MULTI-LAYER ROLLED COMPOSITE BOARD AND MANUFACTURING METHOD THEREFOR

Abstract

Disclosed is a multi-layer rolled composite board, comprising a transition layer provided between two adjacent composite layers, wherein the transition layer is an anisotropic steel sheet. Also disclosed is a manufacturing method for the multi-layer rolled composite board, the method comprising the following steps: (1) providing a transition layer between adjacent composite layers to assemble a blank, and creating a vacuum between the layers; and (2) performing composite rolling, comprising: heating the blank to 1100-1260° C. and maintaining the temperature for 0.6 h or above, then performing hot rolling at a temperature of Ar3 or above, with the final rolling temperature being controlled to be higher than 820° C., cooling at a speed of 30-100° C./s after rolling, and then coiling, with the coiling temperature being controlled to be 20-750° C. The multi-layer rolled composite board of the present invention can be greatly transformed according to different compositions and processes so as to achieve different strength grades ranging from 150 MPa to 1700 MPa, thereby providing the basis for different specific mechanical properties for the whole steel sheet.

Claims

1. A multilayer rolled clad plate, characterized in that it comprises a transition layer between two adjacent cladding layers, wherein the transition layer is an anisotropic thin steel plate.

2. The multilayer rolled clad plate according to claim 1, wherein the anisotropic thin steel plate is a cold rolled steel plate or a hot rolled acid-pickled steel plate.

3. The multilayer rolled clad plate according to claim 1, wherein the anisotropic thin steel plate has an orientation degree that satisfies: 1.25≥AI≥1.05 before assembling a blank.

4. The multilayer rolled clad plate according to claim 1, wherein the transition layer comprises one or more layers.

5. The multilayer rolled clad plate according to claim 1, wherein the thickness of each layer of the anisotropic thin steel plate is less than 5% of the total thickness of the multilayer rolled clad plate.

6. The multilayer rolled clad plate according to claim 1, wherein the multilayer rolled clad plate comprises a substrate layer, a transition layer located on one or both sides of the substrate layer, and a cladding material layer located on the outside of the transition layer, wherein the thickness of the substrate layer is 0.5-4.0 mm and the thickness of each cladding material layer is in the range of 0.05-0.4 mm.

7. The multilayer rolled clad plate according to claim 1, wherein the multilayer rolled clad plate has a metallic or non-metallic plating layer on at least one surface.

8. The multilayer rolled clad plate according to claim 1, wherein the anisotropic thin steel plate comprises the following chemical elements in weight percentages: C: 0.01-0.10%; Si: 0.01-0.5%; Mn: 0.5-2.5%; Al: 0.01-0.06%; Ti≤0.06%; Cr≤0.50%; Mo≤0.30%; and a balance of Fe and unavoidable impurities.

9. The multilayer rolled clad plate according to claim 1, wherein the anisotropic thin steel plate comprises a substrate layer, a transition layer and a cladding material layer, wherein the C content of the transition layer is between that of the substrate layer and the cladding material layer.

10. A manufacturing method for the multilayer rolled clad plate according to claim 1, wherein the manufacturing method comprises the following steps: (1) providing a transition layer between adjacent cladding layers for assembling a blank, and vacuumizing between layers; (2) clad rolling: wherein the blank is heated to 1100-1260° C. and held for 0.5 hours or more, then hot-rolled at a temperature of Ar3 or more, wherein a final rolling temperature is controlled to be greater than 820° C., and after rolling, the blank is cooled at a rate of 30-100° C./s, and then coiled, and wherein the coiling temperature is controlled to be 20-750° C.

11. The manufacturing method according to claim 10, wherein the method further comprises Step (3) of cold rolling.

12. The manufacturing method according to claim 11, wherein the method further comprises Step (4) of annealing: wherein the plate is soaked at a soaking temperature of 700-880° C., and then cooled at a rate of 3-20° C./s to a rapid cooling starting temperature of 600-780° C., and then cooled at a rate of 20-1000° C./s to 150-550° C.

13. The manufacturing method according to claim 12, wherein the method further comprises Step (5) of tempering: wherein a tempering temperature is 150-550° C., and a tempering time is 100 s-400 s.

14. The manufacturing method according to claim 10, wherein the method further comprises a step of leveling.

15. The multilayer rolled clad plate according to claim 1, wherein the thickness of each layer of the anisotropic thin steel plate is 0.5 to 10.0 mm.

