# US 12,109,776 B2 · High corrosion-resistance strip steel and manufacturing method therefor

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- Number: US 12,109,776 B2
- Document ID: US12109776B2
- Status: Granted
- Kind: B2
- Application number: 17/790,590
- Filed: 2021-01-12
- Published: 2022-12-15
- Granted: 2024-10-08
- Earliest claimed: 2020-01-13
- Assignees: Baoshan Iron & Steel Co., Ltd.
- Applicants: Baoshan Iron & Steel Co., Ltd.
- Inventors: Bo Yan; Sihai Jiao
- Web page: https://patentgrep.com/patent/US12109776B2

## CPC

- B32B 15/011: {all layers being formed of iron alloys or steels}
- B21B 1/22: for rolling {plates, strips,} bands or sheets of indefinite length (B21B1/42 takes precedence)
- B23K 31/02: relating to soldering or welding
- B32B 15/013: {one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium}
- C21D 1/02: Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
- C21D 1/19: by interrupted quenching
- C21D 1/60: Aqueous agents
- C21D 6/004: {containing Cr and Ni}
- C21D 8/0226: {Hot rolling}
- C21D 8/0263: {following hot rolling}
- C21D 8/0273: {Final recrystallisation annealing}
- C21D 9/46: for sheet metals
- C22C 14/00: Alloys based on titanium
- C22C 38/001: {containing N}
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C22C 38/08: containing nickel {(C22C38/105 takes precedence)}
- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- C22C 38/14: containing titanium or zirconium
- C22C 38/26: with niobium or tantalum
- C22C 38/28: with titanium or zirconium
- C22C 38/60: containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
- B23K 2101/18: Sheet panels
- B23K 2101/34: Coated articles {; Surface treated articles}
- B23K 2103/04: Steel {or steel} alloys
- B23K 2103/05: {Stainless steel}
- B23K 2103/14: Titanium or alloys thereof
- B23K 2103/18: Dissimilar materials
- B32B 2250/02: 2 layers
- B32B 2307/732: Dimensional properties
- B32B 2311/18: Titanium
- B32B 2311/30: Iron, e.g. steel
- C21D 2211/001: Austenite
- C21D 2211/005: Ferrite
- C21D 2211/009: Pearlite
- C21D 2251/02: Clad material
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B21B: ROLLING OF METAL (auxiliary operations used in connection with metal-working operations covered in B21, see B21C; bending by rolling B21D; manufacture of particular objects, e.g. screws, wheels, rings, barrels, balls, by rolling B21H; pressure welding by means of a rolling mill B23K20/04)
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

Disclosed is a high corrosion-resistance strip steel and its manufacturing method. The high corrosion-resistance strip steel comprises 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. The high corrosion-resistance strip steel has a high corrosion-resistance surface, good interlayer bonding performance, good mechanical properties and processability.

## Claims

### Claim 1

A corrosion-resistant cold-rolled strip steel, comprising a carbon steel base layer, a corrosion-resistant cladding layer roll-bonded to the carbon steel base layer, and a transition layer between the carbon steel base layer and the corrosion-resistant cladding layer, 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 unavoidable impurities, 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, and wherein the carbon steel base layer has a microstructure of ferrite and pearlite, the austenitic stainless steel has a microstructure of austenite, and the transition layer has a microstructure of pearlite and ferrite, and wherein the thickness of the cold-rolled strip is 0.5-2 mm and the thickness of the corrosion-resistant cladding layer is 12-20 μm.

### Claim 2 (depends on 1)

The corrosion-resistant cold-rolled strip steel according to claim 1, 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%.

### Claim 3 (depends on 1)

The corrosion-resistant cold-rolled 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%.

### Claim 4 (depends on 1)

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

### Claim 5 (depends on 1)

The corrosion-resistant cold-rolled 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 unavoidable impurities.

### Claim 6 (depends on 1)

The corrosion-resistant cold-rolled 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%.

### Claim 7 (depends on 1)

A manufacture method for the corrosion-resistant cold-rolled 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.

### Claim 8 (depends on 7)

The manufacture method according to claim 7, wherein in the step (4), a total rolling reduction ratio is controlled to be not lower than 70%.

### Claim 9 (depends on 7)

The manufacture method according to claim 7, wherein in the step (4), the finish rolling temperature is controlled to be 920-1000° C.

### Claim 10 (depends on 7)

The manufacture method according to claim 7, wherein in the step (5), a coiling temperature is controlled to be 500-650° C.

### Claim 11 (depends on 7)

The manufacture method according to claim 7, further comprising a surface treatment step or a cold rolling step after step (5).

### Claim 12 (depends on 11)

The manufacture method according to claim 11, 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.

### Claim 13 (depends on 7)

The manufacture method according to claim 7, 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.

### Claim 14 (depends on 7)

The manufacture method according to claim 7, 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%.

### Claim 15 (depends on 7)

The manufacture method according to claim 7, 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%.

### Claim 16 (depends on 7)

The manufacture method according to claim 7, 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.

### Claim 17 (depends on 7)

The manufacture method according to claim 7, 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%.