strength, the stainless steel strip has better resistance to high temperature oxidation and environmental corrosion, and the prepared composite steel plate can better meet the fields with higher strength requirements.

[0015] The present invention discloses a method for preparing a high temperature oxidation resistant and environmental corrosion resistant hot-formed composite steel plate, which is used to prepare the composite steel plate, comprising the following steps:

[0016] Step 1: Preparation: alternately stack stainless steel strips and boron steel plates to obtain a multi-layer plate, and make two of the stainless steel strips located at the outermost layer of the multi-layer plate;

[0017] Step 2, hot rolling: hot rolling the multilayer plate until the deformation of the multilayer plate is greater than or equal to 90-98%, thereby obtaining a hot-rolled steel plate;

[0018] Step 3, cold rolling: cold rolling the hot-rolled steel plate until the deformation of the hot-rolled steel plate is 60-80%, thereby obtaining a cold-rolled steel plate;

[0019] Step 4, hot stamping: heat the cold-rolled steel sheet to a temperature greater than or equal to 930° C., keep the temperature for 5 minutes, and then perform hot stamping.

[0020] The beneficial effects of this solution are as follows: the stainless steel strip used in this solution is in the form of a film covering the middle plate layer, effectively isolating the middle plate layer from contact with external oxygen and corrosive liquids. When the middle plate layer and the stainless steel strip are used to prepare the composite plate, it is only necessary to perform hot rolling and cold rolling on the multilayer plate. During the hot rolling and cold rolling process, the stainless steel strip and the middle plate layer are deformed synchronously, and the thickness of the stainless steel strip can be controlled by the deformation of the multilayer plate and the hot-rolled steel plate during hot rolling and cold rolling, so that it is easier to obtain a composite steel plate with uniform and stable thickness of each layer, and the preparation cost is lower.

[0021] Furthermore, the hot rolling in step 2 is divided into 3 to 8 rolling passes.

[0022] Furthermore, the cold rolling in step 3 is divided into 4 to 6 rolling passes.

[0023] The beneficial effect of this solution is that rolling in multiple passes is more conducive to controlling the deformation of the plate and improving the surface quality of the obtained composite steel plate.

[0024] Furthermore, in step 2, after all the rolling passes are completed, and in step 3, after all the rolling passes are completed, annealing treatment is performed, the annealing temperature is 600-850° C., and the annealing time is 2-10 minutes.

[0025] The beneficial effects of this solution are: annealing can promote the bonding of the stainless steel strip and the middle plate layer, while reducing the stress inside the plate and improving the rolling quality.

[0026] Furthermore, the rolling speed of step 2 and step 3 is 2 to 5 m / min.

[0027] Furthermore, after the multilayer board is obtained in step 1, the multilayer board is welded.

[0028] The beneficial effect of this solution is that welding can preliminarily fix the stacked stainless steel strips and middle plate layers, so that no other fixing structures are required and no relative sliding occurs during hot rolling and cold rolling, further improving the rolling quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A metallographic diagram of a cross-sectional position of a composite steel plate of the present invention;

[0030] Figure 2 for Figure 1 Metallographic diagram of the contact position between the middle plate layer and the outer plate layer;

[0031] Figure 3 for Figure 1 A partial enlarged view of

[0032] Figure 4 for Figure 3 A partial enlarged view of

[0033] Figure 5 The static tensile properties test results of the composite steel plate prepared in the present invention are shown. DETAILED DESCRIPTION

[0034] The following is further described in detail through specific implementation methods:

[0035] Example

[0036] The embodiment discloses a high temperature oxidation resistant and environmental corrosion resistant hot formed composite steel plate, including a middle plate layer, outer plate layers are arranged on both sides of the middle plate layer, and the outer plate layers are attached to the middle plate layer. The outer plate layer in this embodiment is a stainless steel strip, and the middle plate layer is a boron steel plate. In actual implementation, multiple boron steel plates and stainless steel strips can be provided, and the boron steel plates and stainless steel strips are alternately distributed, wherein the number of boron steel plates is n, and the number of stainless steel strips is n+1, ensuring that the two outermost plates are both stainless steel strips, and the ratio of the thickness of any stainless steel strip to the total thickness of all boron steel plates is 1:10 to 1:50.

