| 摘要 |
PURPOSE:To make the manufacture of the steel hoop of magnetic shielding material capable of being worked in a bending manner by a process smaller than traditional one, by applying primary cold rolling and the decarburizing annealing and secondary cold rolling by specific conditions to the carbon hot rolled steel hoop of material in manufacturing the material steel hoop of magnetic shield for color picture tube. CONSTITUTION:The steel hoop capable of manufacturing the magnetic shield of high permeability, high mechanical strength, grain size of ASTM No.7-9 processed by blocking treatment and relative permeability (0.35 Oe) of 700min., capable of easily being worked by bending in a funnel state as the material of magnetic shield used in color picture tube, is manufactured. The hot rolled steel hoop of under 0.12% C, 0.10-0.50% Mn, under 0.02% Si, under 0.03% P, under 0.03% S, under 0.01% soluble Al and 0.0001-0.01% N is worked with primary cold rolling, open coil decarburizing annealing of under 0.01% C and secondary cold rolling of 40-90% in draft. Thereafter, it is worked in a bending manner into magnetic shield, further processed with blacking treatment for 10-30min at 550-650 deg.C and mounted into color picture tube. Then, the magnetic shield can be obtained by a process simpler than traditional one at a low cost. |
