| 摘要 |
PURPOSE:To obtain an Al extruding material having a good mechanical quality blowing at a high speed a mixture of water and air under a specified jet conditions, to an Al extruding material immediately after extrusion in an end platen of an extruding machine, and cooling it at a high cooling speed. CONSTITUTION:In an end platen 3 of an extruding machine provided with a container 1, a die slide 2, etc., a mixture of water and air is blown to an Al extruding material W of an extruding device from a water - air mixing jet nozzle 6 at a high speed from the circumference under a jet condition for satisfying the following expression; Y>=9-4X+0.5X<2> (provided that Y; quantity of water, l/min and X; air pressure of the tip of a nozzle, kg/cm<2>). As a result, membrane boiling of the surface of the extruding material W is broken, the extruding material W is cooled at a cooling speed of about 1,000 deg.C/min or above, generation of surface recrystallization on the extruding material W is prevented, and a drop of corrosion resistance and fatigue strength, a heat-affected crack at the time of welding, a drop of a forming property, etc. can be prevented. |
