STEEL FOR HIGH-STRENGTH ALUMINUM CLAD SUBSTRATE AND MANUFACTURING METHOD THEREFOR

Abstract

A steel for high-strength aluminum clad substrate, comprising the following chemical elements by mass percent: C: 0.008-0.02%, 0<Si≤0.005%, Mn: 0.25-0.5%, P: 0.018-0.03%, Al≤0.005%, N: 0.0040-0.010%, Ti: 0.02-0.04%, O: 0.02-0.050%, and the balance being Fe and other inevitable impurities. The manufacturing method therefor comprises the steps of: (1) smelting and casting; (2) reheating: reheating a casting blank to 1180° C.-1250° C.; (3) rough rolling; (4) finish rolling; (5) coiling; and (6) cooling to room temperature. The steel for high-strength aluminum clad substrate has good strength and good plasticity.

Claims

1. Steel for a high-strength aluminum clad substrate, characterized by comprising the following chemical elements by mass percent: C: 0.008-0.02%, O<Si≤_0.005%, Mn: 0.25-0.5%, P: 0.018-0.03%, Al≤_0.005%, N: 0.0040-0.010%, Ti: 0.02-0.04%, O: 0.02-0.050%, and the balance being Fe and other inevitable impurities.

2. The steel for a high-strength aluminum clad substrate according to claim 1, characterized in that the steel further satisfy at least one of Ti/(3.42N+4C)≥0.3 and O/(0.9Al+1.2Si)≥3.0.

3. The steel for a high-strength aluminum clad substrate according to claim 1, characterized in that the mass percents of all the chemical elements further satisfy at least one of the following items: C: 0.008-0.015%, P: 0.018-0.024%, N: 0.004-0.008%, O: 0.02-0.04%.

4. The steel for a high-strength aluminum clad substrate according to claim 1, characterized in that among the inevitable impurities, the mass percent of S is less than or equal to 0.005%.

5. The steel for a high-strength aluminum clad substrate according to claim 1, characterized in that a matrix of the steel is an equiaxed ferrite, a grain size of which is 10-50 microns.

6. The steel for a high-strength aluminum clad substrate according to claim 1, characterized in that the yield strength is 210-290 MPa, the tensile strength is greater than or equal to 320 MPa, and the elongation is greater than or equal to 40%.

7. A manufacturing method for the steel for a high-strength aluminum clad substrate according to claim 1, characterized by comprising the steps: (1) smelting and casting; (2) reheating: reheating a casting blank to 1180° C-1250° C.; (3) rough rolling; (4) finish rolling; (5) coiling; and (6) cooling to room temperature.

8. The manufacturing method according to claim 7, characterized in that at the step (3), the cumulative deformation in the rough rolling stage is greater than or equal to 80%, and the temperature at the end of rough rolling is in the range of 950° C.-1150° C.

9. The manufacturing method according to claim 7, characterized in that at the step (4), the final rolling temperature of the finish rolling is controlled to be 840-920° C.

10. The manufacturing method according to claim 7, characterized in that at the step (5), a steel plate after finish rolling is water-cooled to 580-640° C. for coiling.

11. The steel for a high-strength aluminum clad substrate of claim 2, wherein the yield strength is 210-290 MPa, the tensile strength is greater than or equal to 320 MPa, and the elongation is greater than or equal to 40%.

12. The steel for a high-strength aluminum clad substrate of claim 3, wherein the yield strength is 210-290 MPa, the tensile strength is greater than or equal to 320 MPa, and the elongation is greater than or equal to 40%.

13. The steel for a high-strength aluminum clad substrate of claim 4, wherein the yield strength is 210-290 MPa, the tensile strength is greater than or equal to 320 MPa, and the elongation is greater than or equal to 40%.

14. The steel for a high-strength aluminum clad substrate of claim 5, wherein the yield strength is 210-290 MPa, the tensile strength is greater than or equal to 320 MPa, and the elongation is greater than or equal to 40%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 illustrates a microstructure of steel for a high-strength aluminum clad substrate of Embodiment 1.

DETAILED DESCRIPTION OF THE INVENTION

[0044] The steel for a high-strength aluminum clad substrate and a manufacturing method therefor of the present invention will be further explained and described below in combination with specific embodiments and the accompanying drawings of the description. However, the explanation and description do not improperly limit the technical solution of the present invention.

Embodiments 1-8

[0045] Table 1 lists the mass percents (wt %) of all chemical elements in steel for a high-strength aluminum clad substrate of Embodiments 1-8.