16. The manufacturing method according to claim 10, wherein the anisotropic thin steel plate is a cold rolled steel plate or a hot rolled acid-pickled steel plate.

17. The manufacturing method according to claim 10, wherein the anisotropic thin steel plate has an orientation degree that satisfies: 1.25≥Al≥1.05 before assembling a blank; or the thickness of each layer of the anisotropic thin steel plate is less than 5% of the total thickness of the multilayer rolled clad plate; or the anisotropic thin steel plate comprises the following chemical elements in weight percentages: C: 0.01-0.10%; Si: 0.01-0.5%; Mn: 0.5-2.5%; Al: 0.01-0.06%; Ti≤0.06%; Cr≤0.50%; Mo≤0.30%; and a balance of Fe and unavoidable impurities; or the anisotropic thin steel plate comprises a substrate layer, a transition layer and a cladding material layer, wherein the C content of the transition layer is between that of the substrate layer and the cladding material layer.

18. The manufacturing method according to claim 10, wherein the transition layer comprises one or more layers.

19. The manufacturing method according to claim 10, wherein the multilayer rolled clad plate comprises a substrate layer, a transition layer located on one or both sides of the substrate layer, and a cladding material layer located on the outside of the transition layer, wherein the thickness of the substrate layer is 0.5-4.0 mm and the thickness of each cladding material layer is in the range of 0.05-0.4 mm; or the multilayer rolled clad plate has a metallic or non-metallic plating layer on at least one surface.

20. The manufacturing method according to claim 10, wherein the thickness of each layer of the anisotropic thin steel plate is 1 to 3 mm.

Description

DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 shows the structure of a comparative clad plate according to Comparative Example 1;

[0034] FIG. 2 shows the structure of a multilayer rolled clad plate according to Example 1;

[0035] FIG. 3 is a photograph showing a microscopic metallographic structure of the comparative clad plate according to Comparative Example 1;

[0036] FIG. 4 is a photograph showing a microscopic metallographic structure of the multilayer rolled clad plate according to Example 1.

DETAILED DESCRIPTION

[0037] The present disclosure will be further described with reference to the accompanying drawings of the specification and specific embodiments of the multilayer rolled clad plate according to the present disclosure and the manufacturing method thereof to make a further explanation and description, however, the explanation and description does not constitute an improper limitation of the technical solution of the present disclosure.

Examples 1-6 and Comparative Example 1

[0038] The multilayer rolled clad plate of Example 1-6 was prepared by the following steps:

[0039] (1) providing a transition layer between adjacent cladding layers for assembling a blank, and vacuumizing between layers, wherein the mass percentage of each blank layer is shown in Table 1. It should be noted that the cladding layer in the present disclosure includes a substrate layer and a cladding material layer.

[0040] (2) clad rolling: the blank is heated to 1100-1260° C. and held for 0.5 hours or more, preferably 0.6 hours or more; wherein the final rolling temperature is controlled to be greater than 820° C., and after rolling, the blank was cooled at a rate of 30-100° C./s, and then coiled, and the coiling temperature was controlled to be 20-750° C.

[0041] In some embodiments, the manufacturing method further comprised the step (3) of cold rolling.

[0042] In further embodiments, the manufacturing method further comprised the step (4) of annealing: wherein the plate was soaked at a soaking temperature of 700-880° C., and then cooled at a rate of 3-20° C./s to a rapid cooling starting temperature of 600-780° C., preferably 600-770° C., and then cooled at a rate of 20-1000° C./s, preferably 40-1000° C./s to 150-550° C.

[0043] In some other embodiments, the manufacturing method further comprised the step (5) of tempering: wherein the tempering temperature was 150-550° C., and the tempering time was 100 s-400 s.

[0044] In some other embodiments, the manufacturing method further comprised the step of leveling.

[0045] The mass percentages of each chemical element of the multilayer rolled clad plate of Example 1-6 and the comparative clad plate of Comparative Example 1 are shown in Table 1.

