Preparation method of precious metal strip

Abstract

The invention discloses a preparation method of a precious metal strip, which comprises the following steps: heating a silver ingot to 1100-1200 DEG C for melting, and pulling a plate at 70-150 DEG C to obtain a silver plate; the silver plate is subjected to preliminary rolling, the pass machining deformation is controlled to be 5%-25% till the thickness reaches 0.25-0.30 mm, and a roughly-rolled silver plate is obtained; the rough rolling silver plate is precisely rolled, the pass machining deformation is controlled to be 1%-10% till the target thickness is reached, and a fine rolling silver strip is obtained; the fine-rolled silver strip is subjected to separation forming, and a first-state product is obtained; and annealing the first-state product to obtain a second-state product. According to the method, through the process modes of vacuum continuous casting, continuous cold rolling and multi-channel striping, multiple strips can be produced at a time, and compared with a traditional wire process, the productivity is remarkably improved; the thickness tolerance of the strip can be well controlled through rough rolling and precise rolling of the silver plate.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, and in particular to a method for preparing a precious metal strip. Background Art

[0002] A fuse is a device that provides overcurrent protection for a circuit. It consists of three parts: a base, a contact, and a fuse. The fuse is the most important part, which includes a conductive end cap, a core column, a melt, quartz sand, and a porcelain tube. The melt material is the core component and is directly related to the performance of the fuse. The melt material is divided into two categories: low melting point and high melting point. Low melting point materials such as tin and lead alloys are easy to melt and have a high resistivity. The cross-sectional size of the melt is large, and more metal vapor is generated when it melts. It is only suitable for fuses with low breaking capacity; high melting point materials such as copper and silver are not easy to melt, and their resistivity is low. They can be made into smaller cross-sectional sizes, and less metal vapor is generated when they melt. They are suitable for fuses with high breaking capacity.

[0003] For fuses with low rated current, the melt is made into wires; for fuses with high rated current, it is made into strips. Pure silver strip is a high melting point melt material that is widely used at present. Silver melt has a good ability to break strong short-circuit currents. In addition, silver has stable chemical properties and excellent oxidation and corrosion resistance. During use, the resistance value is not easy to change and the melting point is constant, which is conducive to ensuring the stability and safety of the circuit. It is a key material for high-current and high-reliability fuses.

[0004] At present, pure silver melt mostly adopts strip structure, and the process is: the pure silver material is drawn multiple times, and finally the wire is cold-rolled to the target thickness. However, since only one wire can be drawn at a time during the wire drawing process, the finished product has a large width and thickness, which makes the wire flattening process difficult to control, and the wire flattening process itself causes the finished strip to have wavy edges, resulting in low silver strip production capacity, difficult process implementation, and unstable product quality. Summary of the invention

[0005] The present invention provides a method for preparing a precious metal strip, aiming to solve the above-mentioned problems existing in the background technology.

[0006] The technical solution provided by the present invention is as follows:

[0007] A method for preparing a precious metal strip comprises the following steps:

[0008] The silver ingot is heated to 1100-1200°C to melt, and the silver plate is drawn at 70-150°C to obtain a silver plate;

[0009] The silver plate is preliminarily rolled, and the deformation of each pass is controlled to be 5%-25%, until the thickness reaches 0.25-0.30 mm, so as to obtain a rough-rolled silver plate;

[0010] The rough-rolled silver plate is precision-rolled, and the deformation of each pass is controlled to be 1%-10% until the target thickness is reached, and the target thickness does not exceed 0.2 mm, to obtain a fine-rolled silver strip;

[0011] The fine rolled silver strip is formed in lanes to obtain a first state product;

[0012] The first-state product is annealed to obtain a second-state product.

[0013] Furthermore, during the initial rolling process of the silver plate, multiple annealing processes are performed, with the annealing temperature being 280-580° C. and the time being 1.5-4 hours.

[0014] Furthermore, during the precision rolling of the rough-rolled silver plate, multiple annealings are performed, with the annealing temperature being 280-350° C. and the time being 1.5-4 hours.

