CN-122007323-A - Cobalt starting sheet lug heating riveting process

CN122007323ACN 122007323 ACN122007323 ACN 122007323ACN-122007323-A

Abstract

The invention discloses a cobalt starting sheet lug heating riveting process, belongs to the field of nonferrous metal metallurgy, and solves the problems of easiness in cracking, high contact resistance and large heat affected zone of a welding process in cold riveting. The process comprises the steps of processing a riveting hole on a cobalt starting sheet, locally heating a region to be riveted of a cobalt lug to enable the temperature of the cobalt lug in the region to be increased to the phase change temperature of the region, conveying the cobalt lug in a heated state to the riveting position of the cobalt starting sheet, applying pressure to enable a cobalt material softened by heating to generate plastic flow and fill the cobalt material into the riveting hole of the cobalt starting sheet to form a mechanically interlocked riveting point, maintaining the pressure until the riveting point is initially shaped and then releasing pressure, wherein the cobalt lug is contracted in the cooling process, and therefore clamping force is generated at the joint. According to the invention, the cobalt lug riveting area is softened by local heating, the thermoplastic is utilized for riveting, the micro-crack and cracking phenomenon generated by cold riveting are thoroughly avoided, and the tensile stripping strength and reliability of the connecting point are obviously improved.

Inventors

YAO HUI
Gao Haiyin
CHEN RUISHAN
FENG YUJIE
HU YONGJI
YUE ZHIZHOU
ZHOU LINHUA
SUN DONGMING
XIANG YUANCHUN

Assignees

金川集团镍钴股份有限公司
兰州金川新材料科技股份有限公司
昆明理工大机电装备集成科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260319

Claims (8)

1. The heating and riveting process for the cobalt starting sheet lug is characterized by comprising the following steps of: A. feeding, namely providing a cobalt starting sheet and a cobalt lug, and processing a riveting hole at a position on the cobalt starting sheet, where the cobalt lug is required to be mounted; B. Local heating, namely using a heating device to locally heat a region to be riveted of the cobalt lug, so that the temperature of the cobalt lug in the region is increased to the phase transition temperature of the cobalt lug; C. Pressurizing and riveting, namely conveying the heated cobalt lug to a riveting position of the cobalt starting sheet, applying pressure through pressure equipment, and enabling the heated and softened cobalt material to generate plastic flow and fill the plastic flow into a riveting hole of the cobalt starting sheet to form a mechanically interlocked riveting point; D. And (3) pressure maintaining and cooling, namely, pressure is maintained until the riveting point is preliminarily shaped, then pressure is released, the workpiece is cooled to the room temperature, and the cobalt lug can shrink in the cooling process, so that clamping force is generated at the joint, and after the cobalt lug is completely cooled, the riveting operation is completed.
2. The cobalt starting sheet tab heating and riveting process as claimed in claim 1, wherein in the step B, the area to be riveted of the cobalt tab is heated to 450-750 ℃.
3. The process for heating and riveting the cobalt starting sheet lug according to claim 2 is characterized in that in the step B, a non-contact heating mode is adopted to locally heat the region to be riveted of the cobalt starting sheet lug.
4. The process for heating and riveting a cobalt starting sheet lug as claimed in claim 3, wherein the non-contact heating mode comprises heat treatment furnace heating, induction heating, laser heating, infrared heating or electron beam heating.
5. The cobalt starting sheet lug heating riveting process as claimed in claim 4, wherein the laser heating is performed by using an optical fiber laser or a disc laser, the laser spot diameter is 1-5 mm, and the power is 500-3000W.
6. The process for heating and riveting cobalt starting sheet lugs according to claim 4, wherein the heat treatment furnace comprises a resistance furnace, a fuel furnace, an induction furnace or a vacuum furnace.
7. The process for heating and riveting a cobalt starting sheet tab according to claim 1, wherein in the step C, the pressure is applied in a range of 10-50 kN, and the dwell time is 0.5-3 seconds.
8. The process for heating and riveting a cobalt starting sheet tab according to claim 7, wherein in step C, the pressure device comprises a hydraulic press, a pneumatic press or a servo-electric press.

