Subject Name: MANUFACTURING PROCESS Subject Code: 10AE35 Prepared By: RAVISHANKAR. M & RADHAKRISHNAN.P Department: AERONAUTICAL ENGINEERING Date 11/09/2014 9/16/2018
Topic details Principles of soldering and brazing Parameters involved and mechanism and different types of soldering and brazing methods Inspection methods used for inspection of casting and welding. Visual, magnetic particle, fluorescent particle, ultrasonic, radiography, eddy current, holography methods of inspection. 9/16/2018
Soldering and brazing is essentially a welding process done at lower temperature where the base metal or work piece doesn’t undergo melting and soldification. If the joining process done above 450 degree Celsius but below 650 degree Celsius it is brazing. If the temperature is less than 450 degree Celsius it is referred to as soldering. TYPES OF BRAZING Torch brazing Furnace brazing Induction brazing Resistance brazing Dip brazing Salt bath brazing 9/16/2018
TORCH BRAZING 9/16/2018
FURNACE BRAZING (CONVEYOR TYPE) 9/16/2018
TYPES OF SOLDERING JOINTS 9/16/2018
WETTABILITY PRINCIPLE 9/16/2018
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Gas torch equipment 9/16/2018
The flame produced in combustion of oxygen and acetylene is about 3200 degree Celsius. Different applications require different flame which can be obtained by regulating the gas flow Three types of flames can be produced. NEUTRAL FLAME [OXYGEN:ACETYLENE :: 1:1] The gases are in equal proportions. Temperature is about 3260 degree Celsius. Flame light blue in colour. Blue flame is surrounded by outer flame produced by combination of oxygen and carbon monoxide, hydrogen in the inner zone. This flame type does not produce any chemical change in molten metal. Used for welding mild steel, cast iron, aluminium, copper and stainless steel. OXIDIZING FLAME [OXYGEN:ACETYLENE :: 1.5:1] After establishing neutral flame, the oxygen content is increased. The resulting flame is oxidizing in nature. Flame small short cone, dark blue in colour and more pointed than in the neutral flame. Outer envelope much shorter than the first. Temperature is about 3840 degree Celcius. Excess oxygen tends to combine with metals to form hard, brittle low strength oxides. Limited use in welding. Slightly oxidizing flame is used in welding copper base alloys, zinc base alloys. Wherein preferential oxidation of one of the elements provides a protective layer. 9/16/2018
REDUCING FLAME [OXYGEN:ACETYLENE :: 1:1.5] After neutral flame establishment, acetylene gas amount is increased. The resulting flame is reducing in nature. Outer flame envelope is longer than that of neutral flame and is usually much brighter. A reducing flame does not completely consume the available carbon. Therefore the temperature is lower and unconsumed carbon is forced into the molten metal. A reducing flame ensures the absence of oxidation, metals that absorbs carbon should not be welded with this flame. Non ferrous metals, high carbon steels can be welded with this flame. A carburizing flame contains excess acetylene than a reducing flame. 9/16/2018
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Applications Joining thin sections Most of ferrous and non ferrous metals can be gas welded. Automobile and aircraft industries in sheet metal joining. Types of welding Gas welding can be carried out in two ways namely, Leftward/Forward welding Rightward/Backward welding 9/16/2018
ARC WELDING Electric arc is used as the heat source An electric arc is a continuous stream of electrons flowing between two electrodes into a medium. 9/16/2018
ARC WELDING PARAMETERS Arc current Arc length Electrode diameter Shielding gases Welding time CLASSIFICATION OF ARC WELDING Flux welded arc welding TIG/MIG welding Submerged arc welding Resistance welding Special welding methods Laser welding Atomic Hydrogen welding Plasma welding Thermit welding 9/16/2018
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SUBMERGED WELDING 9/16/2018