Fundamentals of Welding Flashcards
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.