Description

Cobalt starting sheet lug heating riveting process Technical Field The invention belongs to the field of nonferrous metal metallurgy, and particularly relates to a cobalt starting sheet lug heating riveting process. Background In the cobalt electrorefining process, it is necessary to firmly attach a copper conductive tab to a cobalt starting sheet to form a cathode. Traditional means of attachment include welding and cold staking. However, welding (e.g., arc welding, brazing) has problems of large heat affected zone, easy deformation of thin starting sheet, possibility of impurity introduction affecting cobalt purity, high energy consumption and low efficiency. Although the efficiency of cold riveting is higher, the cobalt starting sheet has high hardness and poor ductility at room temperature, and the direct riveting is extremely easy to generate micro cracks at the periphery of the riveting point, and even leads to the cracking of the starting sheet. Meanwhile, the mechanical connection formed by cold riveting is insufficient in contact area, the contact resistance is large, when high-intensity electrolytic current passes through, the connection part is easy to generate heat, so that energy waste is caused, even the connection point is caused to fail, and the stable operation of the electrolytic tank is influenced. Disclosure of Invention The invention aims to provide a cobalt starting sheet lug heating riveting process, which aims to solve the problems of easiness in cracking, high contact resistance and large heat affected zone of a welding process in cold riveting. The technical scheme of the invention is that the cobalt starting sheet lug heating riveting process comprises the following steps: A. feeding, namely providing a cobalt starting sheet and a cobalt lug, and processing a riveting hole at a position on the cobalt starting sheet, where the cobalt lug is required to be mounted; B. Local heating, namely using a heating device to locally heat a region to be riveted of the cobalt lug, so that the temperature of the cobalt lug in the region is increased to the phase transition temperature of the cobalt lug; C. Pressurizing and riveting, namely conveying the heated cobalt lug to a riveting position of the cobalt starting sheet, applying pressure through pressure equipment, and enabling the heated and softened cobalt material to generate plastic flow and fill the plastic flow into a riveting hole of the cobalt starting sheet to form a mechanically interlocked riveting point; D. And (3) pressure maintaining and cooling, namely, pressure is maintained until the riveting point is preliminarily shaped, then pressure is released, the workpiece is cooled to the room temperature, and the cobalt lug can shrink in the cooling process, so that a strong clamping force is generated at the joint, and after the cobalt lug is completely cooled, the riveting operation is completed. As a further improvement of the invention, in step B, the region of the cobalt ear to be riveted is heated to 450-750 ℃. The temperature interval is far higher than the HCP-to-FCC phase transition temperature (417 ℃) of cobalt, ensures that cobalt is in a high-plasticity state of a face-centered cubic structure, is far lower than the melting point (1495 ℃) of cobalt, and avoids the risk of overgrowth or melting of crystal grains. As a further improvement of the invention, in step B, the area to be riveted of the cobalt ear is locally heated by means of non-contact heating. As a further improvement of the invention, the non-contact heating mode comprises heat treatment furnace heating, induction heating, laser heating, infrared heating or electron beam heating. As a further improvement of the invention, a fiber laser or a disc laser is adopted for laser heating, the laser spot diameter is 1-5 mm, and the power is 500-3000W. As a further improvement of the present invention, the heat treatment furnace includes a resistance furnace, a fuel furnace, an induction furnace, or a vacuum furnace. As a further improvement of the invention, in the step C, the pressure applied is in the range of 10-50 kN, and the dwell time is 0.5-3 seconds. As a further development of the invention, in step C, the pressure device comprises a hydraulic press, a pneumatic press or a servo-electric press. The beneficial effects of the invention are as follows: 1. The joint strength is high, no cracks exist, namely the cobalt lug riveting area is softened by local heating, the thermoplastic is utilized for riveting, the micro cracks and cracking phenomena generated by cold riveting are thoroughly avoided, and the tensile stripping strength and the reliability of the joint point are obviously improved. 2. The high-temperature and high-pressure combined action breaks through an oxide film on the surface of the material, so that the cobalt lug and the starting sheet are in large-area close contact, the physical connection with extremely low contact resistance is formed, and