[0015] Furthermore, the fine rolled silver strip is formed in lanes as follows: the fine rolled silver strip is installed on a multi-lane slitting machine, the strip feeding angle and speed are adjusted, a plurality of silver strip winding reels are installed, and the strip is formed in lanes on the multi-lane slitting machine according to the width.

[0016] Furthermore, the number of the silver ribbon winding reels is 18, and the blade width of the multi-lane slitting machine is 2.45 mm.

[0017] Furthermore, the silver ingot is heated to 1100-1200°C to melt, and the plate is drawn at 70-150°C. Specifically, the silver ingot is placed in a high vacuum continuous casting machine, heated to 1100-1200°C to melt the silver ingot, a stainless steel lead rod is inserted into the lower mill of the graphite crucible of the high vacuum continuous casting machine, and the plate is drawn at 70-150°C.

[0018] Further, the first state product is annealed, specifically: the first state product is placed in a dynamic online continuous annealing system for annealing, the annealing furnace temperature is 350°C to 750°C, and the belt speed is 1.0-3.0 m·min -1 .

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The method for preparing precious metal strips provided by the present invention can produce 18 strips at a time through vacuum continuous casting, continuous cold rolling, and multi-pass stripping processes. Compared with the process of wire materials, the production capacity is significantly improved; the thickness tolerance of the silver plate can be well controlled through rough rolling and precision rolling; since the width tolerance of the multi-pass stripping blade meets the product requirements, the width tolerance of the strip also meets the requirements. Through high vacuum continuous casting of silver plates, the silver plates have low oxygen content, few internal pores, uniform organization, improved product quality, and the prepared products do not have "wave" patterns. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart of the method for preparing the precious metal strip provided by the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are part of the embodiments of the present application, not all of the embodiments.

[0023] See also Figure 1 The present invention provides a method for preparing a precious metal strip, comprising the following steps:

[0024] Step S1, heating the silver ingot to 1100-1200°C to melt it, and drawing it into a plate at 70-150°C to obtain a silver plate.

[0025] Step S2, preliminarily rolling the silver plate, controlling the deformation of each pass to be 5%-25%, until the thickness reaches 0.25-0.30 mm, to obtain a roughly rolled silver plate.

[0026] Step S3, precision rolling the rough-rolled silver plate, controlling the deformation of each pass to be 1%-10%, until the target thickness is reached, and the target thickness does not exceed 0.2mm, to obtain a fine-rolled silver strip.

[0027] Step S4, forming the fine rolled silver strip into lanes to obtain a first state product.

[0028] Step S5: annealing the first-state product to obtain a second-state product, which is the final product.

[0029] Optionally, during the initial rolling process of the silver plate, multiple annealings are performed, with the annealing temperature being 280-580° C. and the time being 1.5-4 h.

[0030] Optionally, during the precision rolling of the rough-rolled silver plate, multiple annealings are interspersed, with the annealing temperature being 280-350° C. and the time being 1.5-4 h.

[0031] Optionally, the fine rolled silver strip is formed in lanes by installing the fine rolled silver strip on a multi-lane slitting machine, adjusting the strip feeding angle and speed, installing a plurality of silver strip take-up reels, and forming the strip in lanes on the multi-lane slitting machine according to the width.

[0032] Optionally, the number of the silver ribbon take-up reels is 18, and the blade width of the multi-lane slitting machine is 2.45 mm.

[0033] Optionally, the silver ingot is heated to 1100-1200° C. to melt, and the plate is drawn at 70-150° C. Specifically, the silver ingot is placed in a high vacuum continuous casting machine, heated to 1100-1200° C. to melt the silver ingot, a stainless steel lead rod is inserted into the lower mill of the graphite crucible of the high vacuum continuous casting machine, and the plate is drawn at 70-150° C. By high vacuum continuous casting of the silver plate, the silver plate has low oxygen content, few internal pores, and uniform structure.

[0034] Optionally, the first state product is annealed, specifically: the first state product is placed in a dynamic online continuous annealing system for annealing, the annealing furnace temperature is 350°C-750°C, and the belt speed is 1.0-3.0 m·min -1 .

