| 摘要 |
PURPOSE:To remove captured gas or impurities out of the solder for better workability and better ductility, by remelting Sn-Pb soldering alloy while agitating it in a specified degree of vacuum and by cold-forming after freezing with specified velocity of rapid cooling. CONSTITUTION:Sn or Pb metal melted in the reduced pressure or plural metals consisting essentially of either of Sn metal and Pb metal are melted in the atmosphere and are made to Sn-Pb alloy. Or plural metals consisting essentially of Sn metal and Pb metal are melted in the atmosphere and made to Sn-Pb alloy in the reduced pressure. Or plural metals consisting essentialy of Sn metal or Pb metal melted in the atmopshere are melted in the atmosphere and made to Sn-Pb alloy. Next, either of the said alloy is remelted while agitating in reduced pressure of 5X10<-1> Torr or bellow and by freezing with the cooling velocity of 10 deg.C/min or more and is cold-formed to a solder of a desired shape. At the same time, the captured gas in the metals or alloys and the entrained gas during casting as well as impurities are removed. And the grain size is also made finer and less segregated by the rapid of freezing and cold forming. |
