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

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!