Many of us are well aware of what welding is and what it is used for. There are more than a dozen main types of welding and several types of welding processes, in particular: seam welding, projection, spot. As an example: seam resistance welding allows you to connect metal parts using a seam, hence it has this name. To ensure a reliable connection of the constituent components (elements) of metal structures, a graphical representation of various welding cyclograms is indicated (a general display of what the welding mode is). As practice shows, on the basis of theoretical and practical knowledge, any type of welding has one common structure / basis, so it is of the same type. To get a more accurate answer to the question — what kind of actions take place during the welding process, it should be said about electrical thermal deformation. In this case, we are talking about three stages of the welding sequence diagram.
Stages of the welding sequence:
- The first stage — all uniform processes that do not receive much development, this occurs due to slight deformation when the metal is heated and the relatively low temperature in the welding zone.
- At the second stage, the metal itself expands, and all due to the molten core. With significant thermal conductivity, the heat-affected zone of the metal structure heats up strongly, while it completely changes its own structure (mass transfer in the electrode-part contact).
- The final third stage — the metal core is completely cooled, it forms a single structure with a significant part of residual stresses. The structure of the metal changes only in the near-weld zone, where heat transfer continues to operate. All accompanying processes and the initial properties of the metal are quite amenable to deformation, this can be done by: increasing cooling, increasing or decreasing the current pulse, increased or decreased heating.
With the correct welding mode, eg spot welding, high productivity can be achieved (excellent quality part / material).
Depending on a particular welding process, how correctly it forms the joint of a metal structure, physical processes can be divided into several important categories, these are basic and accompanying ones. The main ones include: heating the metal core (crystallization), plastic deformation of the product, as well as the removal of surface films on a metal base. The category of accompanying physical processes, this list includes: full expansion of the metal (heat deformation), change in the temperature regime / deformation state of a point of the body on the structure of properties of the welded joint, the formation of residual stress and, finally, mass transfer in the electrode-part contact. A typical example of all these processes is projection welding, where the connection takes place at several points at once.
Resistance welding uses ready-made electrodes made of bronze semi-finished products of various forms of supply. Special Materials Company supplies the following bronze alloys for the production of high quality electrodes:
- AERIS 1345 — Russian analogue of BrB2 — CuBe2 alloy
- AERIS 1335 — Russian analogue of BrNBT — CuCoNiBe alloy
- AERIS 1340 — Russian analogue of BrNHK, BrNHK (f) — Alloy CuNiSiCr
- AERIS 1320 — Russian analogue of BrH — Alloy CuCr1
- AERIS 1330 — Russian analogue BrKhTsr, Br1KhTsr, BrKh, BrKh1, BrCr — Alloy CuCr1Zr