TABLE-US-00001 TABLE 1 (wt %, with a balance of Fe and other unavoidable impurities) Chemical elements of blank layer C Si Mn Al B Ti Cr Mo AI Example 1 Substrate layer 0.241 0.226 1.258 0.0448 0.0028 0.025 0.14 — — Cladding material layer 0.0013 0.005 0.143 0.0255 — 0.022 — — — Transition layer 0.066 0.064 1.358 0.0375 —  0.0439 — — 1.15 Example 2 Substrate layer 0.288 0.32 1.67 0.0331 0.0028 0.021 — — — Cladding material layer 0.0021 0.004 0.152 0.0211 — — — — — Transition layer 0.083 0.052 1.134 0.0231 — 0.012 — — 1.07 Example 3 Substrate layer 0.0011 0.004 0.312 0.0211 — — — — — Cladding material layer 0.098 0.26 2.28 0.0249 — 0.021 0.55 0.22 — Transition layer 0.034 0.045 1.344 0.0224 — — — — 1.23 Example 4 Substrate layer 0.188 1.71 2.72 0.0321 0.012 — Cladding material layer 0.0017 0.005 0.153 0.032  0.0309 — Transition layer 0.055 0.34 1.23 0.0229 1.17 Example 5 Substrate layer 0.172 1.55 1.82 0.0324 0.015  0.211 — Cladding material layer 0.027 0.03 0.342 0.0112 — Transition layer 0.034 0.12 1.13 0.0223 1.10 Example 6 Substrate layer 0.068 0.226 1.358 0.0334  0.0939 — Cladding material layer 0.223 0.126 1.325 0.216 0.0023  0.098 — Transition layer 0.098 0.23 2.21 0.0298 0.019  0.481 0.21 1.16 Chemical elements of blank layer C Si Mn Al B Ti Cr Mo — Comparative Substrate layer 0.241 0.226 1.258 0.0448 0.0028 0.025 0.14 — — Example 1 Cladding material layer 0.0013 0.005 0.143 0.0255 — 0.022 — — —

[0046] The specific process parameters of the multilayer rolled clad plate of Example 1-6 and the comparative clad plate of Comparative Example 1 are shown in Table 2.

TABLE-US-00002 TABLE 2 Example Example Example Example Example Example Comparative 1 2 3 4 5 6 Example 1 Step Number of blank 5 5 5 5 5 5 — (1) layers Thickness ratio of 20:1.5:180:1.5:20 22:2:182:2:22 20:1:180:1:20 20:1.5:182:1.5:20 25:2:170:2:25 18:2:190:2:18 — blank layers * Step Heating 1260 1100 1150 1180 1200 1230 1260 (2) temperature, ° C. Holding time, h 1 1.5 0.5 1 1.2 1.8 1 Final rolling 880 840 890 880 870 900 880 temperature, ° C. Cooling rate, ° C. 50 100 60 70 100 80 50 Coiling 650 500 750 400 50 200 650 temperature, ° C. Step Cold rolled reduction 50 60 40 45 — 70 50 (3) rate, % Step Annealing 840 880 700 850 — 720 840 (4) temperature, ° C. Cooling rate, ° C./s 5 3 20 10 — 5 5 Rapid cooling starting 750 780 600 710 — 650 750 temperature, ° C. Rapid cooling 750 1000 30 70 — 20 750 rate, ° C./s Final cooling 200 150 550 200 — 240 200 temperature, ° C. Step Tempering 200 150 550 410 — 240 200 (5) temperature, ° C. Tempering time, s 280 400 180 240 — 100 280 *: each blank layer comprises a cladding material layer: a transition layer: a substrate layer: a transition layer: a cladding material layer in sequence, and the thickness unit is mm.

[0047] The relevant performance parameters of the multilayer rolled clad plate of Example 1-6 and its advantages after cladding are shown in Table 3.

TABLE-US-00003 TABLE 3 Tensile Yield strength strength Elongation No. (MPa) (MPa) (%) Advantage after cladding Example 1 1510 1208 8.3 Mild steel cladding layer + martensitic steel substrate layer is adopted, so that the steel plate after cladding is a 1500 MPa high strength steel, which has excellent bend processing performance Example 2 1728 1401 6.8 Mild steel cladding layer + martensitic steel substrate layer is adopted, so that the steel plate after cladding is a 1700 MPa high strength steel, which has excellent bend processing performance. Example 3 118 184 25.2 High strength steel cladding layer + mild steel substrate layer is adopted, so that the steel plate after cladding is a mild steel for stamping, which has excellent pick resistance. Example 4 911 1282 16.6 Mild steel cladding layer + high strength steel substrate layer is adopted, so that the steel plate after cladding is a high-strength cold-rolled QP steel with a high Si content, which has good pick resistance of surface coating. Example 5 778 1082 21.4 Mild steel cladding layer + high strength steel substrate layer enables the steel plate after cladding to be a high-strength hot-rolled QP steel with a high Si content, which has good surface quality Example 6 804 871 9.6 Martensitic steel cladding layer + high precipitation strengthened steel substrate layer is adopted, so that the steel plate after cladding can avoid the problem of decarburizing the surface of the precipitation reinforced steel and affecting the surface hardness.

