HIGH CORROSION-RESISTANCE STRIP STEEL AND MANUFACTURING METHOD THEREFOR

Abstract

Disclosed is a high corrosion-resistance strip steel, comprising a carbon steel base layer and a corrosion-resistance cladding layer roll-bonded with the carbon steel base layer, the corrosion-resistance cladding layer being austenitic stainless steel or pure titanium, the thickness of the corrosion-resistance cladding layer being 0.5% to 5% of the total thickness of the strip steel. In addition, further disclosed is a manufacturing method for the described high corrosion-resistance strip steel, comprising the steps of: (1) obtaining a base layer material and a cladding layer material; (2) assembling billets (3) pre-heating: pre-heating the billets at a temperature of 1150° C. to 1250° C., so that elements of the corrosion-resistance cladding layer and elements of the carbon steel base layer diffuse at the interface to form a stable transition layer, and then slowly cooling to room temperature; (4) secondary heating and rolling; and (5) water-cooling and then winding. The high corrosion-resistance strip steel finally provides, by means of rational component design, thickness design, and process design, the obtained steel plate or steel strip with a high corrosion-resistance surface and good interlayer bonding performance, and the steel plate or steel strip has good mechanical properties and processability.

Claims

1. A corrosion-resistant strip steel, comprising a carbon steel base layer and a corrosion-resistant cladding layer roll-bonded to the carbon steel base layer, wherein the corrosion-resistant cladding layer is austenitic stainless steel or pure titanium, and the corrosion-resistant cladding layer has a thickness that is 0.5-5% of a total thickness of the strip steel.

2. The corrosion-resistant strip steel according to claim 1, wherein the carbon steel base layer comprises the following chemical elements in mass percentage: C: 0.01-0.20%; Si: 0.10-0.5%; Mn: 0.5-2.0%; Al: 0.02-0.04%; Ti: 0.005-0.018%; Nb: 0.005-0.020%; and a balance of Fe and other unavoidable impurities.

3. The corrosion-resistant strip steel according to claim 2, wherein amounts of C, Si, Mn, Al, Ti and Nb meet at least one of: C: 0.01-0.18%; Si: 0.10-0.3%; Mn: 0.5-1.5%; Al: 0.02-0.03%; Ti: 0.005-0.015%; Nb: 0.005-0.015%.

4. The corrosion-resistant strip steel according to claim 1, further comprising at least one of the following chemical elements: 0<B≤0.0003%; 0<N≤0.006%; 0<Ni≤0.20%; 0<Cr≤0.20%; 0<Mo≤0.10%; 0<Sb≤0.30%; 0<V≤0.30%; 0<W≤0.30%; 0<Cu≤0.30%; 0<Sn≤0.30%; 0<Bi≤0.30%; 0<Se≤0.30%; 0<Te≤0.30%; 0<Ge≤0.30%; 0<As≤0.30%; 0<Ca≤0.30%; 0<Mg≤0.30%; 0<Zr≤0.30%; 0<Hf≤0.30%; 0<rare earth elements≤0.50%.

5. The corrosion-resistant strip steel according to claim 1, wherein among the other unavoidable impurities: P≤0.015%; and/or S≤0.010%.

6. The corrosion-resistant strip steel according to claim 1, wherein the carbon steel base layer in the corrosion-resistant strip steel comprises chemical elements in percentage by mass of: C: 0.01-0.20%; Si: 0.10-0.5%; Mn: 0.5-2.0%; Al: 0.02-0.04%; Ti: 0.005-0.018%; Nb: 0.005-0.020%; N: 0<N≤0.006%; Mo: ≤0.10%; Cr: ≤0.20%; Ni: ≤0.20%; and a balance of Fe and other unavoidable impurities.

7. The corrosion-resistant strip steel according to claim 1, wherein the carbon steel base layer has a microstructure of ferrite and pearlite, the austenitic stainless steel corrosion-resistant cladding layer has a microstructure of austenite, and a transition layer between the carbon steel base layer and the corrosion-resistant cladding layer is pearlite and ferrite.

