Welding Mr. Wisness. What is welding? Joining two or more pieces of metal together by the fusion...
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Transcript of Welding Mr. Wisness. What is welding? Joining two or more pieces of metal together by the fusion...
Welding
Mr. Wisness
What is welding?
Joining two or more pieces of metal together by the fusion process
Importance of Welding
50 % of Gross National Product of the country is related to welding
Almost everything made of metal is welded
How is welding used in Industry
Railroad freight cars Trans-Alaskan pipeline Elevated storage tanks
for water Patio chairs Sears Tower Automobiles Collision Repair Work
Space Program Airplanes Coffeepots Bridges Furniture Jet Engines Yachts Construction Equipment
Career Opportunities
1. Building Construction 2. Bridge Highway Construction 3. Automotive Industry 4. Ship Building 5. Aircraft Industry 6. Self-Employed Business Owner
How is welding used in Agriculture?
Essentially all farm equipment is welded together– Tractors– Bobcats– Combines– Trailers
Repair and maintenance of buildings and equipment
Types of welding
O xy-ace tylen eW eld in g
S h ie ld ed M eta lA rc W e ld in g
S M A W
G M A WG as M eta l A rc W e ld in g
M IG W eld in gM eta l In e rt G as
Typ es o fw e ld in g w eare g o in g to
d o in th is c lass
Oxy –acetylene welding
Two gases involved– Oxygen– Acetylene
Compound of Carbon and Hydrogen Colorless (but not odorless) Flammable Combined with oxygen produces hottest flame temperature
Equipment used for Oxy-acetylene welding
Acetylene tank, hose and regulator
Oxygen tank, hose and regulator
Welding torch body Cutting assembly with tip Wrenches to fit
connections Safety goggles
Tongs for handling hot metal
Welding table Flint Lighter Coveralls Gloves
MIG Welding
Metal Inert Gas Also known as GMAW
– Gas Metal Arc Welding
Uses a continuous solid wire electrode for filler metal
Uses an externally supplied gas for shielding
Shielded Metal Arc Welding
Stick Welding Flux covering electrode melts during welding
– Forms the gas and slag to shield the arc and molten weld pool.
– Slag must be chipped off the weld bead after welding
TIG Welding
Tungsten Inert Gas Also called Gas Tungsten Arc Welding (GTAW) An arc is formed between a nonconsumable tungsten
electrode and the metal being welded Gas is fed through the torch to shield the electrode and
molten weld pool. If filler wire is used, it is added to the weld pool
separately. Has become a popular choice of welding processes
when high quality, precision welding is required.
Five Basic Joint Types
Butt Corner Edge Lap Tee
Welding Positions
Flat Vertical Overhead Horizontal
Kinds of Welds
Fillet Groove Bead
Welding terms
Weldment– An assembly whose component parts are joined by
welding Joint
– The junction of members or the edges of members that are to be joined or have been joined
Tack weld– A weld made to hold parts of a weldment in proper
alignment until the final welds are made
Welding Terms
Base Metal– The material to be welded, brazed, soldered or cut
Filler Metal– The metal or alloy to be added in making a welded,
brazed or soldered joint
Autogenous– Filler metal is not used
Welding Terms
Coalescence– The growing together or growth into one body of the
materials being welded
Fusion– The melting of metals until the molten portions unite
with each other
Crater– Depression at the end of a weld
Backfire
A loud “pop” which occurs while welding with the oxyacetylene process
Causes may include”– Touching tip against work piece– Flame setting too low– Loose or dirty tip– Damaged seals inside torch
Welding Terms
Electrode– Metal rod which conducts a current from the
electrode holder to the base metal
Arc– The flow of current across a narrow gap
Face– The exposed surface of a fusion weld
Welding Terms
Bead Weld– Made by one pass of the electrode
Pads– The metal plates which have beads running parallel
to each other in such a way that the beads are united with one another to form a solid mass
Bevel– Type of edge preparation
Welding Terms
Consumable Welding Arc Process– A welding process in which
the electrode is consumed in the welding process
Non-consumable Welding Arc Process– Electrode does not melt in
the arc, and filler metal is not carried across the gap
Welding Terms
Flux– Material used to prevent, dissolve, or facilitate
removal of oxides and other surface substances Kerf
– The width of the cut produced during a cutting process
Spatter– The metal globules expelled during metal arc
welding and which do not form a part of the weld
Welding Terms
Penetration– The distance from the original surface of the base
metal to the point at which fusion ceases
Porosity– A condition which is caused by a gas pocket being
trapped in a weld as it solidifies
AWS– American Welding Society
SMAW Benefits
Equipment used is simple, inexpensive, and portable
Electrode provides and regulates its own flux Lower sensitivity to wind and drafts than gas
shielded welding processes All position capability
MIG Welding Benefits
All position capability Higher deposition rates than SMAW Less operator skill required Long welds can be made without starts and
stops Minimal post weld cleaning is required
TIG Welding Benefits
Superior quality welds Welds can be made with or without filler metal Precise control of welding variables (heat) Free of spatter Low distortion
Advantages of Oxy-acetylene welding
Equipment is very portable Relatively inexpensive Can be used in all positions Pool is visible to welder
Welding is fun!
But Safety Always Comes First!