TABLE-US-00001 TABLE 1 (wt %, the balance being Fe and other inevitable impurity elements in addition to S) Ti/ O/ Serial (3.42N + (0.9 Al + number C Si Mn P S Al Ti O N 4C) 1.2 Si) Embod- 0.0082 0.003 0.26 0.018 0.0031 0.0032 0.021 0.0307 0.0068 0.37 4.74 iment 1 Embod- 0.013 0.0037 0.25 0.024 0.0027 0.0011 0.0282 0.0423 0.0048 0.41 7.79 iment 2 Embod- 0.0148 0.0015 0.37 0.026 0.0019 0.0045 0.034 0.0283 0.0088 0.38 4.84 iment 3 Embod- 0.0122 0.005 0.33 0.019 0.0038 0.0012 0.032 0.0219 0.0065 0.45 3.09 iment 4 Embod- 0.0097 0.0046 0.28 0.028 0.0029 0.0011 0.024 0.0268 0.0072 0.38 4.12 iment 5 Embod- 0.017 0.0034 0.44 0.029 0.0045 0.0042 0.036 0.048 0.0061 0.41 6.11 iment 6 Embod- 0.013 0.0012 0.42 0.021 0.0047 0.0028 0.039 0.0235 0.0077 0.5 5.93 iment 7 Embod- 0.018 0.005 0.48 0.023 0.0033 0.0012 0.033 0.0407 0.0098 0.31 5.75 iment 8

[0046] It can be seen from Table 1 that compared with the prior art, the mass percents of Si and Al of all the embodiments of this application are all less than 0.005%; the mass percent of O is within 0.02-0.05%; and the mass percent of N is 0.0040-0.010%. In addition, in this application, P is added as a favorable element, so that the mass percent of P is controlled at 0.018-0.03%.

[0047] A manufacturing method for the steel for a high-strength aluminum clad substrate of Embodiments 1-8 adopts the following steps:

[0048] (1) Smelting and casting: smelting chemical element compositions shown in Table 1 in a 500 kg vacuum induction furnace, and casting to obtain a casting blank.

[0049] (2) Reheating: reheating the casting blank to 1180° C. -1250° C.

[0050] (3) Rough rolling: wherein the cumulative deformation in the rough rolling stage is greater than or equal to 80%, and the temperature at the end of rough rolling is 950° C. to 1150° C.

[0051] (4) Finish rolling: controlling a final rolling temperature of the finish rolling to be 840-920° C.

[0052] (5) Coiling: water-cooling the steel plate after finish rolling to 580-640° C. for coiling.

[0053] (6) Cooling to room temperature.

[0054] It should be noted that at the step (5), a cooling mode for coiling can also be air cooling in addition to water cooling. For example, when the steel for the high-strength aluminum clad substrate is thinner, such as ≤3.0mm, air cooling can also cause the steel for the high-strength aluminum clad substrate to be cooled to a desired coiling temperature before entering a coiling machine, and the property meets the requirements. [0055] Table 2 lists specific process parameters involved in the manufacturing method for the steel for the high-strength aluminum clad substrate of Embodiments 1-8.

TABLE-US-00002 TABLE 2 Step (3 ) Step (4) Step (5) Step (2) Accumu- Temperature Final Coiling Heating lative at end of rolling temper- Serial temperature defor- rough rolling temperature ature number (° C.) mation (%) (° C.) (° C.) (° C.) Embodi- 1180 85.4  980 876 589 ment 1 Embodi- 1202 84.2  984 888 590 ment 2 Embodi- 1195 83.4  960 905 583 ment 3 Embodi- 1211 83.2 1020 912 630 ment 4 Embodi- 1250 82.6 1021 914 624 ment 5 Embodi- 1220 82.2 1025 910 618 ment 6 Embodi- 1209 82.0 1032 908 620 ment 7 Embodi- 1198 81.6 1040 900 622 ment 8

[0056] Various tests are performed on the steel for the high-strength aluminum clad substrate of Embodiments 1-8. Test results are listed in Table 3.

