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Smaw welding process

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Welding Process

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Smaw welding process

  1. 1. SMAW Welding Techniques
  2. 2. Weld Bead • A weld resulting from a pass Stringer Bead Weave Bead
  3. 3. Passes • Weld Pass - A single progression of welding along a joint. The result of a pass is a weld bead or layer
  4. 4. Root Pass Hot Pass Fill Pass Cover Pass
  5. 5. Techniques • Stringer (drag) (whip) • Weave – Circles – crescent – zig zag – box weave – double J
  6. 6. Progression (vertical) • Up – deeper penetration – Higher deposit rate (lb/hr) – Use near 90 degree travel angle or slightly up • Down – faster (point to point) – less penetration for thin metal – less dilution – Use steep grag angle
  7. 7. Travel Speed • Stay on the leading edge of the puddle
  8. 8. Flat Position • Fillet/Groove - stringer or weave, split bead or wide weave
  9. 9. Horizontal • Fillet/Groove - stringers (small weave may be used in tight place) • Bead Placement - bottom to top
  10. 10. Vertical • Fillet/Groove - weave (or whip but not straight stringers) • Root pass 6010 whip • Root pass 7018 straight stringer or weave (open closed)
  11. 11. Overhead • Same as horizontal for Fillets • 6010 open root whip for flat face and keyhole control • 7018’s stringers • OH Butt Joints can be stringers or weaves
  12. 12. Dimensions • Reinforcement -ASME flush 1/16 AWS flush 1/8 discuss keyholeing, metallic backing, nonmetallic backing, partial penetration, root openings, root faces, tacking, tack grinding, fast freeze, and fill freeze • Fill -as many as needed 1/8 per pass flat overload 3/16 vertical • Cover -flush 1/16 high, 1/16 past edge
  13. 13. 600 included angle Root faces Tacking Feather Tacks Butt Joint Preperation 1/16-1/8 (Joints without backing)
  14. 14. Open Root Technique • Use root opening to allow increase in amperage for smoother welding • Whip backwards for penetration • Whip forwards to reduce penetration • Do Not Weave a root pass. • Maintain a short arc gap • Stay slightly in front of the puddle at all times. Use the keyholing technique.
  15. 15. Root faces - 0 450 included angle Remove all mill scales and rust Tacking - not in groove Tack away from coupon area. Flush on backing Butt Joint Preperation (With Backing)
  16. 16. Welding grooves with Backing • Keep the root opening wide • Make the root pass in one bead • Avoid tight areas at the weld toes
  17. 17. Restarts •Stagger all starts and stops or use run-on, run-off tabs •Feather all restarts & start on top, or start in front and remelt •Don’t restart in a coupon area. •Also stagger all beads on a single pass. •Use a longer arc length when starting a weld. Compare interpass grinding techniques vs. techniques for no interpass grinding.
  18. 18. Craters • Fill craters by reversing direction at the weld end • Use a short arc length to control heat.
  19. 19. Electrode Work Angles 450 300 700
  20. 20. work angle (transverse angle) • middle of joint • directs heat between sides • may need to direct more on heavy plate
  21. 21. Transverse Angle Effects
  22. 22. Drag Angle increases Penetration Increases crown height Push Angle gives shallow penetration, and flattens out the weld surface. Electrode Travel Angles
  23. 23. Electrode (arc) Placement Current takes the path of least resistance. Therefore, the arc, and resulting weld, will go where the electrode end is closest to, NOT NECESSARILY IN THE DIRECTION THE ELECTRODE IS POINTING
  24. 24. Arc Length •Longer arc lengths = increased puddle heat, flatter welds, deeper penetration •Shorter arc lengths = less puddle heat, flatter welds, less penetration •Use arc length to control puddle size, penetration, and burn through. •Normal arc length is 1/16” - 1/8” •Use a slightly longer arc length during a start or restart.
  25. 25. Helpful Tips •Clean your Welding Hood lens •Drape the cable over your shoulder or knee •Get Comfortable •Watch the puddle, not the arc •Concentrate on steady travel speed and arc length
  26. 26. SMAW Machine Setup • DCEP (also called Direct Current Reverse Polarity) • 77 - 150 Amp Range • #5 fine amperage setting (approximately 110 amps) • Connect work lead • Set for Constant Current (Variable Voltage)
  27. 27. Amperage Calculations Range: 77 - 150 Fine tune dial: 0 - 10 Desired amperage: 105 amps 150 - 77 = 73 73 / 10 = 7.3 7.3 x 6 = 43.8 43.8 + 77 = 120.8 150 - 77 = 73 73 / 10 = 7.3 105 - 77 = 28 28 / 7.3 = 3.836 Range: 77 - 150 fine tune dial: 0 - 10 dial set at: 6
  28. 28. Do SMAW Pipe Welding Techniques Lecture Now

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