[0037] The boron steel plate is one or more of Mn-B, Mn-B-Nb, Mn-B-Nb-V, Mn-Mo-B, Mn-Cr-B, Mn-Cr, Mn-VB and Mn-W-Ti-B; the stainless steel strip is one or more of 316, 443, 304 and 430.

[0038] The present invention also discloses a method for preparing the above-mentioned high temperature oxidation resistant and environmental corrosion resistant hot-formed composite steel plate, comprising the following steps:

[0039] Step 1: Preparation: The boron steel plate uses 22MnB5 steel plate and the stainless steel strip uses SUS316. The surfaces of the boron steel plate and the stainless steel strip are polished and cleaned. Then, the stainless steel strip and the boron steel plate are alternately stacked to obtain a multi-layer plate, and two of the stainless steel strips are located at the outermost layer of the multi-plate. Finally, the superimposed surfaces are welded and fixed by vacuum ion beam.

[0040] Step 2, hot rolling: hot rolling the multilayer plate, the hot rolling is divided into 3 to 8 rolling passes, until the deformation of the multilayer plate is greater than or equal to 90 to 98%, to obtain a hot-rolled steel plate, and annealing the hot-rolled steel plate;

[0041] Step 3, cold rolling: cold rolling the hot-rolled steel sheet after the treatment in step 2, the cold rolling is divided into 4 to 6 rolling passes, until the deformation of the hot-rolled steel sheet is 60 to 80%, and the cold-rolled steel sheet is obtained, and then annealing the cold-rolled steel sheet, wherein the rolling speeds of the cold rolling and the hot rolling are both 2 to 5 m / min, and the temperature of the two annealing treatments is 600 to 850° C., and the annealing time is 2 to 10 min;

[0042] Step 4, hot stamping: heat the cold-rolled steel plate to a temperature greater than or equal to 930°C and keep it warm for 5 minutes, then perform hot stamping without atmosphere protection to obtain a composite steel plate. Specifically, the size of the hot stamping is determined according to the actual requirements for storage, sales, transportation and other applications.

[0043] The present invention also discloses Example 1, which uses one middle plate layer and two outer plate layers to make a composite steel plate, and the cross-sectional metallographic image of the composite steel plate is as follows: Figures 1 to 4 shown.

[0044] The present invention also uses a 22MnB5 steel plate with the same thickness as the composite steel plate of Example 1 as Comparative Example 1, and tests the mechanical properties of the composite steel plate and the 22MnB5 steel plate. The test results are shown in the following table and Figure 2 As shown:

[0045]

[0046]

[0047] Combining the above detection and test results, we can know that:

[0048] 1. According to Figure 1 , Figure 3 and Figure 4 The composite steel plate has a three-layer structure, and two stainless steel belts are located on both sides of the middle plate layer. The middle plate layer is a typical martensitic structure, and after hot stamping, it does not oxidize even without atmosphere protection at high temperature, indicating that the stainless steel belt has a protective effect on the middle plate layer, that is, the composite steel plate in the present invention has high temperature oxidation resistance.

[0049] 2. According to Figure 2 There is an obvious interdiffusion layer at the interface between the outer plate layer and the middle plate layer, indicating that the stainless steel layer and the base steel layer have good metallurgical bonding properties, the matrix and the diffusion zone maintain a good crystallographic matching relationship, and there is no risk of separation between the outer plate layer and the middle plate layer during use.

