Welding Drawings

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Engineering Drawing and Design
Seventh Edition
Chapter 18
Welding Drawings
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18-1 Designing for welding

• The primary importance of welding is to unite
  various pieces of metal so that they will operate
  as a unit structure to support the loads to be
  carried
• Welding processes include arc welding, gas
  welding, and resistance welding (40 total
  processes exist)

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Gas Arc Welding

• Most common form is oxyacetylene welding gets
  heat from the burning of flammable gases. It is
  slow compared to other modern welding methods so
  is used primarily for repair maintenance
• Arc welding is the major industrial welding
  process-heat is generated by an electric arc
  struck between a welding electrode, or rod, and
  the workpiece. The arc is hot and melting and
  solidification of the weld metal occurs rapidly.

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Resistance welding

• Widely used especially for mass production work
• Heat is created from resistance losses as a high
  amperage current is sent across a joint between 2
  mating surfaces

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Plug welding

• A plug weld refers to joining two pieces by
  welding through a hold in one of the pieces

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WELDING DRAWINGS
BASIC WELDING JOINTS
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WELDING DRAWINGS
BASIC WELDING JOINTS
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WELDING DRAWINGS
BASIC WELDING JOINTS
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WELDING DRAWINGS
BASIC WELDING JOINTS
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WELDING DRAWINGS
BASIC WELDING JOINTS
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The difference between Weld symbol Welding
symbol

• Weld symbol indicates the type of weld
• Welding symbol is a method of representing the
  weld on drawings. It includes supplementary
  information consists of the following 8
  elements.

• Reference line
• Arrow
• Basic weld symbol
• Dimension and other data
• Supplementary symbols
• Finish symbols
• Tail
• Specification, process or other reference

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18-2 Welding Symbols

• Tail of the symbol designates the welding
  specification, procedures, or other information
  used to make the weld
• Letters designate weld cutting processes (Table
  18-3)
• A-2, SAW, process specifications all can be found
  in the weld tail symbol

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Location significance of Arrow

• Arrow side- for fillet, groove, flanged weld
  symbols the arrow connecting the welding symbol
  reference line to one side of the joint
• Other side the side opposite the arrow side
• Both sides

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WELDING DRAWINGS
WELD TERMINOLOGY
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Weld terminology

• Leg
• Face
• Throat
• Groove radius
• Root opening (groove weld) is the space between
  the pieces before welding
• Root face
• Groove angle

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WELDING DRAWINGS
WELD TERMINOLOGY
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WELDING DRAWINGS
WELD TERMINOLOGY
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WELDING DRAWINGS
WELDING SYMBOLS
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WELDING DRAWINGS
WELD TERMINOLOGY
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WELDING DRAWINGS
WELD TERMINOLOGY
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WELDING DRAWINGS
SINGLE DOUBLE
FILLET
FILLET AND GROOVE WELDS
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WELDING DRAWINGS
WELDING DRAWINGS
SINGLE DOUBLE
SQUARE
FILLET AND GROOVE WELDS
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WELDING DRAWINGS
SINGLE DOUBLE
BEVEL GROOVE
FILLET AND GROOVE WELDS
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WELDING DRAWINGS
SINGLE DOUBLE
V-GROOVE
FILLET AND GROOVE WELDS
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WELDING DRAWINGS
SINGLE DOUBLE
J-GROOVE
FILLET AND GROOVE WELDS
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WELDING DRAWINGS
SINGLE DOUBLE
U-GROOVE
FILLET AND GROOVE WELDS
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WELDING DRAWINGS
SINGLE DOUBLE
FLARE- BEVEL GROOVE
FILLET AND GROOVE WELDS
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WELDING DRAWINGS
SINGLE DOUBLE
FLARE-V GROOVE
FILLET AND GROOVE WELDS
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Orientation of specific weld symbols

• Fillet, bevel-groove, J-groove, flare-groove,
  corner-flange welds symbols are drawn with the
  perpendicular leg always to the left
• Break in arrow-when only 1 member of a joint is
  to be prepared, the arrow has a break and points
  toward that member figure 18-9

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Location of weld symbol wrt joint

• Welds on the arrow side of the joint are shown by
  placing the weld symbol below the reference line
• Welds on the other side of the joint are shown by
  placing the weld symbol above the reference line
• Welds on both sides of the joint are shown by
  placing the weld symbol on both sides of the
  reference line

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Field welds All around welds

• All around welds

• Field welds

• Weld extending completely around a joint is
  indicated by a weld-all-around symbol placed at
  the intersection of the reference line and the
  arrow
• Figure 18-11
• Not required for welds extending around the
  circumference of a pipe

• Not made in the shop or at the place of initial
  construction
• Small black flag symbol is placed above and at
  right angles to the reference line
• Figure 18-10

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More about weld symbols.

• Combined weld symbols figure 18-12
• Contours obtained by welding
• Flat
• Convex
• Concave

• Finishing of welds
• grinding(G)
• Chipping(C)
• Machining (M)
• Rolling (R)
• Hammering (H)

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Last slide on weld symbols

• Multiple reference lines indicate a sequence of
  operations to be done at a single location

• Tail of welding symbol
• Welding process
• Tables 18-3,18-4
• Omitted when no references are required

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WELDING DRAWINGS
COMBINED WELDING SYMBOLS
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Design of welded joints

• The size of the weld should always be designed
  with reference to the size of the thinner member
• Fillets welds are cheaper and easier to apply
  than groove

• Full-strength fillet welds joining 2 different
  thicknesses of material should be sized using a
  table of recommended full strength weld sizes
  based on the thinner plate

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WELDING DRAWINGS
FINISHING OF WELDS
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18-3 Fillet Welds weld symbol (WS)

• Dimensions of fillet welds are shown on the same
  side of the reference line as the WS to the
  left
• Specify dimensions of fillet welds on both sides
  of a joint
• Vertical part of fillet weld symbol always on
  left

• If using a general note giving fillet weld
  dimensions, dimensions may be left off WS
• If dimensions differ from general note show them
  on WS
• Length of weld shown to right of WS

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More on fillet welds

• Staggered intermittent fillet welds are
  designated in the weld symbol by staggering where
  the weld symbol appears on the reference line
  (p.652)

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Size of fillet welds

• Table 8-5 p.651
• A practical method to size fillet welds is to
  design the weld for the thinner plate, making it
  sufficient to carry 1/3 to ½ the carrying
  capacity of the plate.

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WELDING DRAWINGS
COMPARISON OF A CAST SHAFT SUPPORT WITH A WELDED
STEEL SHAFT SUPPORT
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18-4 Groove Weld symbol

• Dimensions of groove weld are shown on the same
  side of the reference line as the welding symbol
• When both sides of a double-groove weld have the
  same (or different) dimension, both sides are
  dimensioned, however the root opening needs to
  appear only once
• When a general note governs dimensions of groove
  welds, groove welds need not be dimensioned on
  the weld symbol

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Back and Backing welds

• Back or backing weld symbols are used to indicate
  bead-type back or backing welds of singe-groove
  welds
• The back weld is made after the groove weld
• The backing weld is made before the groove weld

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WELDING DRAWINGS
APPLICATION OF BACK AND BACKING WELD SYMBOLS
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18-5 Other basic welds

• Plug
• Slot
• Spot
• Seam
• Surface
• Flanged
• Stud

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WELDING DRAWINGS
OTHER BASIC WELDING SYMBOLS AND THEIR LOCATION
SIGNIFICANCE