TABLE-US-00003 TABLE 3 Thickness (μm) of steel- aluminum interface compound layer of Plate Micro- aluminum Serial thick- Rp 0.2 Rm A50 structure clad steel number ness (MPa) (MPa) (%) of matrix for substrate Embod- 2 mm 274 355 41 Equiaxed Interface iment 1 ferrite, is clean, the grain and no size of compound which is layer is 10-50 formed microns Embod-   2.4 mm 243 360 50 Equiaxed Interface iment 2 ferrite, is clean, the grain and no size of compound which is layer is 10-50 formed microns Embod-   2.8 mm 227 344 48 Equiaxed Interface iment 3 ferrite, is clean, the grain and no size of compound which is layer is 10-50 formed microns Embod- 3 mm 248 334 52 Equiaxed Interface iment 4 ferrite, is clean, the grain and no size of compound which is layer is 10-50 formed microns Embod-   3.5 mm 225 360 43 Equiaxed A small iment 5 ferrite, amount of the grain discontinuous size of compound which is layer, the 10-50 maximum microns thickness of which is 2.2 μm Embod- 4 mm 241 342 44 Equiaxed A small iment 6 ferrite, amount of the grain discontinuous size of compound which is layer, the 10-50 maximum microns thickness of which is 4 μm Embod- 6 mm 268 338 44 Equiaxed A small iment 7 ferrite, amount of the grain discontinuous size of compound which is layer, the 10-50 maximum microns thickness of which is 3.2 μm Embod- 8 mm 221 324 46 Equiaxed Interface iment 8 ferrite, is clean, the grain and no size of compound which is layer is 10-50 formed microns
It can be seen from Table 3 that the steel for the high-strength aluminum clad substrate of each embodiment of this application has stable yield strength. Under different rolling processes, steel plates of various specifications have yield strength of 210-290 MPa and tensile strength greater than or equal to 320 MPa and have extremely high elongation (the elongation is greater than or equal to 40%).

[0057] In addition, it can also be seen from Table 3 that the steel for the high-strength aluminum clad substrate of each embodiment of this application has excellent steel-aluminum interface bonding property, and the thickness of the steel-aluminum interface compound layer of the aluminum clad steel for the aluminum clad substrate is less than or equal to 5 μm. In some other preferred implementation modes, the thickness of the steel-aluminum interface compound layer can even be zero.

[0058] FIG. 1 illustrates a microstructure of steel for a high-strength aluminum clad substrate of Embodiment 1. As shown in FIG. 1, a matrix of the steel for the high-strength aluminum clad substrate of Embodiment 1 is an equiaxed ferrite, the grain size of which is 10-50 microns.

[0059] It can be seen from Table 1 to Table 3 and FIG. 1 that the steel for the high-strength aluminum clad substrate of each embodiment of this application adopts the extremely low C—Si—Mn design, supplemented by a small amount of Ti, N and O and appropriate P, so that the obtained steel for the high-strength aluminum clad substrate meets the requirements of high elongation, good steel-aluminum cladding property and high deformability of the aluminum clad substrate; and furthermore, the manufacturing method of this application has the advantages of short production period and simple process, and is very applicable to production of aluminum clad strip steel.

[0060] Compared with the prior art, the steel for the high-strength aluminum clad substrate and the manufacturing method therefor according to the present invention have the following advantages and beneficial effects: the steel for the high-strength aluminum clad substrate of the present invention has excellent comprehensive mechanical properties, with yield strength of 210-290 MPa, tensile strength greater than or equal to 320 MPa, and elongation exceeding 40%.

[0061] In addition, the steel for the high-strength aluminum clad substrate of the present invention has excellent steel-aluminum interface bonding property. The thickness of a steel-aluminum interface compound layer after the aluminum clad steel for the high-strength aluminum clad substrate is subjected to final high-temperature brazing is less than or equal to 5 μm. In some preferred implementation modes, the thickness can even be zero. Therefore, the steel-aluminum interface of the steel for the high-strength aluminum clad substrate of the present invention is clean, which is very suitable for the production of aluminum clad strip steel.

[0062] Furthermore, the mass percent of P in the steel for the high-strength aluminum clad substrate of the present invention is enlarged to 0.018-0.03%, which lowers the production difficulty, simplifies the production process and improves the production efficiency.

[0063] In addition, the steel for the high-strength aluminum clad substrate of the present invention has excellent plastic deformation capability, and can meet a single-pass large deformation requirement in an aluminum cladding rolling process, without annealing during the process, thereby reducing production procedures and improving the production efficiency.

[0064] In addition to the above-mentioned advantages and beneficial effects, the manufacturing method of the present invention is simple in process and lower in cost due to the adoption of high-temperature hot rolling, thus being very suitable for large-scale production of aluminum clad strip steel by enterprises.

[0065] It should be noted that the prior art part of the protection scope of the present invention is not limited to the embodiments provided in this application document, and all prior arts not contradicting the solution of the present invention, including but not limited to, the previous patent documents, prior publications, prior publications, etc., can be included in the protection scope of the present invention.

[0066] In addition, the combination of various technical features in this solution is not limited to the combination described in the claims of this application or the combination described in the specific embodiments. All technical features described herein can be freely combined or integrated in any way, unless contradictions arise between each other.

[0067] It should also be noted that the above-listed embodiments are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and subsequently made similar changes or modifications can be directly derived from or easily associated with the disclosure of the present invention by those skilled in the art, and should all fall within the protection scope of the present invention.