WorksheetsChapter 15 - Powder Metallurgy
Total questions: 11
Worksheet time: 8mins
The particle size that can pass through a screen is obtained by taking the reciprocal of the mesh count of the screen
true
false
For a given weight of metallic powders, the total surface area of the powders is increased by which of the following (two best answers)
larger particle size
smaller particle size
higher shape factor
smaller shape factor
As particle size increases, interparticle friction
decreases
increases
remains the same
Which of the following powder shapes would tend to have the lowest interparticle friction
acicular
cubic
flakey
spherical
rounded
Which of the following statements is correct in the context of metallic powders (three correct answers)
porosity + packing factor = 1.0
packing factor = 1/porosity
packing factor = 1.0 - porosity
packing factor = -porosity
packing factor = bulk density/true density
Repressing refers to a pressworking operation used to compress a sintered part in a closed die to achieve closer sizing and better surface finish
true
false
Impregnation refers to which of the following (two best answers)
Jack
filling the pores of the PM part with a molten metal
putting polymers into the pores of a PM part
soaking oil by capillary action into the pores of a PM part
something that should not happen in a factory
In cold isostatic pressing, the mold is most typically made of which one of the following
rubber
sheetmetal
textile
thermosetting polymer
tool steel
Which of the following processes combines pressing and sintering of the metal powders (three best answers)
hot isostatic pressing
hot pressing
metal injection molding
pressing and sintering
spark sintering
Which of the following design features would be difficult or impossible to achieve by conventional pressing and sintering (three best answers)
outside rounded corners
side holes
threaded holes
vertical stepped holes
vertical wall thickness of 1/8 inch (3 mm)
Which of the following most closely typifies the sintering temperatures in PM? where Tm = melting temperature of the metal
0.5 Tm
0.8 Tm
Tm
