viii Unit 12 | Structural Metals . . . . . . . . . . . . . 159 What Is Metal? 159 Metals Supplied for Welding 162 Metal Specifications 162 Unit 13 | Common Types of Joints and Welds. . . . . . . . . . . . . . . . . . . . . . . 165 Joint Types 165 Weld Types 165 Joints and Grooves 167 Terms Used to Describe Welds 167 Reading Welding Prints Unit 14 | Welding Symbols . . . . . . . . . . . . . 173 Elements of a Welding Symbol 173 Reference Line 175 Weld Symbol 175 Arrow 176 Tail 178 Supplementary Symbols 178 Dimensions 180 Contour and Finish Symbols 181 Notations 181 Nonpreferred Weld Symbols 181 Reading and Explaining a Welding Symbol 184 Unit 15 | Fillet Welds . . . . . . . . . . . . . . . . . . 193 General Use of Fillet Weld Symbol 193 Intermittent Fillet Welds 196 Fillet Welds in Holes and Slots 196 Specifying Fillet Weld Contours 196 Combination Weld Symbols 197 Unit 16 | Groove Welds . . . . . . . . . . . . . . . . 209 Root Opening, Groove Angle, and Bevel Angle 210 Preparation Size and Effective Throat of Groove Welds 210 General Use of Groove Weld Symbol 211 Groove Dimensions 212 Surface Finish and Contour of Groove Welds 213 Melt-Through, Back, and Backing Welds 213 Backing, Joint Spacers, and Runoff Weld Tabs 214 Flare-Groove Welds 215 Combination Weld Symbols 216 Unit 17 | Plug and Slot Welds. . . . . . . . . . . 227 General Use of the Plug and Slot Weld Symbol 227 Size of Plug Welds 228 Countersink Angle of Plug Weld 228 Slot Weld Details 230 Filling Depth of Plug or Slot Welds 230 Spacing Plug or Slot Welds 231 Surface Contour of Plug or Slot Welds 231 Unit 18 | Spot, Seam, and Projection Welds . . . . . . . . . . . . . . . . . 243 Spot Welds 244 Size and Strength of Spot Welds 244 Spacing of Spot Welds 244 Extent of Spot Welding and Number of Spot Welds 244 Flush Spot Weld Joints 245 Multiple Member Joint Spot Welds 246 Seam Welds 246 Size and Strength of Seam Welds 246 Length of Seam Welds 247 Dimensioning of Intermittent Seam Welds 247 Orientation of Seam Welds 248 Flush Seam Weld Joints 248 Multiple Joint Seam Welds 248 Projection Welds 248 Stud Welds 250 Side Significance 251 Stud Size, Spacing, and Number of Studs 251 Location of Stud Welds 251 Unit 19 | Surfacing Welds . . . . . . . . . . . . . . 261 General Use of Surfacing Weld Symbol 262 Surfacing Weld Dimensions 262 Location, Extent, and Orientation of Surfacing Welds 262 Unit 20 | Edge Welds . . . . . . . . . . . . . . . . . . 267 Multiple Member Edge Welds 267 Unit 21 | Pipe Welding. . . . . . . . . . . . . . . . . 273 Piping Drawings 276 Unit 22 | Brazed Joints . . . . . . . . . . . . . . . . 287 FM.indd viii FM.indd viii 8/13/2019 8:36:06 AM 8/13/2019 8:36:06 AM