FUNDAMENTALS OF WELDING SME Video – Additional Processes Welding (vts_02) Welding Technology Weld Joints Physics of Welding Features of a Fusion Welded Joint In-class Assignment ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Basics of Arc Welding Joining Permanent joint Assembly Allow for disassembly ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Welding Joining process Heat and/or pressure Filler material Economical Accomplished “in the field” Disadvantages Labour cost High energy Difficult to detect quality defects Dangerous ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Fusion Welding – Heat Filler metal is added to the molten pool Autogenous weld - no filler metal is added Arc welding (AW) Resistance welding (RW) Oxyfuel gas welding (OFW) Manual arc welding operation ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Solid State Welding – Heat & Pressure Pressure alone or a combination Temperature is below melting point No filler metal is added Diffusion welding (DFW) Friction welding (FRW) Ultrasonic welding (USW) ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Principal Applications of Welding Construction - buildings and bridges Piping, pressure vessels and boilers Shipbuilding Aircraft and aerospace Automotive Railroad ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Welding on the Job Welder Second worker, called a fitter Welding fixtures and positioners Safety issues Ultraviolet radiation emitted in arc welding Viewing window filters out radiation Ventilation to exhaust fumes from fluxes ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Automation in Welding Hazards of manual welding Increase productivity Improve quality Machine welding Automatic welding Robotic welding ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

The Weld Joint Butt Corner Lap Tee Edge ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Fillet Welds (a) inside single fillet corner joint (b) outside single fillet corner joint (c) double fillet lap joint (d) double fillet tee joint Common for oxyfuel welding Requires minimum edge preparation ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Preparation increases cost Groove Welds (a) square groove weld, one side (b) single bevel groove weld (c) single V‑groove weld (d) single U‑groove weld (e) single J‑groove weld (f) double V‑groove weld for thicker sections Preparation increases cost ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Other Weld Types Plug weld Slot weld Spot weld Seam weld ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Other Weld Types Flange weld Surfacing weld ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Physics of Welding – Fusion (most common) Fusion for achieving coalescence High density heat energy Faying surfaces Temperatures cause localized melting Metal with minimum energy High heat densities Too low Too high W/mm2 (Btu/sec‑in2) ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Power Densities for Welding Processes W/mm2 (Btu/sec-in2) Oxyfuel 10 (6) Arc 50 (30) Resistance 1,000 (600) Laser beam 9,000 (5,000) Electron beam 10,000 (6,000) ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Power Density PD = power density, W/mm2 (Btu/sec‑in2) P = power entering surface, W (Btu/sec) A = surface area, mm2 (in2) ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Typical Fusion Welded Joint Principal zones in the joint Typical grain structure Heat affected zone HAZ Below melting point High enough to cause microstructural changes Heat treated region Failures often occur in HAZ ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

In-class Example A heat source can transfer 3500 J/sec to a metal part surface. The heated area is circular, and the heat intensity decreases as the radius increases, as follows: 70% of the heat is concentrated in a circular area that is 3.75 mm in diameter. Is the resulting power density enough to melt metal? ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

SME Video ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

In-class Assignment In a laser beam welding process, what is the quantity of heat per unit time (J/sec) that is transferred to the material if the heat is concentrated in circle with a diameter of 0.2 mm? Assume the power density provided in previous table. ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Additive Manufacturing ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

Time Permitting Content ©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e