 Hello friends, myself Dr. Narendra Kartikar, Assistant Professor, Department of Mechanical Engineering, Valachandra Institute of Technology, Solapur. Now, we are going to discuss particularly study of brazing. At the end of this lecture or session, student will be able to understand the brazing process and also know where to apply it. The content for this presentation come discussion, introduction, introduction to joining processes, introduction to brazing processes, brazing process description, brazing process types, advantages and disadvantages of brazing process, application of brazing process. In introduction, let us focus on the particularly four basic manufacturing processes. As we know to produce, to manufacture any of the element individually or in the form of an assembly, we required to choose one of the basic manufacturing process like casting, metal forming, joining processes, metal cutting. As we know to form particularly assembly of more than two elements together in a permanent manner, then we have to go with joining process itself. As far as joining processes rather welding process itself, we have to follow the four of the parameters like heat energy, filler material, flux material or pressure. Out of these four parameters, more than two parameters or all four parameters can be used to fulfill the joining process operation. When we are talking about joining the more than two elements together, apart from welding there are two more types of joining methods permanently that is brazing and soldering. In welding as we know the conceptually, the base metal as well as the filler material is converted into the molten form. Then in a molten form itself, the base metal as well as filler material mix together and after solidification, the distinct elements join together in a permanent form whereas in soldering and brazing, the base metal is not going to be convert from solid state to the molten state itself. Soldering and brazing provides the permanent joint to the bond metal pieces. Soldering and brazing process lie some between varying fusion welding and solid state welding. Let us go to the introduction of brazing process. Joining process in which a filler metal is melted and distributed by capillary action between feying surface of metal parts being joined. No melting of base metal occur in the brazing process itself. Only the filler material get converted into the molten form that is it melts. Filler metal liquidous temperature above or greater than 450 degree Celsius but less than the solidest temperature of base metal to be joined. At this stage of this session, rather discussion and presentation, are you able to recall or share some of the parts where different geometries are joined together with the means of brazing process. Enlist such brazed parts which you had seen earlier anywhere in real time. Thank you. I hope that everyone has enlisted their past experience knowledge for the particularly brazing process examples. Brazing process during brazing the base metal of two pieces to be joined is not melted at all. An important requirement is that the filler metal must weight the base metal surfaces to which it is applied. The diffusion or alloying of the filler metal with the base metal place even though the base metal does not reach its solidest temperature. The surfaces to be joined must be chemically cleaned before brazing. However, the fluxes are applied to remove the oxides from the surfaces. Borax is the most widely used flux during the process of brazing. It will dissolve the oxides of most of the common metal itself. Thus, the particularly surfaces are cleaned out. You can look to the two of the images which are self-explanatory help out to learn to know the brazing process itself. Right-side image is the conceptual image which explains how the particularly brazing took place. The right-side image is the real-time photograph of brazing process itself. The filler metal is drawn through the joint to create this bond is capillary action. In a brazing operation, you are applying heat broadly to the base metal. That means, heating took place to the base metal itself, the base metal which are to be joined. The filler metal is then brought near into the contact with the heated part. It is melted instantaneously, instantly by the heat in the base metal and drawn by capillary action completely through the joint. Brazing process, varieties of types will see one by one. Torch brazing, it is the most widely used brazing method. You can look at to the particular conceptual figure where the torch delivers the heat energy in the form of flame and conceptually the rod is shown over there which represent the filler material itself. Heat is produced generally by burning a mixture of oxyacetylene gas as in the case of gas welding itself. A carbonizing flame is suitable for this purpose as it produces sufficiently high temperature needed for brazing. You can look at to the image to know more about how the torch brazing could carried out. Next process, furnace brazing. You can see the setup where furnace is there from particularly one of its end rather side. The jobs which are pre-placed in a pre-assembled condition with a flux and filler material are arranged and passed through the particularly conveyor. Then to the other side the brazed joints ready parts can be taken out. It is suitable for brazing large number of small or medium parts. Usually, brazing filler metal in the granule or powder form or as a strip is placed at the joint and then assembly is placed in the furnace and heated. Large number of small parts can be accommodated in a furnace and simultaneously all are brazed together. Carbon brazing a process that uses electrical resistance of workpiece and high frequency current induced in the same as the source of heat energy. Heat generated through the same can be used for brazing purpose. The parts are pre-loaded with the filler metal and placed in a high-frequency AC field. You can see the particularly conceptual figure with which the brazing process induction brazing can be cleared out. The setup consists the circuit with a transformer workpiece which is placed inside the coil. Deep brazing assembled parts are typically dipped in a heated chemical bath which serve as both thick fluxing agent and heat source to melt pre-applied filler material. You can see the setup where particularly bath of particularly molten flux is there. Before brazing and after brazing you can see the assembly of two elements together. In the coil bath brazing sheets is connected to the particularly container and after taking out you can look at to the there brazed joint is seen to the in between container and holder handles. Advantages of brazing process any metals can be joined including dissimilar metal. This is the most important advantage as compared to the welding one. Brazing brazing methods can be performed quickly. Brazing can be applied to joint thin walled parts that cannot be welded at all. In general less heat and power are required than in fusion welding. Some of the disadvantages of brazing process joint strength is generally less than that of the welded joint. Although strength of a good brazed joint is greater than that of a filler metal it is likely to be less than that of base metal. High service temperature may weaken a brazed joint. The color of metal in brazed joint may not match the color of the base metal part. Applications, automotive that is joining the tubes and pipes, electrical equipment joining the wires and cables, cutting tool brazing cemented carbide inserts to the shanks, jewelry, chemical process industry, plumbing and heating, contractor joint, metal pipes and tubes by the brazing, repair and maintenance work. Some of the references are introduction to basic manufacturing process and workshop technology Rajendra Singh, a textbook of workshop technology manufacturing process as Khurmigupta, NPTEL, study material and so on.