Engineering Drawing and Design Chapter 18 Welding Drawings Seventh Edition Chapter 18 Welding Drawings

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)

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.

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

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

WELDING DRAWINGS BASIC WELDING JOINTS J-GROOVE FLARE BEVEL GROOVE SPOT PROJECTION SEAM FILLET PLUG SLOT SQUARE GROOVE BEVEL GROOVE APPLICABLE WELDS TYPE OF JOINT BASIC WELDING JOINTS

WELDING DRAWINGS BASIC WELDING JOINTS J-GROOVE FLARE V-GROOVE FLARE BEVEL GROOVE EDGE FLANGE SQUARE GROOVE V-GROOVE BEVEL GROOVE U-GROOVE APPLICABLE WELDS TYPE OF JOINT BASIC WELDING JOINTS

WELDING DRAWINGS BASIC WELDING JOINTS FLARE V-GROOVE FLARE BEVEL GROOVE EDGE FLANGE CORNER FLANGE SPOT PROJECTION SEAM FILLET SQUARE GROOVE V-GROOVE BEVEL GROOVE U-GROOVE J-GROOVE APPLICABLE WELDS TYPE OF JOINT BASIC WELDING JOINTS

WELDING DRAWINGS BASIC WELDING JOINTS J-GROOVE FLARE BEVEL GROOVE SPOT PROJECTION SEAM FILLET PLUG SLOT BEVEL GROOVE APPLICABLE WELDS TYPE OF JOINT BASIC WELDING JOINTS

WELDING DRAWINGS BASIC WELDING JOINTS EDGE FLANGE CORNER FLANGE SPOT PROJECTION SEAM EDGE PLUG SLOT SQUARE GROOVE BEVEL GROOVE V-GROOVE U-GROOVE J-GROOVE APPLICABLE WELDS TYPE OF JOINT BASIC WELDING JOINTS

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

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*

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

WELDING DRAWINGS WELD TERMINOLOGY

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

WELDING DRAWINGS WELD TERMINOLOGY

WELDING DRAWINGS WELD TERMINOLOGY

WELDING DRAWINGS WELDING SYMBOLS

WELDING DRAWINGS WELD TERMINOLOGY

WELDING DRAWINGS WELD TERMINOLOGY

WELDING DRAWINGS SINGLE DOUBLE FILLET FILLET AND GROOVE WELDS

WELDING DRAWINGS WELDING DRAWINGS SINGLE DOUBLE SQUARE FILLET AND GROOVE WELDS

WELDING DRAWINGS SINGLE DOUBLE BEVEL GROOVE FILLET AND GROOVE WELDS

WELDING DRAWINGS SINGLE DOUBLE V-GROOVE FILLET AND GROOVE WELDS

WELDING DRAWINGS SINGLE DOUBLE J-GROOVE FILLET AND GROOVE WELDS

WELDING DRAWINGS SINGLE DOUBLE U-GROOVE FILLET AND GROOVE WELDS

WELDING DRAWINGS SINGLE DOUBLE FLARE- BEVEL GROOVE FILLET AND GROOVE WELDS

WELDING DRAWINGS SINGLE DOUBLE FLARE-V GROOVE FILLET AND GROOVE WELDS

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

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

Field welds & All around 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

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)

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

WELDING DRAWINGS COMBINED WELDING SYMBOLS

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*

WELDING DRAWINGS FINISHING OF WELDS

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

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*)

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.

COMPARISON OF A CAST SHAFT SUPPORT WITH A WELDED STEEL SHAFT SUPPORT WELDING DRAWINGS COMPARISON OF A CAST SHAFT SUPPORT WITH A WELDED STEEL SHAFT SUPPORT

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

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

WELDING DRAWINGS APPLICATION OF BACK AND BACKING WELD SYMBOLS

18-5 Other basic welds Plug Slot Spot Seam Surface Flanged Stud

OTHER BASIC WELDING SYMBOLS AND THEIR LOCATION SIGNIFICANCE WELDING DRAWINGS OTHER BASIC WELDING SYMBOLS AND THEIR LOCATION SIGNIFICANCE