Device and method for manufacturing metal clad strips continuously

Abstract

The device and method for manufacturing metal clad strip continuously provided by the present invention, combines casting, rolling and heat treatment used for the single material manufacture with the continuous and large-scale manufacture method for the clad strip, greatly improves the productivity of clad strip. The present invention can be used for manufacturing single-sided or double-sided clad strips with different thickness specifications, wherein the base layer material or the clad layer material can be selected in a wide range, including carbon steel, stainless steel, special alloy steel, titanium, copper and the like. In the present application, continuous casting and rolling clad strip is implemented, which decrease the energy consumption and costs.

Claims

1. A device comprising: base material supplying equipment including a decoiler, a pinch roll, a shot blasting machine, a welding equipment, a welding pinch roll, an induction heating apparatus, and a guiding roll; a mold, wherein the base material supplying equipment is configured to transport a base material strip through the decoiler, the pinch roll, the shot blasting machine, the welding equipment, the welding pinch roll, the induction heating apparatus, and the guiding roll to the mold, the mold is configured to merge the base material strip and molten steel, the base material strip enters the mold along a middle interior of the mold from above and passes through the mold, and two inner walls of the mold are sealed with side seal plates; two tundishes configured to cast molten steel, wherein the two tundishes are provided above the mold, the molten steel flows from the two tundishes into the mold and makes contact with two sides of the base material strip in the mold so that a preliminary melt merging takes place in which the base material strip forms a clad slab that passes through the mold from below; a secondary cooling section configured to cool the clad slab by a cooling-spray located at an outlet of a lower part of the mold; a leveling roll provided after the secondary cooling section; a rolling mill provided after the leveling roll and configured to roll the clad slab into a clad strip; an on-line cooling equipment for the clad strip, wherein the on-line cooling equipment is provided after the rolling mill; a straightening machine provided at an exit of the on-line cooling equipment and configured to straighten the clad strip; and a dividing sheer configured to cut the straightened clad strip to a fixed length or a coiler configured to coil the straightened clad strip.

2. A process comprising: sending a base material strip through a pinch roll to a shot blasting machine for a surface cleaning; welding the shot-blasted base material strips head-to-tail using a welding equipment so as to supply the base material strips continuously; sending the welded base material strip through a welding pinch roll to an induction heating apparatus for heating; sending the heated base material strip to a mold through a guiding roll, where the base material strip enters the mold along the middle interior of the mold from above and passes through the mold at a rate of 0.1˜30 m/min; infusing a molten clad melt in a tundish into the mold with argon blowing on a mold surface to prevent the molten clad melt from oxidation, wherein: a temperature of the molten clad melt is 30˜150° C. higher than a melting point of the base material strip, the molten clad melt, which has a high temperature, contacts a surface of the base material strip, which has a low temperature, leading to a slight melt on the surface of the base material strip, and the molten clad melt is solidified on the surface of the base material strip having the low temperature, so as to achieve a melting clad, the low temperature of the surface of the base material strip and a copper plate of the mold cause the molten clad melt to gradually solidify and form a clad slab; passing the clad slab formed in the mold through the mold to a secondary cooling section, where cooling water is sprayed on an upper and a lower surface of the clad slab within the secondary cooling section to further solidify the clad slab; leveling the clad slab after cooling by passing through a leveling roll and continuing into a rolling mill to be rolled into a clad strip, where a clad interface of the clad strip is compressed and deformed at a high temperature during the rolling process, a microstructure of a clad interface structure recovers and recrystallizes, and recombination of the interface promoted by a grain growth and an element diffusion under high temperature; cooling the clad strip after rolling by on-line cooling equipment; transporting the clad strip after above cooling to a straightening machine for straightening; and cutting the clad strip into a fixed length by a dividing shear or coiling the clad strip by a coiler.

3. The process of claim 2, wherein the clad slab is a single-sided clad slab.

4. The process of claim 2, further comprising infusing one or two kind of a molten clad melt in a second tundish into the mold, wherein the clad slab is a double-sided clad slab.

5. The process of claim 2, wherein the induction heating apparatus is filled with a nitrogen or an argon protection atmosphere.

6. The process of claim 2, wherein a heating temperature of the induction heating apparatus ranges from 850° C. to 1200° C., and a heating rate of the induction heating apparatus ranges from 1˜50° C./s.

7. The process of claim 2, wherein the base material strips is selected from carbon steel, stainless steel, special alloy steel, titanium, or copper.

8. The process of claim 2, wherein the heating by the induction heating apparatus comprises merging the base material strip and a molten clad layer.

9. The process of claim 2, wherein the heating by the induction heating apparatus comprises accelerating melting of a surface metal of the base material strip.

10. The process of claim 2, wherein the molten clad melt is selected from carbon steel, stainless steel, special alloy steel, titanium, and copper.

11. The process of claim 2, wherein an on-line cooling rate of the on-line cooling equipment ranges from 1° C./s to 60° C./s, and a finish cooling temperature ranges from 50° C. to 600° C.

12. The process of claim 2, wherein the base material strip has a thickness of 2˜20 mm.

13. The process of claim 12, further comprising decoiling the base material strip.

14. The process of claim 2, wherein the base material strip has a thickness of 21-100 mm.

15. The process of claim 14, wherein the base material strip is sent directly through the pinch roll to the shot blasting machine.

