Basics of Welding (ARC, TIG, MIG)- Techshore Institute
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The document provides an overview of various welding techniques, including arc welding and shielded metal arc welding (SMAW), detailing processes, equipment setup, and safety precautions. It covers types of welding, welding positions, common weldable metals, and the importance of welding in everyday applications. Additionally, the document discusses wear types and degradation modes relevant to engineering systems.
Basics of Welding (ARC, TIG, MIG)- Techshore Institute
- 1. Basics Of Welding Techshore Institute (Top Welding Institute in Kerala)
- 2. Welding • Welding is a process of joining metals * With the application of heat, *With or without the application of pressure, * With or without the application of filler metal to form a metallurgical joint.
- 3. Types of Welding Types of Welding Fusion Fusion • SMAW • Gas / Brazing • TIG • GMAW(MIG/MAG) • FCAW • SAW Non-Fusion Non-Fusion • Forge Welding • Resistance Welding • Thermal Spraying • Electron beam welding. • Laser beam welding. • Soldering
- 4. Types of Joints • There are 5 types of joints …
- 5. Fillet and Groove Welds • Groove and fillet welds can be made on many types of joints
- 6. What are Welding Positions? • There are various positions that a weld can be made in:
- 7. Why is Welding Important? • Many things around us are welded … • Pipelines that bring fresh water • Towers that carry electricity to houses • Cars and buses that take people where they need to go
- 8. Can All Metals Be Welded? • Most metals can be welded, but not all • The three most common weldable metals include: • Mild Steel - inexpensive and strong • Stainless Steel – does not rust • Aluminum – does not rust and is light weight Mild steel Stainless Steel Aluminum
- 9. Arc Welding
- 10. What is Arc Welding? • Arc welding is most commonly used to join two pieces of metal • The welder creates an electric arc that melts the base metals and filler metal (consumable) together so that they all fuse into one solid piece of metal Steel Pipe – Tack Welded Root Pass or “Stringer Bead” Final weld after several beads are made
- 11. Basic Steps of Arc Welding • Prepare the base materials: remove paint and rust • Choose the right welding process • Choose the right filler material • Assess and comply with safety requirements • Use proper welding techniques and be sure to protect the molten puddle from contaminants in the air • Inspect the weld
- 12. The Arc Welding Circuit • The electricity flows from the power source, through the electrode and across the arc, through the base material to the work lead and back to the power source
- 13. Basic Electricity • Voltage – The electrical potential or pressure that causes current to flow • Measured in Volts • Current – The movement of charged particles in a specific direction • Measured in Amps • Polarity • DC- (Direct Current Electrode Negative) • DC+ (Direct Current Electrode Positive) • AC (Alternating Current) DC+ DC - AC
- 14. SMAW welding
- 15. SMAW Principles • The American Welding Society defines SMAW as Shielded Metal Arc Welding • SMAW: • Is commonly known as ‘Stick’ welding or manual arc welding • Is the most widely used arc welding process in the world • Can be used to weld most common metals and alloys
- 16. SMAW Welding Circuit • Current flows through the electrode cable, to the electrode holder, through the electrode, and across the arc. • On the work side of the arc, the current flows through the base material to the work clamp and back to the welding machine.
- 17. SMAW Process Let’s take a little closer look at the SMAW process… 1 Travel direction Electrode Arc 2 Weld Puddle 3 Shielding Gas 4 Solidified Weld Metal 5 Slag 6
- 18. 1- The Electrode • Is a consumable - it gets melted during the welding process • Is composed of two parts • Core Rod (Metal Filler) Carries welding current Becomes part of the weld • Flux Coating Produces a shielding gas Can provide additional filler Forms a slag
- 19. 2- The Arc • An arc occurs when the electrode comes in contact with the work-piece and completes the circuit … like turning on a light! • The electric arc is established in the space between the end of the electrode and the work • The arc reaches temperatures of 10,000°F which melts the electrode and base material Can you identify the weld joint and position being used?