[0035] The preparation method is further described below in conjunction with specific examples.

[0036] Example 1

[0037] This embodiment provides a method for preparing a precious metal strip, comprising the following steps:

[0038] Step 101, place the standard silver ingot into a high vacuum continuous casting machine, heat it to 1160°C to melt the silver ingot, insert a stainless steel guide rod into the lower mill of the graphite crucible of the casting machine, and crystallize it at 80°C to pull out a silver plate, the width and thickness of the pulled silver plate is 50mm*5mm.

[0039] Step 102, rolling the silver plate on a rolling mill, with a processing deformation of 15% per pass, annealing is performed at the 5th / 10th / 15th / 18th pass respectively, with an annealing temperature of 320° C. for 2 hours, and then cooling to room temperature in the furnace.

[0040] Step 103, after 18 times of rolling in step 102, the silver plate has a thickness of 0.27 mm, and is transferred to a precision press for precision rolling. The silver plate is slowly rolled by the precision press, the rolling times are 6 times, the deformation of each pass is 5%, and annealing is performed at the 3rd / 6th time, the annealing temperature is 280°C, the time is 1.5 hours, until the rolling thickness reaches 0.20 mm, and the silver plate roll with a thickness of 0.20 mm is obtained after cooling in the furnace to room temperature.

[0041] Step 104, install the silver plate roller on the multi-lane slitting machine, adjust the belt feeding angle and speed, install 18 sets of blades with a width of 2.45 mm and 18 silver belt winding reels, and perform lane forming on the multi-lane slitting machine.

[0042] Step 105: After the lane forming, the product is placed in a dynamic online continuous annealing system for annealing. The annealing furnace temperature is 500°C and the belt speed is 2.0 m / min. -1 , the product is formed to obtain the required silver ribbon.

[0043] The silver ribbon was tested and found to have a width of 2.45±0.005 mm, a thickness of 0.20±0.008 mm, and a resistivity of 36.8±0.4 mΩ·m.

[0044] Example 2

[0045] This embodiment provides a method for preparing a precious metal strip, comprising the following steps:

[0046] Step 201, place the standard silver ingot into a high vacuum continuous casting machine, heat it to 1160°C to melt the silver ingot, insert a stainless steel guide rod into the lower mill of the graphite crucible of the casting machine, and crystallize it at 100°C to pull out a silver plate, the width and thickness of the pulled silver plate is 50mm*5mm.

[0047] Step 202, rolling the silver plate on a rolling mill, with a processing deformation of 15% per pass, annealing is performed at the 5th / 10th / 15th / 18th pass respectively, with an annealing temperature of 320° C. for 2 hours, and then cooling to room temperature in the furnace.

[0048] Step 203, after 18 times of rolling, the silver plate has a thickness of 0.27 mm and is transferred to a precision press for precision rolling. The silver plate is slowly rolled with a precision press, and the deformation of each pass is 5%. Annealing is performed at the 3rd and 6th times, respectively, at a temperature of 280°C for 1.5 hours, until the rolled thickness reaches 0.20 mm, and the silver plate roll is cooled to room temperature in the furnace to obtain a silver plate roll with a thickness of 0.20 mm.

[0049] Step 204, install the silver plate roller on the multi-lane slitting machine, adjust the belt feeding angle and speed, install 18 sets of blades with a width of 2.45 mm and 18 silver belt winding reels, and perform lane forming on the multi-lane slitting machine.

[0050] Step 205: After the lane forming, the product is placed in a dynamic online continuous annealing system. The annealing furnace temperature is 500°C and the belt speed is 2.0 m / min. -1 , the product is formed to obtain the required silver ribbon.

[0051] The silver ribbon was tested and found to have a width of 2.45±0.005 mm, a thickness of 0.20±0.008 mm, and a resistivity of 36.8±0.4 mΩ·m.

