| 摘要 |
PROBLEM TO BE SOLVED: To provide an aluminum alloy extruded stock excellent in spot weldability, and to prevent degradation of a welding electrode and reduction in strength of a weld zone by grinding the surface of the extruded stock at the prescribed temperature with a rotary brush after extrusion to remove the oxide film on the surface. SOLUTION: Nylon brush rolls 1 of 300mm in roll diameter are installed on an run-out table at the position of 5m from an outlet of a die 2 above and below an extruded stock D. The rolls 1 are turned in a reverse direction to the feeding direction of the extruded stock D at 1200rpm in the number of revolution of the motor. A cooling fan 3 is installed between the brush rolls 1 and the die 2 and the temperature of the extruded stock D at the position of the brush rolls 1 is <=250 deg.C. After the oxide film on the surface of the extruded stock is removed, the oxide film is generated again, and the thickness of the oxide film is preferably <=100Å, and its surface roughness is <=10μm in Rz.
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