8. The corrosion-resistant strip steel according to claim 1, wherein the corrosion-resistant strip steel has a tensile strength of ≥500 MPa, a yield strength of 370-510 MPa, and an elongation of ≥30%.

9. A manufacture method for the corrosion-resistant strip steel according to claim 1, comprising steps: (1) Providing a carbon steel base layer as a base material and a corrosion-resistant cladding layer as a cladding material; (2) Assembling a slab; (3) Pre-heating: pre-heating the slab at a temperature of 1150-1250° C. to diffuse elements of the corrosion-resistant cladding layer and the carbon steel base layer at an interface to form a stable transition layer, and then slowly cooling to room temperature; (4) Secondary heating and rolling: performing secondary heating at a temperature of 1100-1200° C., and then performing multi-pass rolling, wherein a finish rolling temperature is controlled to be not lower than 900° C.; and (5) Coiling after water cooling.

10. The manufacture method according to claim 8, wherein in the step (4), a total rolling reduction ratio is controlled to be not lower than 70%.

11. The manufacture method according to claim 8, wherein in the step (4), the finish rolling temperature is controlled to be 920-1000° C.

12. The manufacture method according to claim 8, wherein in the step (5), a coiling temperature is controlled to be 500-650° C.

13. The manufacture method according to claim 8, further comprising a surface treatment step or a cold rolling step after step (5).

14. The manufacture method according to claim 13, wherein the surface treatment step comprises acid pickling or mechanical descaling, and a cold rolling annealing temperature in the cold rolling step is controlled to be 600-750° C.

15. The manufacture method according to claim 8, wherein in step (1), each layer of cladding material has a thickness of 5-20 mm, and the base material has a thickness of 300-370 mm.

16. The manufacture method according to claim 9, wherein the carbon steel base layer comprises the following chemical elements in mass percentage: C: 0.01-0.20%; Si: 0.10-0.5%; Mn: 0.5-2.0%; Al: 0.02-0.04%; Ti: 0.005-0.018%; Nb: 0.005-0.020%; and a balance of Fe and other unavoidable impurities.

17. The manufacture method according to claim 16, wherein amounts of C, Si, Mn, Al, Ti and Nb meet at least one of: C: 0.01-0.18%; Si: 0.10-0.3%; Mn: 0.5-1.5%; Al: 0.02-0.03%; Ti: 0.005-0.015%; Nb: 0.005-0.015%.

18. The manufacture method according to claim 9, further comprising at least one of the following chemical elements: 0<B≤0.0003%; 0<N≤0.006%; 0<Ni≤0.20%; 0<Cr≤0.20%; 0<Mo≤0.10%; 0<Sb≤0.30%; 0<V≤0.30%; 0<W≤0.30%; 0<Cu≤0.30%; 0<Sn≤0.30%; 0<Bi≤0.30%; 0<Se≤0.30%; 0<Te≤0.30%; 0<Ge≤0.30%; 0<As≤0.30%; 0<Ca≤0.30%; 0<Mg≤0.30%; 0<Zr≤0.30%; 0<Hf≤0.30%; 0<rare earth elements≤0.50%.

19. The manufacture method according to claim 9, wherein the carbon steel base layer in the corrosion-resistant strip steel comprises chemical elements in percentage by mass of: C: 0.01-0.20%; Si: 0.10-0.5%; Mn: 0.5-2.0%; Al: 0.02-0.04%; Ti: 0.005-0.018%; Nb: 0.005-0.020%; N: 0<N≤0.006%; Mo: ≤0.10%; Cr: ≤0.20%; Ni: ≤0.20%; and a balance of Fe and other unavoidable impurities.

20. The manufacture method according to claim 9, wherein the carbon steel base layer has a microstructure of ferrite and pearlite, the austenitic stainless steel corrosion-resistant cladding layer has a microstructure of austenite, and a transition layer between the carbon steel base layer and the corrosion-resistant cladding layer is pearlite and ferrite; and wherein the corrosion-resistant strip steel has a tensile strength of ≥500 MPa, a yield strength of 370-510 MPa, and an elongation of ≥30%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] FIG. 1 schematically shows the structure of the high-corrosion-resistant strip steel according to the present disclosure in some embodiments.