[0052] Example 3

[0053] This embodiment provides a method for preparing a precious metal strip, comprising the following steps:

[0054] Step 301, place the standard silver ingot into a high vacuum continuous casting machine, heat it to 1160°C to melt the silver ingot, insert a stainless steel guide rod into the lower mill of the graphite crucible of the casting machine, and crystallize it at 80°C to pull out a silver plate, the width and thickness of the pulled silver plate is 50mm*5mm.

[0055] Step 302, rolling the silver plate on a rolling mill, with a processing deformation of 10% per pass, annealing is performed at the 5th / 10th / 15th / 20th / 25th passes respectively, with an annealing temperature of 320°C for 2 hours, and then cooled to room temperature in the furnace.

[0056] Step 303, after 27 times of rolling, the silver plate has a thickness of 0.29 mm and is transferred to a precision press for precision rolling. The silver plate is slowly rolled with a precision press, and the deformation of each pass is 5%. Annealing is performed at the 3rd and 6th times, respectively, at a temperature of 280°C for 1.5 hours, until the rolled thickness reaches 0.20 mm, and the furnace is cooled to room temperature. A silver plate roll with a thickness of 0.20 mm is obtained.

[0057] Step 304, install the silver plate roller on the multi-lane slitting machine, adjust the belt feeding angle and speed, install 18 sets of blades with a width of 2.45 mm and 18 silver belt winding reels, and perform lane forming on the multi-lane slitting machine.

[0058] Step 305: After the lane forming, the product is placed in a dynamic online continuous annealing system. The annealing furnace temperature is 500°C and the belt speed is 2.0 m / min. -1 , the product is formed to obtain the required silver ribbon.

[0059] The silver ribbon was tested and found to have a width of 2.45±0.005 mm, a thickness of 0.20±0.005 mm, and a resistivity of 36.8±0.3 mΩ·m.

[0060] Example 4

[0061] This embodiment provides a method for preparing a precious metal strip, comprising the following steps:

[0062] Step 401, place the standard silver ingot into a high vacuum continuous casting machine, heat it to 1160°C to melt the silver ingot, insert a stainless steel guide rod into the lower mill of the graphite crucible of the casting machine, and crystallize it at 80°C to pull out a silver plate, the width and thickness of the pulled silver plate is 50mm*5mm.

[0063] Step 402, rolling the silver plate on a rolling mill, with a processing deformation of 20% per pass, annealing is performed at the 5th / 10th / 13th pass respectively, with an annealing temperature of 320°C for 2 hours, and then cooled to room temperature in the furnace.

[0064] Step 403, after 13 times of rolling, the silver plate has a thickness of 0.27 mm and is transferred to a precision press for precision rolling. The silver plate is slowly rolled with a precision press, and the deformation of each pass is 5%. Annealing is performed at the 3rd and 6th times, respectively, at a temperature of 280°C for 1.5 hours, until the rolled thickness reaches 0.20 mm, and the silver plate roll is cooled to room temperature in the furnace to obtain a silver plate roll with a thickness of 0.20 mm.

[0065] Step 404, install the silver plate roller on the multi-lane slitting machine, adjust the belt feeding angle and speed, install 18 sets of blades with a width of 2.45 mm and 18 silver belt take-up reels, and perform lane forming on the multi-lane slitting machine.

[0066] Step 405: After the lane forming, the product is placed in a dynamic online continuous annealing system. The annealing furnace temperature is 500°C and the belt speed is 2.0 m / min. -1 The product is formed into the desired silver ribbon. After testing the silver ribbon, the width is 2.45±0.005mm, the thickness is 0.20±0.011mm, and the meter resistance is 35.9±1.2mΩ·m.

[0067] Example 5

[0068] This embodiment provides a method for preparing a precious metal strip, comprising the following steps:

[0069] Step 501, place the standard silver ingot into a high vacuum continuous casting machine, heat it to 1160°C to melt the silver ingot, insert a stainless steel guide rod into the lower mill of the graphite crucible of the casting machine, and crystallize it at 80°C to pull out a silver plate, the width and thickness of the pulled silver plate is 50mm*5mm.

