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Flashcards in Fundamentals of Welding Deck (16)
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What are the advantages of welding?

Provides a permanent joint with welded component becoming a single entity

Welded joint can be stronger than parent material if filler material is used and has superior strength properties to those of parents

Most economical way to join components in terms of material usage and fabrication cost

Not restricted to factory environments


What are the disadvantages of welding

Expensive int terms of labor cost

Inherently dangerous

Does not allow for convenient dis-assembly

Can suffer from certain quality defects


What is meant by faying surface

Part surfaces in contact or close proximity that are to be joined


Define Fusion weld

Use heat to melt the base metals.

Sometimes a filler material is added to the molten pool to facilitate the process and provide bulk and strength to welded joint.


What is the fundamental difference between a fusion weld and a solid-state weld

Solid state welding is where pressure or pressure and heat is used for joining

Fusion-Weld is heat alone


What is autogenous weld

A fusion-welding operation in which no filler metal is added


Discuss relationship between machine welding and automatic welding

Machine Welding - equipment that performs the operation under the continuous supervision of an operator

Automatic welding - equipment performing operation without control by a human operator


Name the five weld joints

butt joint

corner joint

lap joint

tee joint

edge joint


Define a fillet weld

Used to fill in the edges of plates created by corner, lap, and tee joints

Creates a cross-sectional area similar to a right triangle.


define a groove weld

Requires edges of part be shaped into a groove

Filler metal is used to fill in the joint.


why is surfacing weld different from the other weld types

Not used to join parts, but rather to deposit filler metal onto surface of a base part in one or more weld beads


Why is it desirable to use energy sources for welding that have high heat densities

High density heat energy is supplied to the faying surfaces and the resulting temperatures are sufficient to cause localized melting of base metals. The heat density must be high enough to melt filler metal


What is unit melting energy in welding?

quantity of heat required to melt a unit volume of metal starting from room temperature


What factors on which melting energy depend on?

heat to raise temperature of the solid metal to its melting point

melting point of the metal

heat to transform the metal from solid to liquid phase at melting point


define and distinguish the two terms: heat transfer factor and melting factor in welding

heat transfer factor - Ratio of the actual heat received by the workpiece divided by the total heat generated at the source

Melting factor - proportion of heat received at the work surface that can be used for melting.


what is heat affected zone

Metal in the zone has experienced temperatures that are below its melting point, yet high enough to cause micro-structural changes in the solid metal