[0069] FIG. 2 schematically shows the structure of the high-corrosion-resistant strip steel according to the present disclosure in some other embodiments.

[0070] FIG. 3 is a photograph showing a typical tissue at the upper surface of the high corrosion resistant strip steel in Example 1.

[0071] FIG. 4 is a photograph showing a typical tissue at the lower surface of the high corrosion resistant strip steel in Example 1.

[0072] FIG. 5 is a photograph showing a typical tissue of the high corrosion resistant strip steel in Example 2.

[0073] FIG. 6 is a photograph showing a typical tissue of the high corrosion resistant strip steel in Example 6.

DETAILED DESCRIPTION

[0074] The high corrosion resistant strip steel according to the present disclosure and the method for manufacturing the same will be further explained and illustrated with reference to the accompanying drawing of the specification and the specific examples. Nonetheless, the explanation and illustration are not intended to unduly limit the technical solution of the present disclosure.

Examples 1-6

[0075] The following steps were employed to prepare the high corrosion resistant strip steel in Examples 1-6:

[0076] (1) Providing a base material and a cladding material. The chemical compositions of the base material and the cladding material are listed in Table 1.

[0077] (2) Assembling a slab: When the slab was assembled, the thickness of the high-corrosion-resistant strip steel was 0.5%-5% of the total thickness of the slab. In some embodiments, prior to the assembling, the base material and the cladding material were pre-treated. Then, the faying surfaces of the base material and the cladding material were sealed by welding around the periphery, and the joined surfaces were vacuumized after the sealing by welding.

[0078] (3) Pre-heating: The slab was pre-heated at a temperature of 1150-1250° C. to diffuse elements of the corrosion-resistant cladding layer and the carbon steel base layer at the interface to form a stable transition layer, and then slowly cooled to room temperature.

[0079] (4) Secondary heating and rolling: Secondary heating was performed at a temperature of 1100-1200° C., and then multi-pass rolling was performed. The finish rolling temperature was controlled to be not lower than 900° C.

[0080] (5) Coiling after water cooling.

[0081] In some embodiments, in step (4), the total rolling reduction ratio was not lower than 70%.

[0082] In some embodiments, in step (4), the finish rolling temperature was controlled to be 920-1000° C.

[0083] In some embodiments, in step (5), the coiling temperature was controlled to be 500-650° C.

[0084] It should be noted that, in some embodiments, after step (5), the hot-rolled high-corrosion-resistant strip steel coil was subjected to surface treatment, including acid pickling or mechanical descaling.

[0085] In some other embodiments, after step (5), cold rolling annealing was also performed to obtain a cold-rolled high-corrosion-resistant strip steel coil.

[0086] Table 1 lists the mass percentages of the various chemical elements in the high-corrosion-resistant strip steel of Examples 1-6.

TABLE-US-00001 TABLE 1 (wt %, the balance is Fe and other unavoidable impurities except for P and S) Corrosion resistant Other cladding layer preferably Carbon steel addible Ex. base layer C Si Mn P S Al Ti Nb elements N 1 Corrosion resistant 304L used for the corrosion resistant cladding layer, meeting cladding layer GB/T 20878-2007 or the corresponding standards in other countries Carbon steel 0.10 0.35 1.50 0.010 0.005 0.040 0.018 0.020 Mo: 0.10 0.0045 base layer 2 Corrosion resistant 304 used for the corrosion resistant cladding layer, meeting cladding layer GB/T 20878-2007 or the corresponding standards in other countries Carbon steel 0.14 0.25 1.00 0.010 0.005 0.030 0.014 0.011 Cr: 0.20 0.0052 base layer 3 Corrosion resistant 316L used for the corrosion resistant cladding layer, meeting cladding layer GB/T 20878-2007 or the corresponding standards in other countries Carbon steel 0.20 0.15 0.50 0.008 0.004 0.020 0.005 0.005 — 0.0040 base layer 4 Corrosion resistant 316 used for the corrosion resistant cladding layer, meeting cladding layer GB/T 20878-2007 or the corresponding standards in other countries Carbon steel 0.11 0.30 1.48 0.008 0.005 0.026 0.008 0.005 Ni: 0.10 0.0038 base layer 5 Corrosion resistant 316 used for the corrosion resistant cladding layer, meeting cladding layer GB/T 20878-2007 or the corresponding standards in other countries Carbon steel 0.14 0.25 0.5  0.010 0.005 0.030 0.014 0.011 Cr: 0.20 0.0052 base layer 6 Corrosion resistant TA2 used for the corrosion resistant cladding layer, meeting cladding layer GB/T 3621-2007 or the corresponding standards in other countries Carbon steel 0.10 0.35 1.50 0.010 0.005 0.040 0.018 0.020 Mo: 0.10 0.0045 base layer