[0070] Step 502, rolling the silver plate on a rolling mill, with a processing deformation of 15% per pass, annealing is performed at the 5th / 10th / 15th / 18th pass respectively, with an annealing temperature of 320°C for 2 hours, and then cooled to room temperature in the furnace.

[0071] Step 503, after 18 times of rolling, the silver plate has a thickness of 0.27 mm and is transferred to a precision press for precision rolling. The silver plate is slowly rolled with a precision press, and the deformation of each pass is 5%. Annealing is performed at the 3rd and 6th times, respectively, at a temperature of 280°C for 1.5 hours, until the rolled thickness reaches 0.20 mm, and the silver plate roll is cooled to room temperature in the furnace to obtain a silver plate roll with a thickness of 0.20 mm.

[0072] Step 504, install the silver plate roller on the multi-lane slitting machine, adjust the belt feeding angle and speed, install 18 sets of blades with a width of 2.45 mm and 18 silver belt take-up reels, and perform lane forming on the multi-lane slitting machine.

[0073] Step 505: After the lane forming, the product is placed in a dynamic online continuous annealing system. The annealing furnace temperature is 600°C and the belt speed is 2.0 m / min. -1 , the product is formed to obtain the required silver ribbon.

[0074] The silver ribbon was tested and found to have a width of 2.45±0.005 mm, a thickness of 0.20±0.008 mm, and a resistivity of 35.3±0.3 mΩ·m.

[0075] Example 6

[0076] This embodiment provides a method for preparing a precious metal strip, comprising the following steps:

[0077] Step 601, place the standard silver ingot into a high vacuum continuous casting machine, heat it to 1160°C to melt the silver ingot, insert a stainless steel guide rod into the lower mill of the graphite crucible of the casting machine, and crystallize it at 80°C to pull out a silver plate, the width and thickness of the pulled silver plate is 50mm*5mm.

[0078] Step 602, rolling the silver plate on a rolling mill, with a processing deformation of 15% per pass, annealing is performed at the 5th / 10th / 15th / 18th pass respectively, with an annealing temperature of 320°C for 2 hours, and then cooled to room temperature in the furnace.

[0079] Step 603, after 18 times of rolling, the silver plate has a thickness of 0.27 mm and is transferred to a precision press for precision rolling. The silver plate is slowly rolled with a precision press, and the deformation of each pass is 5%. Annealing is performed at the 3rd and 6th times, respectively, at a temperature of 280°C for 1.5 hours, until the rolled thickness reaches 0.20 mm, and then cooled to room temperature in the furnace to obtain a silver plate roll with a thickness of 0.20 mm.

[0080] Step 604, install the silver plate roller on the multi-lane slitting machine, adjust the belt feeding angle and speed, install 18 sets of blades with a width of 2.45 mm and 18 silver belt take-up reels, and perform lane forming on the multi-lane slitting machine.

[0081] Step 605: After lane forming, the product is placed in a dynamic online continuous annealing system. The annealing furnace temperature is 700°C, the belt speed is 2.0 m·min-1, and the product is formed to obtain the required silver ribbon.

[0082] The silver ribbon was tested and found to have a width of 2.45±0.005 mm, a thickness of 0.20±0.008 mm, and a resistivity of 34.9±0.3 mΩ·m.

[0083] Example 7

[0084] This embodiment provides a method for preparing a precious metal strip, comprising the following steps:

[0085] Step 701, place the standard silver ingot into a high vacuum continuous casting machine, heat it to 1160°C to melt the silver ingot, insert a stainless steel guide rod into the lower mill of the graphite crucible of the casting machine, and crystallize it at 80°C to pull out a silver plate, the width and thickness of the pulled silver plate is 50mm*5mm.

[0086] Step 702, rolling the silver plate on a rolling mill, with a processing deformation of 15% per pass, annealing is performed at the 5th / 10th / 15th / 18th pass respectively, with an annealing temperature of 320°C for 2 hours, and then cooled to room temperature in the furnace.

