1. Shielded Metal Arc Welding Joints and Passes
Butt joint, Corner joint, Lap joint Tee joint, Root pass, Hot pass, Filler pass, Cover pass

2. PREP FOR 1ST PROJECT!
The know how behind how to do your first project!
Joints , Welds, And Passes

3. Short welds spaced at intervals to join parts to whole in process of assembly before welding
Must be strong
Hold part in position
Able to resist stress when expansion and contraction occur during welding
Number and size of tack welds depend upon thickness of plate, length of seam, and amount of cold working to be done
Tack Welds

4. Tack Welds Use more heat for tack welding than for major welding
Must have good fusion and good root penetration
Flat and smooth
American Welding Society
Tack Welds
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5. Position is important as metal heats and cools it expands and contracts
Example from P.D Session
American Welding Society
Tack Welds
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6. Weld made by moving weld pool along intended path in straight line
Fast cooling rates because of faster travel speed
Can impact grain structure and affect distortion level
Stringer Bead
American Welding Society, Welding Inspection Technology, 4th ed.,
p. 4-27, Fig. 4.32, 2000.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

7. Cavity-type discontinuities (pores) formed by gas entrapment during solidification
Discontinuities are spherical and may be elongated
Usually caused by contamination of filler metal or base metal or improper gas shielding
Not considered as severe concern as cracks or incomplete fusion
Porosity
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8. Four Weld Types Groove weld Plug (slot) weld Bead (surface) weld
Fillet weld
Groove weld
Plug (slot) weld
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9. Bead Welds Also called surface welds
Single-pass deposits of weld metal
Used to build up pad of metal and to replace metal on worn surfaces
Bead Welds
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10. Consist of one or more beads deposited in right angle formed by two plates
Take triangular cross section due to location placed in weld joint
Used for lap joints, T-joints, and open corner joints
Weld symbol takes same triangular shape as weld
Fillet Welds
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11. Fillet Weld Important aspect is its profile KNOW TERMS**
American Welding Society, Welding Inspection Technology, 4th ed., p. 4-24, Fig. 4.22, 2000
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

12. Fillet Welds Most common weld used in industry
As strong or stronger than base metal if weld correct size and proper welding techniques used
Contour is shape of face of weld
Flat
Convex
Concave
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13. Remember: A weld or weld joint is no stronger than its weakest point.
Under Welded
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14. Fillet and groove welds usually made along full length of joint
Sometimes full strength can be achieved by welding a portion of joint
Effective length of fillet weld measured as overall length of full-size fillet weld
Start and stop of weld must be allowed for
Not square, so allowance made when measuring
Space between welds determined by center-to-center distance of weld which is called pitch
Weld Length

15. area = weld length x weld size
Easily calculated
Important to determine how much stress joint can take
area = weld length x weld size
Safety margins are built in to ensure the weld is able to withstand the load.
Weld Area and Stress

16. Groove Welds Consist of one or more beads deposited in groove
Used for butt joints
Unprepared with square edges
Prepared with bevel or J-groove
If both members prepared same, take shape of V or U and named V-groove or U-groove butt joint
Weld applicable on both plate and pipe
Groove Welds
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17. Groove Welds
American Welding Society
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

18. Activity
Form joints with pieces of wood or metal and draw

19. Square Butt Joint
Made by tack welding two flat pieces of plate together
Root Opening/Gap – Space between the plates

20. Edge Weld Made by placing edges of the weld evenly
Metal held together by clamp with no openings
Weld should equal the thickness of the plate, have build up
Weld bead equal to thickness of joint (usually tack first)

21. Edge Weld

22. Outside Corner Joint
Placing plates at 90˚ to each other with edges forming V-Groove
May or may not have slight root opening left between plate edges
Weld bead should completely fill V-Groove formed by the plates and may be slightly convexted

23. Outside Corner Joint

24. Outside Corner Joint

25. Lap Joint (Project #2) Made by overlapping the edges of two plates
Can be welded on one or both sides of joint with fillet welds
Build up of weld should equal the thickness of the plate

26. Lap Joint (Project #2)
Penetration on lap joints does not improve strength
Complete fusion is required – root must be melted for fusion

27. Lap Joint (Project #2)
Very important to use tack welds to hold in place and clean slag after welds

28. Lap Joint (Project #2)

29. Lap Joint (Project #2)

30. Tee Joint
Tack welding one piece of metal to another piece of metal at a right angle
Important to place tack welds correctly
PD EXAMPLE
Remove slag from tack welds

31. Tee Joint
Watch heat and strength

32. Root Pass First weld bead of a multi pass weld
Fuses two parts of metal together and establishes depth of weld metal penetration
Essential for a good
weld

33. Root Pass
May or may not use backing strip

34. Root Pass
Terms to know for project

35. Root Pass
Ideal root pass

36. Root Pass
Our project (except backing plate)

37. Hot Pass
Surface of root pass may be irregular, have undercut, overlap, slag inclusions or other defects
A way to clean out trapped slag and make the root pass more uniform

38. Hot Pass
Uses a higher-than-normal amperage setting and a fast travel rate to reshape the bead and burn out the trapped slag.
Can be made after chipping away slag and cleaning with wire brush

39. Filler Pass Used after root pass in completed and has been cleaned
Groove is filled up with beads = Filler passes
“Fills up” Area to be welded

40. ****** VERY IMPORTANT FOR****** PROJECT #1
Filler Pass
Use stringer beads
Beads must overlap each other enough so the finished bead is smooth
Must clean bead before doing next pass
****** VERY IMPORTANT FOR****** PROJECT #1

41. Filler Pass
WILL BE DOING THIS ON PROJECT

42. Cover Pass Last bead on a multi-pass weld = Cover Pass
Important to keep it clean and neat looking because most welds have visual inspection
Should be free from defects (undercut, overlap, porosity, slag inclusions)

43. Cover Pass
No more than 1/8th the groove opening

44. Project #1

45. Project #1

46. Project #1
PLATE PREPARATION

47. Project #1

48. Project #1