| 摘要 |
The invention relates to a silver-based cadmium-free brazing alloy also containing other alloying elements such as Cu, Zn, Ti, Si and Mn in various ratios used for joining components made of Cu and Cu-based alloys used in electrical engineering and electronic industries and in other applications and to a process for preparing the same. The claimed alloy comprises 44...47% Ag, 28...32% Cu, 23...27% Zn and 0.01...0.05% Si, 0.01...0.05% Ti, 0.01...0.05 % Mn, having an ultimate tensile strength of 25...45 daN/mm, the yield point of 20...35 daN/mm, the elongation on break of 5...10%, the hardness ranging between 130...145 HB, the melting temperature of 660...750°C, specific conductivity of 25...27% IACS, a wetting angle on copper support of 10...12°. The claimed process starts by dosing the metals with a purity of minimum 99.5% or pre-alloys thereof in amounts according to the charge weight and to the above-mentioned composition, followed by the fusion in an electric induction furnace of a dosed amount of Cu and Ag, there being achieved the increase of the temperature of the metal bath up to 1150-1200°, then there are successively introduced Si, Ti, Mn or the pre-alloys thereof Cu-Si, Cu-Ti and Cu-Mn and when the temperature is lowered down to 850...900° there is also introduced the amount of Zn under a protection flux layer comprising 50% NaCOand 50% NaBO, the temperature is lowered down to 800...850°C when the casting into metal moulds is carried out there resulting semifinished products in the shape of cylindrical bars or plates which are subsequently hot or cold rolled in order to obtain finished products as wires and strips, with deformation degrees of 30...50% between annealings and intermediate annealings at 400...450°C. |
