Mastering Arc Welding: Techniques, Processes, and Applications

Arc welding is a process where an electric arc is used to generate heat to melt and join metals. The arc is formed between an electrode and the workpiece, creating a region of intense heat that melts the metals at the welding point. When the metals cool, they solidify to form a strong bond.

1. ARC WELDING RAMESH

2. WELDING PROCESS Welding used for making permanent joints Welding is a process of joining two metal work piece by heating them with or without the application of pressure and filler material It is used in the manufacture of automobiles, aircraft frames, railway wagons, machine frames etc., Filler material is used in welding for making welding strong and the composition of filler material is same as the composition of parent metal(work piece)

3. WELDABILITY Weldability of a metal refers to the ability of a material to be get welded. Ex:The wood can not be welded but mild steel can be welded.

4. ARC WELDING ? Arc welding is a type of welding process using an electric arc to create heat to melt and join metals. A power supply creates an electric arc between a consumable or non-consumable electrode and the base material using either direct (DC) or alternating (AC) currents.

5. ARC WELDING CONNECTION

6. How an arc is formed ? The arc is like a flame of intense heat that is generated as the electrical current passes through a highly resistant air gap

7. ARC Welding equipment Equipment to provide electric current 1. Transformer (for A.C) 2. Generator or Rectifier (for D.C) Accessories 1.Electrodes 2.Electrode holder & cables 3.Safety devices 4.Tools

8. CLASSIFICATION SHIELDED METAL ARC WELDING (SMAW) GAS METAL ARC WELDING (GMAW) FLUX-CORED ARC WELDING (FCAW) GAS TUNGSTEN ARC WELDING (GTAW) SUBMERGED ARC WELDING (SAW)

9. RESISTANCE WELDING It generates heat through the resistance of the work piece to the electric current . CLASSIFICATION:- 1.Spot welding 2.Seam welding 3.Projection welding

10. ENERGY BEAM WELDING It uses a beam of high-energy electrons or laser light. CLASSIFICATION :- 1.Electron beam welding (EBW) 2.Laser beam welding (LBW)

11. SOLID-STATE WELDING It joins the materials without melting them. CLASSIFICATION :- 1.Friction Welding 2.Ultrasonic welding 3 .Diffusion welding

12. ARC PHYSICS Arc welding involves the generation of an electric arc between an electrode and the work piece to melt the metals at the welding point . The electric arc is a sustained electrical discharge between two electrodes that produces a high-temperature plasma and intense light.

13. ARC INITIATION The process of starting the electric arc, typically achieved by : Contact Start : Striking the electrode against the work piece. Non-contact Start : Using high-frequency or high-voltage pulses to ionize the air gap. Arc Maintenance : Maintaining the arc requires a consistent supply of electric current and control of the gap between the electrode and the work piece.

14. Electrical Properties of Arc Static Arc Characteristics :- Voltage-Current Relationship : The static arc characteristic curve represents the relationship between the arc voltage and the arc current . Rising Characteristic : Voltage increases with current (seen in short arcs ). Drooping Characteristic : Voltage decreases with current (seen in long arcs).

15. Power Sources and Characteristics Constant Current (CC) Power Sources : Maintain a relatively constant current despite changes in arc length (suitable for SMAW and GTAW ). Constant Voltage (CV) Power Sources : Maintain a constant voltage regardless of arc length (suitable for GMAW and FCAW).

16. Modes of Metal Transfer In arc welding, the transfer of molten metal from the electrode to the work piece occurs in different modes : Short-Circuit Transfer : Metal transfers during short circuits between the electrode and the work piece. Globular Transfer : Large droplets of molten metal transfer across the arc.

17. Spray Transfer : Fine droplets of metal are sprayed across the arc . Pulsed-Spray Transfer : A variation of spray transfer using pulsed current to control droplet size and frequency.

18. Manual Metal Arc Welding (SMAW) Ingredients and Function of Flux Covering Flux Covering : A coating on the electrode that provides multiple functions: Protects the molten metal from atmospheric contamination. Stabilizes the arc. Adds alloying elements. Forms slag to cover the weld bead and protect it during cooling.

19. Types of Electrodes Cellulosic Electrodes : Deep penetration, suitable for vertical and overhead positions . Rutile Electrodes : Easy arc starting and smooth weld bead, used for general-purpose welding. Basic Electrodes : High toughness and crack resistance, used for critical applications.

20. Handling and Storage of Consumables Storage : Electrodes should be stored in a dry, temperature-controlled environment to prevent moisture absorption . Handling : Avoid dropping or damaging electrodes, and use within the manufacturer's recommended time frame after opening.

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