The three composite rivet contacts are made of three layers of silver alloy, copper substrate and silver alloy by cold pressing welding principle.Cold pressure welding is a kind of pressure welding, is in the case of no heating, with the help of pressure to produce plastic deformation of the metal, the welding end surface of the oxide film and other impurities out, so that the pure metal pressed to a certain atomic spacing, forming lattice surface, so as to produce a bond between atoms
From the perspective of "Nongzi theory", the main point of view is that the combination between gold and Zhongzi depends on the combination of metal chain in the beginning, which describes the movement of negatively charged electricity into a "cloud "...The "cloud" free reading device moves around the nucleus in a regular manner, thus resulting in the attraction between F. It has been proved in practice that there is mutual attraction between the electron and the nucleus within a certain range. Therefore, if two metal surfaces collide with each other, the distance between the two surfaces should not exceed a few angstroms (A) clearance, this will eliminate the port in resistance, can produce A "cloud", so as to realize the welding [) cold press on mom pick face no heat affected zone and softening zone, thus the welding transverse mechanical strength, electrical properties and corrosion resistance are good, the superiority is the other welding methods pill shaking. Optimum of ten electrical contact materials mainly 4 u, Ag interface gold and other non-ferrous metal, add to suitable for cold press industry. Based on the above analysis, let go of the traditional processing principle of complex coal, adopt efficient and concise cold welding model in the original design.
The 12-steel wire was used as the base material for the three compound fastening contacts, and the end face of the contact head and foot were combined with Ag, in which the silver layer of the head was cold-welded according to the forming principle of the double compound contact.The welding according to the way is two has just been cut down to the two kinds of material of line segments, keep the shear face fresh clean (tile oxidation, organic compound pollution), first used in welding in degrees, of the forging by compound contact again touch head shape requirements of the cavity, USES the cold forging pressure, make the two materials to peripheral expansion ", and causes a type of deformation, and full of cavity, point form to meet the requirements.According to JB 10872 2008 technical Conditions for electric contact of three composite rivets, the minimum expansion ratio of product specifications is 1:1.66.However, it has been proved by production tests for many years that the bonding strength of the composite surface can be satisfied as long as the plastic deformation expansion ratio of the composite end of the two materials is greater than 1:1.4.The structure of the head of the two composite rivet contacts is generally within the range of the expansion ratio: the first part is cylindrical, which cannot meet the requirements of deformation, and the tensioned ratio is 1:1.4. Therefore, it seems impossible for the foot structure to meet the basic requirements
The "ring cutting process" is proposed to make the foot coating: firstly, the composite parts of two materials at the foot of the lamp are amplified and expanded to meet the bonding strength of the welding parts, and then the excess materials are removed