[0050] 3. According to the above table and Figure 5The tensile strength of the composite steel plate prepared by the present invention is better, while the yield strength does not decrease significantly, indicating that the introduction of the stainless steel strip does not significantly reduce the mechanical properties of the boron steel plate. Compared with ordinary boron steel plates, the composite steel plate in this scheme also has environmental corrosion resistance and is more suitable as a safety structural member, a reinforced structural member, a wheel component, a high-strength and tough automotive structural member or a chassis component of a motor vehicle, including but not limited to the A-pillar, B-pillar, bumper, anti-collision beam, roof frame, bottom frame and other parts of the automobile.

[0051] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. High temperature oxidation resistant and environmental corrosion resistant hot-formed composite steel plate, characterized by: It comprises a middle plate layer, both sides of which are provided with outer plate layers, the outer plate layers comprise stainless steel strips, and the stainless steel strips are located on the side of the outer plate layer away from the middle plate layer; the middle plate layer comprises boron steel plates, and the ratio of the thickness of any stainless steel strip to the total thickness of the boron steel plates is 1:10 to 1:

50.

2. The high temperature oxidation resistant and environmental corrosion resistant hot formed composite steel plate according to claim 1, characterized in that: There are multiple boron steel plates and stainless steel strips, and the boron steel plates and stainless steel strips are alternately distributed, and the ratio of the thickness of any stainless steel strip to the total thickness of all the boron steel plates is 1:10 to 1:

50.

3. The high temperature oxidation resistant and environmental corrosion resistant hot formed composite steel plate according to claim 1, characterized in that: The boron steel sheet is one or more of Mn-B, Mn-B-Nb, Mn-B-Nb-V, Mn-Mo-B, Mn-Cr-B, Mn-Cr, Mn-VB and Mn-W-Ti-B.

4. The high temperature oxidation resistant and environmental corrosion resistant hot formed composite steel plate according to claim 1, characterized in that: The stainless steel strip is one or more of 316, 443, 304 and 430.

5. A method for preparing a hot-formed composite steel plate resistant to high temperature oxidation and environmental corrosion, characterized in that: The following steps are involved: Step 1: Preparation: alternately stack stainless steel strips and boron steel plates to obtain a multi-layer plate, and make two of the stainless steel strips located at the outermost layer of the multi-layer plate; Step 2, hot rolling: hot rolling the multilayer plate until the deformation of the multilayer plate is greater than or equal to 90-98%, thereby obtaining a hot-rolled steel plate; Step 3, cold rolling: cold rolling the hot-rolled steel plate until the deformation of the hot-rolled steel plate is 60-80%, thereby obtaining a cold-rolled steel plate; Step 4, hot stamping: heat the cold-rolled steel sheet to a temperature greater than or equal to 930° C., keep the temperature for 5 minutes, and then perform hot stamping.

6. The method for preparing the high temperature oxidation resistant and environmental corrosion resistant hot-formed composite steel plate according to claim 5, characterized in that: The hot rolling in step 2 is divided into 3 to 8 rolling passes.

7. The method for preparing the high temperature oxidation resistant and environmental corrosion resistant hot-formed composite steel plate according to claim 5, characterized in that: The cold rolling in step 3 is divided into 4 to 6 rolling passes.

8. The method for preparing a high temperature oxidation resistant and environmental corrosion resistant hot-formed composite steel plate according to any one of claims 5 to 7, characterized in that: Annealing treatment is performed in step 2 after all rolling passes are completed and in step 3 after all rolling passes are completed. The annealing temperature is 600-850° C. and the annealing time is 2-10 minutes.

9. The method for preparing the high temperature oxidation resistant and environmental corrosion resistant hot-formed composite steel plate according to claim 8, characterized in that: The rolling speed of step 2 and step 3 is 2-5 m / min.

10. The method for preparing the high temperature oxidation resistant and environmental corrosion resistant hot-formed composite steel plate according to claim 5, characterized in that: Step 1: After obtaining the multi-layer board, the multi-layer board is welded.

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