- 20. 3- Weld Puddle • As the core rod, flux coating, and work pieces heat up and melt, they form a pool of molten material called a weld puddle • The weld puddle is what a welder watches and manipulates while welding 1/8” E6013 at 125 Amps AC
- 21. 4- Shielding Gas • A shielding gas is formed when the flux coating melts. • This protects the weld puddle from the atmosphere preventing contamination during the molten state The shielding gas protects the molten puddle from the atmosphere while stabilizing the arc 2 3 Shielding Gas 4
- 22. 5- Solidified Weld Metal • As the molten weld puddle solidifies, it forms a joint or connection between two pieces of base material • When done properly on steel, it results in a weld stronger than the surrounding base metal
- 23. 6- Slag • Slag is a combination of the flux coating and impurities from the base metal that float to the surface of the weld. • Slag quickly solidifies to form a solid coating • The slag also slows the cooling rate of the weld • The slag can be chipped away and cleaned with a wire brush when hard This welder chips the slag off of a weld during the repair of railroad tracks
- 24. Application Activity The electrode The arc Weld puddle Shielding gas Solidified weld metal Slag 1 2 3 4 5 6 Let’s review the SMW process … • 1 = • 2 = • 3 = • 4 = • 5 = • 6 =
- 25. SMAW Equipment Set Up 1. Turn power supply on 2. Connect work clamp 3. Select electrode a. Type b. Diameter 4. Adjust output a. Polarity b. Amperage 6. Insert electrode into electrode holder
- 26. SMAW Process Variables • Settings on the machine • Polarity : AC, DC+, DC- • Amperage Output • Operator Controlled Variables • Work Angle • Travel Angle • Arc Length • Travel Speed A straight AC machine will not have a polarity switch like this AC/DC machine
- 27. Striking an Arc • To begin the SMAW Process, you must first strike an arc. This can be done using one of the following techniques: • Scratch start – scratch the electrode on the base metal like a match • Tap Start – tap the rod against the base metal
- 28. Work Angle • The work angle is the angle between the electrode and the work as depicted on the left • Work angles can vary depending on the position the weld is being made in 90°
- 29. Travel Angle • Also commonly called Lead Angle • The travel (lead) angle is the angle between the electrode and the plane perpendicular to the weld axis 20-30°
- 30. Arc Length • After striking the arc, maintain a 1/8” distance between the electrode and the workpiece • If the arc length becomes too short, the electrode will get stuck to the workpiece or ‘short out’ • If the arc length becomes too long; spatter, undercut, and porosity can occur Arc Length = 1/8”
- 31. Travel Speed • The travel speed is the speed at which the electrode moves along the base material while welding • Too fast of a travel speed results in a ropey or convex weld • Too slow of a travel speed results in a wide weld with an excessive metal deposit The travel speed impacts the shape of the bead. End of Weld
- 32. Restarting a Bead • Here is the proper technique for restarting a weld: 1. Strike Arc Here 2. Move Electrode to Crown of Crater 3. Resume Forward Travel
- 33. Advantages of SMAW • Low initial cost • Portable • Easy to use outdoors • All position capabilities • Easy to change between many base materials What safety precautions should be taken by these welders?
- 34. Limitations of SMAW • Lower consumable efficiency • Difficult to weld very thin materials • Frequent restarts • Lower operating factor • Higher operator skill required for SMAW than some other processes Building a barge in a large shipyard
- 36. WEAR “LOSS OF MATERIAL” CAUSED IN AN ENGINEERING SYSYEM.
