Industrial Processes II INDUSTRIAL PROCESSES II INDUSTRIAL PROCESSES II INDEN 3313 INDEN 3313 Lecture 5 --Introduction to Lecture 5 --Introduction to Joining Processes, Welding Joining Processes, Welding Metallurgy, Combustion and Metallurgy, Combustion and Electrical Welding Processes Electrical Welding Processes
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Industrial Processes II INDUSTRIAL PROCESSES II INDEN 3313 Lecture 5 --Introduction to Joining Processes, Welding Metallurgy, Combustion and Electrical.
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Industrial Processes II
INDUSTRIAL PROCESSES IIINDUSTRIAL PROCESSES II
INDEN 3313INDEN 3313
Lecture 5 --Introduction to Lecture 5 --Introduction to Joining Processes, Welding Joining Processes, Welding
Metallurgy, Combustion and Metallurgy, Combustion and Electrical Welding Processes Electrical Welding Processes
Industrial Processes II
OVERVIEWOVERVIEW• Introduction to WeldingIntroduction to Welding
INTRODUCTION TO JOININGINTRODUCTION TO JOINING• DefinitionDefinition
– “Joining is an all-inclusive term, covering processes such as welding, brazing, soldering, adhesive bonding, and mechanical fastening”. [Kalpakjian, p. 855]
• Why Used?Why Used?– Difficult/Impossible to Manufacture as a Single
Piece– Easier/More Economical to Manufacture as
Components and then Assemble Either In-Plant, On-Site, or By Customer.
– (May) Allow Disassembly for Maintenance/Repair– Different Components Enable Different Properties
at Different Places on Assemble (e.g., Wear Surfaces)
Industrial Processes II
INTRODUCTION TO JOINING INTRODUCTION TO JOINING PROCESSESPROCESSES
• Welding (Definitions)Welding (Definitions)– Metal Joining Process in Which Coalescence is
Obtained Using Heat and/or Pressure• Coalescence - (From The Random House Dictionary)
– 1. to grow together or into one body 2. to unite so as to form one mass, community, etc.; blend; fuse; join; 3. to cause to unite into one body. from the Latin “alere” meaning to grow.
– A Metallurgical Bonding Accomplished by the Attracting Forces Between Atoms
– Joining Two (or More) Pieces of Material by Applying Heat, Pressure, or Both, With or Without Filler Metal to Produce Localized Union Through Fusion or Recrystallization Across the Interface.
Industrial Processes II
INTRODUCTION TO JOINING INTRODUCTION TO JOINING PROCESSESPROCESSES
• Welding - Key Elements in DefinitionsWelding - Key Elements in Definitions– “Pieces of Material” -- Same Material
Throughout– “Grow”, “Recrystallization” -- Grain Growth in
• Part/Weld Function and Operating Part/Weld Function and Operating Environment is DefinedEnvironment is Defined
• Type of Joint Selected/AnalyzedType of Joint Selected/Analyzed• Component Parts ManufacturedComponent Parts Manufactured• Surfaces to Be Welded Are CleanedSurfaces to Be Welded Are Cleaned• Components Are Aligned and Components Are Aligned and
Environment Formed Around Area to Environment Formed Around Area to Be WeldedBe Welded
Industrial Processes II
WELDING -- BASIC PROCESSWELDING -- BASIC PROCESS• Heat and/or Pressure Applied to Heat and/or Pressure Applied to
ComponentsComponents• Portion of Each Component MeltsPortion of Each Component Melts
– Temperature of Fusion Reached, Maintained
– Slag Produced
• (Optional) Add Molten (Filler) Material(Optional) Add Molten (Filler) Material• Heat From Process Affects Non-Melted Heat From Process Affects Non-Melted
Portion of ComponentsPortion of Components– Grain Structure Affected– Expansion, Warping– Out Gassing, Corrosion
Industrial Processes II
WELDING -- BASIC PROCESSWELDING -- BASIC PROCESS• Heat and/or Pressure RemovedHeat and/or Pressure Removed• Molten Material Begins to SolidifyMolten Material Begins to Solidify
– Coalescence/Grain Formation• Size, Shape, Strength Function of Cooling
Rate
– Dissolved Gases Evolve• Out Gassing,
– Shrinkage/Expansion of Weld Nugget Due to Change in State• Stresses, Shrinkage Voids
• Solidification Of Molten Material Solidification Of Molten Material CompleteComplete
Industrial Processes II
WELDING -- BASIC PROCESSWELDING -- BASIC PROCESS• Weld Nugget, Components Cool to Weld Nugget, Components Cool to
Environment WithdrawnEnvironment Withdrawn• Weld is CleanedWeld is Cleaned• Weld is Inspected/Tested/ApprovedWeld is Inspected/Tested/Approved• Paint or Other Coating AppliedPaint or Other Coating Applied• Assembly is UsedAssembly is Used
– Corrosion– Loading, Stress, Fatigue
Industrial Processes II
WELDING METALLURGYWELDING METALLURGY
• Melting/Fusion Process Similar to Melting/Fusion Process Similar to Casting and Heat TreatingCasting and Heat Treating
• Process ImpactProcess Impact– Temperature Applied/Reached– Heat Flux (BTU/Min)– Size of HAZ– Protective Environment Provided– Amount of Material Supplied– Cost Of Equipment– Operator Skill (Cost)– Position (Vertical,
– Causes• Trapped Gasses (Out-gassing from Metal or
Flux, Smooth Spherical H2 , O2 , N)
• Shrinkage Voids (Irregularly Shaped)• High Freeze Rate• Oil, Paint, Moisture, or Rust on Base Metal• Improper Arc Length or Current• Zinc Volatilization in Copper or Galvanized
• Rupture or Tear (Physical Discontinuity) in Weld Nugget
– Causes• Joint Too Rigid• Excessive Alloy Pickup from Base Metals• Defective Electrodes• Poor Fit (Variance in Nugget, Shrinkage)• Bead Too Small• High Sulfur in Base Metals