[0087] Step 703, after 18 times of rolling, the silver plate has a thickness of 0.27 mm and is transferred to a precision press for precision rolling. The silver plate is slowly rolled with a precision press, and the deformation of each pass is 5%. Annealing is performed at the 3rd and 6th times, respectively, at a temperature of 280°C for 1.5 hours, until the rolled thickness reaches 0.20 mm, and the silver plate roll is cooled to room temperature in the furnace to obtain a silver plate roll with a thickness of 0.20 mm.

[0088] Step 704, install the silver plate roller on the multi-lane slitting machine, adjust the belt feeding angle and speed, install 18 sets of blades with a width of 2.45 mm and 18 silver belt winding reels, and perform lane forming on the multi-lane slitting machine.

[0089] Step 705: After the lane forming, the product is placed in a dynamic online continuous annealing system. The annealing furnace temperature is 700°C and the belt speed is 1.5 m / min. -1 , the product is formed to obtain the required silver ribbon.

[0090] The silver ribbon was tested and found to have a width of 2.45±0.005 mm, a thickness of 0.20±0.008 mm, and a resistivity of 34.8±0.2 mΩ·m.

[0091] The method for preparing precious metal strips provided by the present invention can produce 18 strips at a time through vacuum continuous casting, continuous cold rolling, and multi-pass stripping processes. Compared with the process of wire materials, the production capacity is significantly improved; the thickness tolerance of the silver plate can be well controlled through rough rolling and precision rolling; since the width tolerance of the multi-pass stripping blade meets the product requirements, the width tolerance of the strip also meets the requirements. Through high vacuum continuous casting of silver plates, the silver plates have low oxygen content, few internal pores, uniform organization, improved product quality, and the prepared products do not have "wave" patterns.

[0092] The above is only the best specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application shall be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for preparing a precious metal strip, characterized in that: The following steps are involved: The silver ingot is heated to 1100-1200°C to melt, and the silver plate is drawn at 70-150°C to obtain a silver plate; The silver plate is preliminarily rolled, and the deformation of each pass is controlled to be 5%-25%, until the thickness reaches 0.25-0.30 mm, so as to obtain a rough-rolled silver plate; The rough-rolled silver plate is precision-rolled, and the deformation amount of each pass is controlled to be 1%-10% until the target thickness is reached, and the target thickness does not exceed 0.2 mm, to obtain a fine-rolled silver strip; The fine rolled silver strip is formed in lanes to obtain a first state product; The first-state product is annealed to obtain a second-state product.

2. The method for preparing a precious metal strip according to claim 1, characterized in that: During the initial rolling process of the silver plate, multiple annealing is performed, with the annealing temperature being 280-580° C. and the time being 1.5-4 hours.

3. The method for preparing a precious metal strip according to claim 1, characterized in that: During the precision rolling of the rough-rolled silver plate, multiple annealings are interspersed, with the annealing temperature being 280-350° C. and the time being 1.5-4 hours.

4. The method for preparing a precious metal strip according to any one of claims 1 to 3, characterized in that: The specific steps of performing lane forming on the fine rolled silver strip are as follows: installing the fine rolled silver strip on a multi-lane slitting machine, adjusting the strip feeding angle and speed, installing a plurality of silver strip winding reels, and performing lane forming on the multi-lane slitting machine according to the width.

5. The method for preparing a precious metal strip according to claim 4, characterized in that: The number of the silver ribbon winding reels is 18, and the blade width of the multi-lane slitting machine is 2.45 mm.

6. The method for preparing a precious metal strip according to claim 4, characterized in that: The silver ingot is heated to 1100-1200°C to melt, and the plate is drawn at 70-150°C. Specifically, the silver ingot is placed in a high vacuum continuous casting machine, heated to 1100-1200°C to melt the silver ingot, a stainless steel lead rod is inserted into the lower mill of the graphite crucible of the high vacuum continuous casting machine, and the plate is drawn at 70-150°C.

7. The method for preparing a precious metal strip according to claim 5 or 6, characterized in that: The first state product is annealed, specifically: the first state product is placed in a dynamic online continuous annealing system for annealing, the annealing furnace temperature is 350° C. to 750° C., and the belt speed is 1.0-3.0 m·min -1 .

Images