The battery shell steel strip is a deep drawing strip, and the 0.25 mm steel strip is used to punch the No.5 battery shell. In processing 0.25mm steel strip, the shell appears orange peel surface defects and lug phenomenon. This surface defects seriously affects the appearance of the battery shell and the quality of subsequent processing; and the lug will prevent the normal operation of the manipulator in the continuous shelling process, affecting the continuous automated production and that will produce inferior-quality products and waste products.
The test results show that the 0.25mm steel strip rolled with 0.35mm steel strip appear orange peel surface defects in the shells with the grain size of 5, and it is accompanied by mixed crystal phenomenon, so the organization is unqualified. When the 0.25mm steel strip rolled with 0.65mm steel strip is in the shells, the lug phenomenon is serious.
The induction heat treatment process and performance test of the two kinds of steel strip are carried out by several schemes. The induction annealing heat treatment process with induction annealing machine to prevent the deep drawing defects is as follows:
(1) Selecting the 0.25mm steel strip that is rolled with 0.35mm steel strip of the grain size of 7 or more. Using induction annealing machine for shells on the battery shell steel strip's low temperature annealing process at 600 ℃ with 16 hours. After annealing, grain size is 7. Steel strip after the shell does not appear orange peel-like surfac defects to meet the technical requirements.
(2) Using isothermal treatment at 560 ℃ with 12 hours and insulation annealing process in processing strip at 640 ℃ with 12h. It can eliminate the adverse texture, so that the beneficial texture is strengthened to effectively reduce and eliminate the anisotropy of materials, greatly reducing and avoid the lug defects.