- 37. TYPES OF WEAR PRIMARY • FRICTION • ABRASION • IMPACT SECONDARY • CAVITAION • CORROSION • HEAT • EROSION
- 38. FRICTION • FRICTIONAL WEAR IS CAUSED BY MOVEMENT OF ONE METALLIC SURFACE OVER THE OTHER CAUSING LOCALISED MATERIAL LOSS. • NO ABRASIVE MATERILA IS INVOLVED. • EXAMPLES : SHAFT JOURNALS, BEARINGS
- 39. ABRASION • LOSS OF MATERIAL FROM A PART CAUSED BY THE ACTION OF HARD FOREIGN MATERIAL IN MOTION OR UNDER LOAD. Ex :Raw Mill roller, Chutes etc
- 40. TYPES OF ABRASION • GOUGING : Large coarse abrasives strike the surface and remove large amount of material. Ex: Chutes. • HIGH STRESS : Wear caused by crushing of abrasive material between metal parts. High stress abrasion. Ex: Grinding rollers.. • LOW STRESS: Small abrasive parfticles move rapidly over the part. Low stress abrasion. Ex : I D Fans.
- 41. IMPACT • WEAR DUE TO IMPACT IS THE RESULT OF SUCCESSIVE SHOCK LOADS CAUSED BY AN OBJECT STRIKING AGAINST AN OTHER AND CAUSING LOCALISED COMPRESSION, DEFORMATION, CRACKING, FLAKING OR FATIGUE. • Ex: Impactor arms, hammer crusher.
- 42. EROSION • WEAR CAUSED BY FINE ABRASIVES CARRIED IN A HIGH VELOCITY FLUID STREAM • Ex: Pumps, ID Fans
- 43. HEAT DEGRADATION MODES • WARPAGE/DISTORTION • MATERIAL SOFTENING • MATERIAL EMBRITTLEMENT • OXIDATION/SCALING • THERMAL CRACKING • THERMAL SHOCK • THERMAL FATIGUE Ex: Cooler plates in Cement Kiln.
- 44. CORROSION • RESULT OF CHEMICAL OR ELECTROCHEMICAL ACTION OF ENVIRONMENT ON THE BASE METAL. Ex: Pumps, Valves, Screw Conveyors
- 45. ELECTRODE - WORK PIECE + + - PENETRATION CONCENTRATION OF HEAT MORE AT ELECTRODE SHALLOW PENETRATION LESS DISTORTION MORE HEAT GENERATED AT WORK PIECE DEEPER PENETRATION CLEANSING ACTION ON WORK PIECE Selection of Polarity
- 47. IDENTIFICATION FOR CI • SHAPE • CHIP TEST • SPARK TEST • SOUND TEST • TAB TEST – TESTING WELDABILITY OF JOB
- 48. BRASS Vs BRONZE BRASS BRONZE ALLOY ZINC & COPPER ALLOY TIN & COPPER MALLEABLE HARD & BRITTLE USED UNDER STRESS CORROSION RESISTANT GOLDEN COPPER
- 50. GMAW Components • Let’s look a little closer at the GMAW process Travel direction Electrode 1 Arc 2 Weld Puddle 3 Shielding Gas 4 5 Solidified Weld Metal Generally, drag on thin sheet metal and push on thicker materials
- 51. Thank You For more information visit our Website www.techshore.com
Editor's Notes
- #9: SECTION OVERVIEW: Section Overviews are provided on the introductory slides at the front of each topical area to explain the intended use for the slides included in the section. Slide numbers are included on the Section Overview slides for easy reference when preparing for delivery of the slide content. TEACHER NOTES: Teacher Notes are included on the Section Overview slides as a reference tool when making class preparations. Suggested Activities are included for teachers to use to help students gain practical experience with the welding content. However, these are designed to be supplemented by each teacher based on local program needs. Slides have been developed to incorporate content information regarding performance standards from the American Welding Society (AWS) and the National Academic Standards for English, Science, and Math.
- #50: SECTION OVERVIEW: This slide is meant to start generating conversation and thoughts about content to be covered in this lesson. TEACHER NOTES: Bulleted information on topical areas is provided to lead class discussion on areas which are to be covered in the training.