[0087] Table 2 lists the specific process parameters for the high-corrosion-resistant strip steel of Examples 1-6.

TABLE-US-00002 TABLE 2 Thickness of each Total slab layer of thickness Final cladding after Pre-heating Heating Final rolling product material assembling temperature/ temperature/ temperature/ Ex. type Assembly (mm) (mm) ° C. ° C. ° C. 1 Cold-rolled Cladding layer + 8 380 1160 1150 980 plate base layer + cladding layer 2 Hot-rolled Cladding layer + 8 325 1250 1160 1000 plate base layer 3 Cold-rolled Cladding layer + 10 380 1180 1140 990 plate base layer + cladding layer 4 Cold-rolled Cladding layer + 8 380 1200 1180 980 plate base layer + cladding layer 5 Hot-rolled Cladding layer + 8 325 1200 1160 1000 plate base layer 6 Cold-rolled Cladding layer + 15 380 1150 1150 920 plate base layer + cladding layer Thickness of Thickness of corrosion corrosion Hot-rolled resistant Cold rolling Cold-rolled resistant Coiling plate cladding layer annealing plate cladding layer temperature/ thickness/ of hot-rolled temperature/ thickness/ of cold-rolled Ex. ° C. mm plate/μm ° C. mm plate/μm 1 600 4 50 700 1 12 2 650 3.5 40 — — — 3 550 4 70 750 2 20 4 600 4 50 700 1 12 5 640 3.5 40 — — — 6 550 2 80 600   0.5 20

[0088] In order to verify the implementation effects of the present disclosure and prove the excellent effects of the present disclosure over the prior art, Examples 1-6 of the high-corrosion-resistant strip steel in the present disclosure were tested. The test results are listed in Table 3.

TABLE-US-00003 TABLE 3 Yield strength Tensile Structure (carbon steel base layer + transition Ex. (MPa) strength (MPa) Elongation (%) layer + corrosion-resistant layer) 1 472 611 35.8 carbon steel base layer: ferrite + pearlite transition layer: ferrite + pearlite corrosion-resistant layer: austenite 2 507 649 36.0 carbon steel base layer: ferrite + pearlite transition layer: ferrite + pearlite corrosion-resistant layer: austenite 3 480 650 40.0 carbon steel base layer: ferrite + pearlite transition layer: ferrite + pearlite corrosion-resistant layer: austenite 4 482 638 38.0 carbon steel base layer: ferrite + pearlite transition layer: ferrite + pearlite corrosion-resistant layer: austenite 5 482 635 39.0 carbon steel base layer: ferrite + pearlite transition layer: ferrite + pearlite corrosion-resistant layer: austenite 6 382 535 30.0 carbon steel base layer: ferrite + pearlite transition layer: ferrite + pearlite corrosion-resistant layer: α-Ti

[0089] FIG. 1 schematically shows the structure of the high-corrosion-resistant strip steel according to the present disclosure in some embodiments.

[0090] As shown in FIG. 1, in these embodiments, the high-corrosion-resistant strip steel comprises a carbon steel base layer 1 and corrosion-resistant cladding layers 2 roll-bonded to the upper and lower surfaces of the carbon steel base layer 1. The corrosion-resistant cladding layers 2 may be austenitic stainless steel or pure titanium, and the thickness of the corrosion-resistant cladding layers is 0.5-5% of the total thickness of the strip steel.

[0091] FIG. 2 schematically shows the structure of the high-corrosion-resistant strip steel according to the present disclosure in some other embodiments.