Description

FIGURE DESCRIPTION

(1) The FIGURE shows a schematic diagram of the device and method for manufacturing metal continuously according to the present invention, in which: 1—decoiler, 2—pinch roll, 3—shot blasting machine, 4—welding equipment, 5—welding pinch roll, 6—induction heating apparatus, 7—guiding roll, 8—mold, 9—tundish, 10—secondary cooling section, 11—leveling roll, 12—rolling mill, 13—on-line cooling equipment, 14—straightening machine, 15—dividing shear, 16—coiler, A—base material strip, B—clad slab, C—clad strip.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(2) In the following, a device and method for manufacturing metal clad strips continuously provided by the present invention will be further described with reference to the drawings and embodiments.

Example 1: Double-Sided Clad Strips

(3) 1) Decoiling Q345B having a thickness of 20 mm with decoiler and sending it to shot blasting machine through pinch roll for surface cleaning, then welding the tail of shot-blasted strip to the head of the next shot-blasted strip by welding equipment so as to supply Q345B continuously; 2) The welded Q345B is transported through welding pinch roll to induction heating apparatus to be heated, wherein the induction heating apparatus is filled with nitrogen for protection, the heating temperature is 850° C., the heating speed is 10° C./s; 3) The heated Q345B passes through the mold along the middle inside of the mold at a speed of 3 m/min, and infusing the molten clad melt of 316L stainless steel in the two tundishes (9) into the mold with argon blowing on the mold surface to prevent the molten clad melt from oxidation, wherein the pouring temperature is 1550° C. The molten clad melt of 316L contacts the surface of the Q345B which surface is slightly melt, so as to achieve the primary melting clad of the clad layer and the base layer, and finally form a double-sided clad slab with a base layer of Q345B and clad layers of 316L, which has a thickness of 5+20+5 mm. 4) The double-sided clad slab formed in the mold passes through the mold and enters into secondary cooling section, where cooling water is sprayed on the upper and lower surfaces of the clad slab to further solidify the incompletely solidified clad material, meanwhile rapid cooling prevents the grains generated by surface solidification from growing and coarsening; 5) The cooled clad slab is transported to rolling mill at 1120° C. to be rolled into a double-sided clad strip with a thickness of 6 mm(1+4+1 mm), and the final rolling temperature is 1000° C. The rolled clad strip is cooled on-line, wherein the start cooling temperature is 950° C., the final cooling temperature is 540° C., and the cooling rate is 35° C./s; 6) The cooled clad strip is transported to straightening machine for straightening, and the straightened clad strip is coiled on-line by a coiler.

Example 2: Single-Sided Clad Strips

(4) 1) Decoiling AH36 carbon steel having a thickness of 40 mm with decoiler and sending it to shot blasting machine through pinch roll for surface cleaning, then welding the tail of shot-blasted strip to the head of the next shot-blasted strip by welding equipment so as to supply AH36 continuously; 2) The welded carbon steel is transported through welding pinch roll to induction heating apparatus to be heated, wherein the induction heating apparatus is filled with nitrogen for protection, the heating temperature is 900° C., the heating speed is 15° C./s; 3) The heated carbon steel passes through the mold along the middle inside of the mold at a speed of 1.8 m/min, and infusing the molten clad melt of 304L stainless steel in one of the tundishes into the mold with argon blowing on the mold surface to prevent the molten clad melt from oxidation, wherein the pouring temperature is 1580° C. The molten clad melt of 304L contacts the surface of the carbon steel which surface is slightly melt, so as to achieve the primary melting clad of the clad layer and the base layer, and finally form a single-sided clad slab with a base layer of AH36 carbon steel and clad layer of 304L, which has a thickness of 40+8 mm. 4) The single-sided clad slab formed in the mold passes through the mold and enters into secondary cooling section, where cooling water is sprayed on the upper and lower surfaces of the clad slab to further solidify the incompletely solidified clad material, meanwhile rapid cooling prevents the grains generated by surface solidification from growing and coarsening; 5) The cooled clad slab is transported to rolling mill at 1150° C. to be rolled into a single-sided clad strip with a thickness of 6 mm(5+1 mm), and the final rolling temperature is 970° C. The rolled clad strip is cooled on-line, wherein the start cooling temperature is 910° C., the final cooling temperature is 420° C., and the cooling rate is 40° C./s; 6) The cooled clad strip is transported to straightening machine for straightening, and the straightened clad strip is coiled on-line by a coiler.

(5) The device and method for manufacturing metal clad strips continuously casting and rolling provided by the present invention, combines the continuous casting, rolling and heat treatment methods used for single material manufacture with the continuous and large-scale manufacture method of clad strip, greatly improves the productivity of clad strips and plates. The present invention can be used for manufacturing single-sided or double-sided clad plates and strips with different thickness specifications, wherein the base layer material or the clad material can be selected in a wide range, including carbon steel, stainless steel, special alloy steel, titanium, copper and the like. In the present application, continuous casting and rolling clad strip is implemented, which decrease the energy consumption and costs.