advance welding & brazing technology
TRANSCRIPT
Generic view on Manufacturing Processes
Manufacturing Processes
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Shaping Processes
Surface Processing Operation
Particulate Processing
Material Removal
Deformation Processes
Solidification Processes
Processing Operation
Assembly Operation
Property Enhancing Processes
Coating & deposition Pro.
Cleaning & surface Treat..
Heat Treatment
Adhesive bonding
Mechanical Testing
Permanent Joining Processes
Permanent Fastening
Threaded fasteners
Brazing & Soldering
Welding
WELDING
◦ Welding is a materials joining process which producescoalescence of materials by heating them to suitabletemperatures with or without the application of pressure orby the application of pressure alone, and with or without theuse of filler material.
◦ Welding is used for making permanent joints.
◦ It is used in the manufacture of automobile bodies, aircraftframes, railway wagons, machine frames, structural works,tanks, furniture, boilers, general repair work and shipbuilding.
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TYPES
Plastic Welding or Pressure Welding
The piece of metal to be joined are heated to aplastic state and forced together by external pressure
Ex: Resistance welding
Fusion Welding or Non-Pressure Welding
The material at the joint is heated to a molten stateand allowed to solidify
Ex: Gas welding, Arc welding
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Classification of welding processes:
(i). Arc welding
Carbon arc
Metal arc
Metal inert gas
Tungsten inert gas
Plasma arc
Submerged arc
Electro-slag
(ii). Gas Welding
Oxy-acetylene
Air-acetylene
Oxy-hydrogen
(iv)Thermite Welding
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(iii). Resistance WeldingButtSpotSeamProjectionPercussion
(v)Solid State Welding
Friction
Ultrasonic
Diffusion
Explosive
(vi)Newer Welding
Electron-beam
Laser
(vii)Related Process
Oxy-acetylene cutting
Arc cutting
Hard facing
Brazing
Soldering
Equipments:
A welding generator (D.C.) or Transformer (A.C.)
Two cables- one for work and one for electrode
Electrode holder
Electrode
Protective shield
Gloves
Wire brush
Chipping hammer
Goggles
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Weld defects
Geometric
•Misalignment
•Concavity or Convexity
•Excessive Reinforcement
•Improper Reinforcement
•Burn-through
•Backing left on
•Incomplete Penetration
•Surface Irregularities
Other
•Arc Strikes
•Slag Inclusions
•Tungsten Inclusions
•Oxide Films
•Spatter
•Arc Craters
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•Lack of Fusion
•Shrinkage
•Overlap
•Undercut
Brazing
It is a low temperature joining process. It is performed attemperatures above 427ºC and it generally affords strengthscomparable to those of the metal which it joins.
It is low temperature in that it is done below the meltingpoint of the base metal. It is achieved by diffusion without fusion(melting) of the base.
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Brazing can be classified as
Torch brazing
Dip brazing
Furnace brazing
Induction brazing
BRAZING
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Brazing methods
(a) Torch and filler rods
(b) Ring of filler metal
at entrance of Gap
(c) Foil of filler metal
between flat part
surfaces
VARIOUS BRAZING JOINTS
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(a) Conventional butt
(b) Scarf joint
(c) Stepped joint
(d) Increased crossest
ion
(a)Conventional Lap
(b) Cylindrical part
(c) Sandwiched part
(d) Use of sleeve
Advantages & Disadvantages
Advantages
Dissimilar metals which can not be welded can be joined by brazing
Very thin metals can be joined
Metals with different thickness can be joined easily
In brazing thermal stresses are not produced in the work piece. Hence there is no distortion
Using this process, carbides tips are brazed on the steel tool holders
Disadvantages
Brazed joints have lesser strength compared to welding
Joint preparation cost is more
Can be used for thin sheet metal sections
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Recent Trend of Welding Technology Development and Applications
by OI Kenji et.Al.
Status of Technology Development in Automotive Field.
Status of Technical Development in Plate and Steel Pipe Fields.
Current Status of Basic Technology Development.
Trends in Welding Automation Technologies in Actual Fabrication.
o Unmanned Robot Welding System.
o Narrow Gap Welding of Heavy Plates.
o Field Girth Welding of Gas Pipelines.
o Rail Welding Technologies.
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Trends in Welding Automation Technologies in Actual Fabrication.
Unmanned Robot Welding System:
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Trends in Welding Automation Technologies in Actual Fabrication.
Narrow Gap Welding of Heavy Plates:
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Trends in Welding Automation Technologies in Actual Fabrication.
Field Girth Welding of Gas Pipeline:
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Trends in Welding Automation Technologies in Actual Fabrication.
Rail Welding Technologies: