 Hello everyone. I am Chandrakant Rathod working as assistant professor in mechanical engineering department at Walchand Institute of Technology, Solapur. Today we are going to start a new topic that is introduction to soldering process and its application. At the end of today's lecture, you are able to understand soldering process and its application of soldering process. So coming to the contents, so these are the following topics will be discussed in this lecture that is introduction of soldering, principles of soldering, parameters affecting the soldering process, types of soldering method, working principles, application of soldering and advantages and limitations of soldering process. So now we are going to start introduction of soldering. Soldering is a liquid solid state metal joining process in which the metal parts being joined are not melted while the filler metals used is molten, is in molten condition. The molten metal flow in between the two closely placed surface of the workpiece by capillary action. The base metal is joined by the formation of an alloy or a solid solution of the joint. This process can also be used when the base metal parts are not to be melted and overheated. So there are two different types of soldering that is soft soldering and the hard soldering. So what is mean by soft soldering? Soft soldering where the soldering method with use of tin lead, antonomy and tin lead alloy is called soft soldering. What is mean by hard soldering? So hard soldering is nothing but the process uses soldering always containing silver is called the hard soldering. Watch the video, what is mean by hard soldering? I hope you have written the answer. What is mean by hard soldering means the process uses soldering always containing silver is called hard soldering. So coming to the principles of the soldering, when the atoms of one of the components, components metals of the solder joints with the base metals it forms a solder solid solution. If there is a combination of two or more metals forms the liquid solution then it results in the formation of an inter metallic compounds. In the usual lead tin soldering tin forms an inter metallic compound with the base metals like iron and copper. Usually the wetting ability is associated with the formation of suitable inter metallic compound. However, the excessive formation of these compounds as a result of prolonged heating under high temperature has negative effect on the joint. Hence the joint become brittle and weaker under these conditions. So coming to the parameter affecting the soldering process. The important parameter involved in forming a good solder joint are as follows. First we are going to discuss surface wetting ability, chemical affinity, surface cleanliness, use of flux and application of heat. So we are going to discuss one by one surface wetting ability. For the successful soldering of a metal surface it must be able to get wetted by the solder. For proper wetting action to take place the solder and base metal should have a good liquid solubility between them. So coming to the chemical affinity. It refers to the ease of formation of a solid solution or an inter metallic compound between the base metal and the filler metal. If higher the chemical affinity stronger will be the soldering joint. So now coming to the surface cleanliness. In addition to the chemical affinity the ability of the solder to wet the surface of base metal is also affected by the cleanliness of the surface. Thus metals coating like oxide, paints, dirt, grease etc that should be removed from the work piece if it is not removed then it reduce the wet ability. Coming to the use of flux. So after the cleaning and external thin film of a metallic oxide is formed on the metallic surface which reduce its wet ability this oxide film and dirt can be removed by the use of flux and flux under the hot condition react with the surface coatings dissolves and it forms a slug. So coming to the application of heat. In soldering process the purpose of the heating is to melt the solder and preheat the base metal. A proper amount of preheating ensure effective wetting of the molten solder on the base metal surface. So coming to the types of soldering methods. There are different types of soldering methods are there. First one is soldering iron method torch method hot dip and wave method resistance method furnace and hot plate method induction method and ultrasonic method. So these are the important soldering methods which is used for the joining the two base metals. So coming to the working principles of the soldering the basic steps is in a good soldering operation are as follows. First we are going to discuss the preparation of our design of the soldering joints cleaning of the surface flux application tining and the application of solder. First we are going to discuss the preparation or design of soldering joint. In soldering operation the molten solder flow between two closely placed adjacent surface by capillary action. Thus the closer the parts better is the capillary action and better preparation of solder. Hence parts should be fitted closely so as to fill the space completely with the solder. So coming to the cleaning this cleaning the surface the base metal surface may contains dirt paint grease so that etc which is to be cleaned for the good soldering. If it is present on the work piece or a job so that affects the our joining joints. So coming to the flux application on the cleaned and assembled parts flux is to be applied to form a slag with impurities and protect film of solder from oxidation while applying the flux the parts can be assembled and kept ready for joining. So coming to the tining operation is done to ensure that the surface to be joined are completely vetted by a thin film of soldering. So this helps by a way of deep penetration of the solder into the joints. So coming to the application of solder copper solder bit is traditional tool used in manual soldering it is used as a source of heat for melting the solder on the surface. So coming to the application of soldering soldering is mainly used in electrical circuit we know that in all the electrical boards there are many circuits are there that circuit circuits is created by using the wires. So that wire is connected by using the soldering process so we know that some flux is applied in between the two wire and the heat is applied and then the joint will going to takes place in between the two electrical wire in the electrical circuit. In electrical equipment as we know that laptop, radios and tapes and other electrical equipment so there are many used circuits and motherboards and chips in the motherboards. So to join the chips and electrical wire in the motherboard so we require the soldering. So for that one we will going to use this soldering joining thin sheet metal. So this also used in the joining the thin sheet metals and joining the wires. So as we know that there are many motherboards or boards are there in the electrical equipments so we can join that connection with the wire. So we require the solder to join in between the wire and the motherboard connection. So coming to the advantages and limitations of the soldering. So first we will going to discuss the advantages. So it is simplest and fastest process for joining electrical connection. As we know that we are using this for the joining the electrical connection very minor level joints such as electrical printed boards. So as we know that there are many boards are there in the electrical equipments. So for minor joining we require the soldering process. So join it is also used in the mass production. So as we know that in the industry we are going to use the soldering process for mass productions and the joint whatever the joint which is joined is usually clean. It is also used to join work piece of the different thickness. So there are many different thickness we will going to join by using the soldering process. So coming to the limitations of the soldering process it is not suitable for the structural joints as we process it is only suitable for low strength and thin joints. So wherever the low strength and thin joint is required so this soldering process is used for the joining the two pieces. So it is not suitable for the Karoji environment and it is not suitable for the high temperature wherever the low temperature is there so there we are not going to use this soldering operations. So these are the some references which is used for the this lecture that is founded technology by OP Khanna and manufacturing technology by P N Rao and manufacturing process one by AC Niranjan. Thank you.