[0092] As shown in FIG. 2, in these embodiments, the high-corrosion-resistant strip steel comprises a carbon steel base layer 1 and a corrosion-resistant cladding layer 2 roll-bonded to the upper surface of the carbon steel base layer 1 (of course, in some other embodiments, a corrosion-resistant cladding layer 2 may also be roll-bonded to the lower surface of the carbon steel base layer 1). The corrosion-resistant cladding layer 2 may be austenitic stainless steel or pure titanium, and the thickness of the corrosion-resistant cladding layer is 0.5-5% of the total thickness of the strip steel.

[0093] FIG. 3 is a photograph showing a typical tissue at the top surface of the high corrosion resistant strip steel in Example 1. FIG. 4 is a photograph showing a typical tissue at the lower surface of the high corrosion resistant strip steel in Example 1.

[0094] As can be seen from FIG. 3 and FIG. 4, in the high-corrosion-resistant strip steel of Example 1, the microstructure of the carbon steel base layer 1 is ferrite and pearlite. The corrosion-resistant cladding layer 2 is an austenitic stainless steel corrosion-resistant cladding layer, and the microstructure of the corrosion-resistant cladding layer 2 is austenite. The transition layer between the carbon steel base layer 1 and the corrosion-resistant cladding layer 2 is ferrite and pearlite.

[0095] FIG. 5 is a photograph showing a typical tissue of the high corrosion resistant strip steel in Example 2.

[0096] As can be seen from FIG. 5, in the high-corrosion-resistant strip steel of Example 2, the microstructure of the carbon steel base layer 1 is ferrite and pearlite. The corrosion-resistant cladding layer 2 is an austenitic stainless steel corrosion-resistant cladding layer, and the microstructure of the corrosion-resistant cladding layer 2 is austenite. The transition layer between the carbon steel base layer 1 and the corrosion-resistant cladding layer 2 is ferrite and pearlite. It should be noted that, as can be seen from FIG. 5, the thickness of the high-corrosion-resistant strip steel of Example 2 is 3.5 mm, and the thickness of the corrosion-resistant cladding layer 2 is 40

[0097] FIG. 6 is a photograph showing a typical tissue of the high corrosion resistant strip steel in Example 6.

[0098] As can be seen from FIG. 6, in the high-corrosion-resistant strip steel of Example 6, the microstructure of the carbon steel base layer 1 is ferrite and pearlite. The corrosion-resistant cladding layer 2 is a pure titanium corrosion-resistant cladding layer, and its microstructure is α-Ti. The transition layer between the carbon steel base layer 1 and the corrosion-resistant cladding layer 2 is ferrite and pearlite. The thickness of the high-corrosion-resistant strip steel of Example 6 is 0.5 mm, and the thickness of each corrosion-resistant cladding layer 2 is 20 μm.

[0099] To sum up, high-corrosion-resistant strip steel according to the present disclosure is provided with a corrosion-resistant cladding layer and a carbon steel base layer having proper thicknesses, so that a strip having high corrosion resistance and good mechanical properties is obtained.

[0100] In some embodiments, a transition layer structure of a certain thickness is formed between the corrosion-resistant cladding layer and the carbon steel base layer, so that complete metallurgical bonding of the corrosion-resistant cladding layer and the carbon steel base layer is achieved extremely well. While the corrosion resistance and the mechanical properties are guaranteed, the applicability and economy of the material are promoted. The essential sore point with the existing carbon steel materials can be addressed. The corrosion resistance, bonding strength and durability achieved according to the present disclosure are not possible for the existing coated plate products. The high-corrosion-resistant strip steel according to the present disclosure is more energy-saving, environment-friendly and maintenance-free, and has important significance and promising prospects.

[0101] In addition, the manufacturing method according to the present disclosure also has the above advantages and beneficial effects.

[0102] 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 disclosure file. All the prior art contents not contradictory to the technical solution of the present disclosure, including but not limited to prior patent literature, prior publications, prior public uses and the like, may all be incorporated into the protection scope of the present disclosure.

[0103] 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.

[0104] 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.