Fundamentals of Welding

695 views

Published on

Manufacturing Processes

Published in: Automotive, Business, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
695
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
16
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Fundamentals of Welding

  1. 1. MAJU,ISLAMABAD 11/26/2013 0
  2. 2. MANUFACTURING PROCESSES-I PROJECT NAME: WELDING PROCESSES GROUP MEMEBERS: 1 . A B U B A K R AY U B 2 . WAQ A S A S H R A F 3. HAFEEZ-UR-REHMAN 4 . B I L A L J AV E D 5. SALMAN AZIZ 11/26/2013 1
  3. 3. CLASSIFICATION OF ASSEMBLY PROCESSES MAJU,ISLAMABAD 11/26/2013 2
  4. 4. What is Welding? Welding is a materials joining process in which two or more parts are coalesced at their contacting surfaces by a suitable application of heat and/or pressure MAJU,ISLAMABAD 11/26/2013 3
  5. 5. TERMS 1) Filler Material: Facilitate coalescence, Increase bulk and strength. 2) Weldment: The assemblage of parts that are joined by welding is called a weldment. 3) Faying Surfaces: Surfaces in contact or in close proximity that are to be joined. 4) Welding Fixture: Holds and clamps the components in fixed position for welding. 5) Welding positioner: Hold the parts, can also moves the assemblage to the desired position for welding. MAJU,ISLAMABAD 11/26/2013 4
  6. 6. ARC (AW) RESISTANCE (RW) FUSION WELDING TYPES OF WELDING PROCESSES OXYFUEL (OFW) OTHER ELECTRON BEAM LASER BEAM DIFFUSION (DFW) SOLID STATE WELDING FRICTION (FRW) ULTRASONIC (USW) MAJU,ISLAMABAD 11/26/2013 5
  7. 7. V E R S AT I L I T Y O F W E L D I N G The principal applications of welding are: 1. Construction, such as buildings and bridges 2. Piping, pressure vessels, boilers, and storage tanks 3. Shipbuilding 4. Aircraft and Aerospace 5. Automotive and Railroad 6. They can be performed at construction sites, in shipyards, at customers’ plants, and in automotive repair shops MAJU,ISLAMABAD 11/26/2013 6
  8. 8. The Weld Joint: It is the junction of the edges or surfaces of parts that have been joined by welding. Types of Joints • Butt Joint • Corner Joint • Lap Joint • Tee Joint • Edge Joint Types of Welds • Fillet Weld • Groove Weld • Plug Weld • Slot Weld • Spot Weld • Seam Weld • Flange Weld • Surfacing Weld MAJU,ISLAMABAD 11/26/2013 7
  9. 9. (a) butt, (b) corner, (c) lap, (d) tee, and (e) edge Various forms of fillet welds MAJU,ISLAMABAD 11/26/2013 8
  10. 10. Some typical groove welds Plug and Slot Welds MAJU,ISLAMABAD 11/26/2013 9
  11. 11. a) SPOT WELD and b) SEAM WELD MAJU,ISLAMABAD 11/26/2013 10
  12. 12. PHYSICS OF WELDING MAJU,ISLAMABAD 11/26/2013 11
  13. 13. PHYSICAL RELATIONSHIPS There are two physical relationships that allow fusion welding to be performed. “ Power transferred to the work per unit surface area ” Power Density PD = P/A (Watt/mm^2) Physical relationships Heat Balance Equations 11/26/2013 MAJU,ISLAMABAD Hw (net heat used by the welding operation)=Um*V (Joules) 12
  14. 14. EFFECT OF TIME • Inverse Relation (PD is inversely proportion to time of melting) • If power density is too low, the heat is conducted into the work as rapidly as it is added at the surface, and melting never occurs. • The minimum power density required to melt most metals in welding is about 10 W/mm^2. • Differences in the range of PD among different welding processes.(See Table on next slide) MAJU,ISLAMABAD 11/26/2013 13
  15. 15. • For metallurgical reasons, it is desirable to melt the metal with minimum energy, and high power densities are generally preferable. MAJU,ISLAMABAD 11/26/2013 14
  16. 16. Heat required to melt depends upon: • Metal’s volumetric specific heat • The melting point of metal • Metals heat of fusion MAJU,ISLAMABAD 11/26/2013 15
  17. 17.  The unit Energy for melting is given by, Eq # A  Not all the energy Generated by Heat source is used to melt the weld metal MAJU,ISLAMABAD 11/26/2013 16
  18. 18. HEAT BALANCE EQUATION and Heat Transfer Mechanism MAJU,ISLAMABAD 11/26/2013 17
  19. 19. • Heat Energy available for welding is given by: Hw= f 1*f 2*H • f1 and f2 are proportions •H = total Heat generated by the welding process • Heat balance will be (from Eq # A) Hw= Um*V • Rate form RHw=f 1*f 2*RH= Um*Aw*v 11/26/2013 MAJU,ISLAMABAD 18
  20. 20. FUSION WELDED JOINT, ZONES AND GRAIN STRUCTURE Figure (a) MAJU,ISLAMABAD 11/26/2013 19
  21. 21. Figure(b) MAJU,ISLAMABAD 11/26/2013 20
  22. 22. Cont. • Fusion Zone (Completely Melted) • Epitaxial Grain Growth (Atoms from the molten pool solidify on preexisting lattice sites) • Weld Interface (Narrow boundary) • Heat Effected Zone (Welding failures occur) • Unaffected Base Metal (residual stresses) MAJU,ISLAMABAD 11/26/2013 21
  23. 23. 11/26/2013 MAJU,ISLAMABAD 22

×