[0048] FIG. 1 shows the structure of the comparative clad plate according to Comparative Example 1.

[0049] FIG. 2 shows the structure of the multilayer rolled clad plate according to Example 1.

[0050] According to FIG. 1 and FIG. 2, it can be seen that compared to the comparative clad plate comprising the structure of only three layers (including a substrate layer 2 and two cladding material layers 1 cladded with the substrate layer 2), the multilayer rolled clad plate of Example 1 according to the present disclosure has a transition layer 3 between the cladding material layer 1 and the substrate layer 2, and the transition layer 3 is an anisotropic thin steel plate.

[0051] It should be noted that, in some other embodiments, the transition layer 3 may also have multiple layers.

[0052] The anisotropic thin steel plate of the transition layer 3 is a cold-rolled steel plate or a hot-rolled acid-pickled steel plate, and the orientation degree before assembling a blank satisfies 1.25≥AI≥1.05, and the thickness of the anisotropic thin steel plate in each layer is less than 5% of the total thickness of the multilayer rolled clad plate.

[0053] In some other embodiments, there is a metallic or non-metallic plating layer on at least one surface of the multilayer rolled clad plate.

[0054] FIG. 3 is a photograph showing a microscopic metallographic structure of the comparative clad plate according to Comparative Example 1;

[0055] FIG. 4 is a photograph showing a microscopic metallographic structure of the multilayer rolled clad plate according to Example 1.

[0056] According to FIG. 3 and FIG. 4, it can be seen that compared to the comparative clad plate of Comparative Example 1, the multilayer rolled clad plate of Example 1 has significantly improved C diffusion between the cladding material layer 1 and the substrate layer 2. This is because that the C content plays a critical role in strength. The diffusion of C atoms belongs to gap diffusion with a high diffusion rate, especially when there is a large carbon potential difference between both sides of the clad interface, C atom is very easy to diffuse, in serious cases even the respective properties of the substrate layer 2 and the cladding material layer 1 are effected. Serious C diffusion leads to a decrease in the strength of the substrate layer and in the toughness of the cladding layer. The anisotropic thin steel plate having a C content between the substrate layer 2 and the cladding material layer 1 is selected as the transition layer 3, which can effectively reduce the carbon potential difference between two sides of the clad interface and greatly slow down the C diffusion.

[0057] The thickness of the transition layer 3 should be relatively thin, this is because if the thickness of the transition layer 3 is thick, the bonding strength after roll cladding depends on the material strength of the transition layer 3 and low strength of the transition layer 3 will reduce the bonding performance of the metal clad plate. If the thickness of the transition layer 3 is too thin, it does not play a role in preventing the diffusion of elements.

[0058] As can be seen from FIG. 4, the bonding performance of the clad interface of Example 1 in the present disclosure is better.

[0059] Based on the above, the multilayer clad plate of the present disclosure can vary greatly according to different compositions and processes, and can achieve different strength grades from 100 MPa to 1700 MPa, providing different specific mechanical properties for the overall steel plate.

[0060] In addition, the manufacturing method according to the present disclosure also has the above advantages and beneficial effects.

[0061] It's to be noted that the prior art portions in the protection scope of the present disclosure are not limited to the examples set forth in the present application document. All the prior art contents not contradictory to the technical solution of the present disclosure, including but not limited to prior patent literatures, prior publications, prior public uses and the like, may all be incorporated into the protection scope of the present disclosure.

[0062] In addition, the ways in which the various technical features of the present disclosure are combined are not limited to the ways recited in the claims of the present disclosure or the ways described in the specific examples. All the technical features recited in the present disclosure may be combined or integrated freely in any manner, unless contradictions are resulted.

[0063] It should also be noted that the examples set forth above are only specific examples according to the present disclosure. Obviously, the present disclosure is not limited to the above examples. Similar variations or modifications made thereto can be directly derived or easily contemplated from the present disclosure by those skilled in the art. They all fall in the protection scope of the present disclosure.