Question2.7. Explain tube bow welding and its types. Answer Tube bow welding Tube bow welding is bow welding in which melting occurs due to the heat generated by a contracted bow between a tungsten electrode and a water- cooled snoot. The process uses two inert feasts, one of which forms the bow tube and the other protects the bow tube. padding essence may or may not be added and pressure isn’t typically used. The MIG process is an external guard. In MIG welding, we use an inert gas as a shielding gas. Used to weld carbon, aluminum, nickel,etc. Both thick and thin workpieces can be welded effectively. Principle of tube bow welding Tube bow welding is a reduced bow process. The bow is sealed with a water- cooled small periphery snoot, which compresses the bow, increases its pressure, temperature and intensely heats, therefore perfecting bow stability, bow shape and heat transfer parcels. Types of tube bow welding – transferred bow The bow is formed between an electrode( –) and a water- cooled shrink snoot(). The tube bow emerges from the snoot as a honey. The bow is independent of the workpiece and the workpiece isn’t part of the electrical circuit. Just like an bow honey, it can be moved from one place to another. Unaltered bow tube has a fairly lower energy viscosity than altered bow tube and is used in welding and operations involving ceramic or essence plating. ii. Transferred bow An bow occurs between the electrode( –) and the workpiece(). The transmitted bow has a high energy viscosity and tube spurt haste. thus it’s used to cut and melt essence. To start the neutralize bow, a current limiting resistor is placed in the circuit so that about 50 A flows between the snoot and the electrode, and a airman bow is established between the electrode and the snoot. When the airman bow touches the work, a main current begins to flow between the electrode and the work, therefore kindling the transmitted bow. The airman bow starter is intruded and the airman bow is extinguished as soon as the bow between the electrode and the work begins. The temperature of the reduced tube bow can be between 8000 and 25000 °C. That2.8. Explain the needle bow micro tube welding process. Answer In micro tube welding( MPAW), an bow is formed between the electrode and the workpiece in an inert atmosphere to melt the essence in the common area and a molten weld mass is formed. What makes MPAW unique from other welding processes is that the electrode is placed inside the arsonist body and the gas that forms the tube is separated from the shielding gas envelope. While in other processes, the electrode is exposed to the atmosphere during the process. It has a medium called a airman bow, which is struck between the electrode and the snoot to start the main welding bow. The control bow can be impaired after main charge or kept on all the time. Micro tube bow current range is0.1 A to 15A. Up to with a welding current of0.1 A, the length can be changed up to 10 mm without affecting the stability of the bow. Stiff needle- suchlike arc reduces wandering and deformation. Micro tube bow welding firebugs are available in both homemade and completely automatic modes. Homemade MPAW can generally be operated in any position where completely mechanical MPAW is performed in vertical and vertical position. Generally, a direct current source is used in micro tube bow welding. The welding current of the Micro tube bow can generally vary from0.01 amps to 15 amps. The palpitation function is attained from the power force. The palpitated bow has the capability to produce the loftiest and most accurate weld quality. That2.9. What are the advantages, disadvantages and operations of tube bow welding? Answer Advantages of tube bow welding Arc stability and invariant penetration. Simplified fasteners and confluence root rewelding saved. thick and roughly 6 mm thick corridor can be made completely piercing keyhole welds with a square butt joint. Advance Welding 2- 11 H( ME- Sem- 5) Excellent welding quality. Tube bow welding allows the product ofx-ray quality welds at high pets. Welds roughly partial consistence sword corridor with a square common in one pass without padding material. Disadvantages of tube bow welding Infrared and ultraviolet radiation requires special defensive outfit. Welders need earplugs because of the unwelcome, disturbing and dangerous noise. This process involves further electrical hazards. The process is limited to a essence consistence of over to 25 mm. The consumption of inert gas is high. Applications of tube bow welding Autogenous single- phase andmulti-phase pipe welding. In tube shop operations. Welding of cryogenic, aerospace, high temperature erosion resistant blends and sword rocket motor jackets. Aquatic nuclear channel system. Welding of carbon sword, pristine sword, nickel, bobby
, brass, monel essence, aluminum, titanium,etc. That2.10. Explain submerged bow welding and also state its advantages, disadvantages and operations. Answer Submerged Arc Welding It’s about bow welding, in which emulsion is achieved by hotting
with an electric bow or bends placed between a essence electrode or between the electrode and the work. The bow, electrode tip and molten pool remain fully hidden and the bow unnoticeable after placing the grainy material under the cover. Submerged bow welding principle In the submerged bow welding process, grainy flux and a bare( or bobby
– carpeted) electrode are used rather of the flowing electrode The bow between the electrode and the work is a heat source and remains under the inflow. Flux acts as a guard and protects the molten weld pool from airborne pollutants. The process can besemi-automatic or automatic. Advantages of Submerged Arc Welding The molten flux creates veritably suitable conditions for high current. To weld thicker corridor with deep penetration, high heat intensity can be produced and kept concentrated. Due to the high heat content, significantly advanced welding pets can be used. A high essence deposit can be achieved. Single pass welds can be made in consistence
