CFS Corrosion Resistance & Coatings 3

Question 1

Mechanical galvanizing differs from hot-dip galvanizing primarily because it:

Accepted Answer

Uses tumbling with zinc powder at room temperature instead of a molten bath

Answer

Mechanical galvanizing cold-welds zinc powder onto fasteners via tumbling with glass beads and does not involve a molten zinc bath, avoiding hydrogen embrittlement.

Question 2

What does ASTM F1941 govern regarding fastener coatings?

Accepted Answer

Electrodeposited coatings on threaded fasteners

Answer

ASTM F1941 specifies requirements for electrodeposited coatings on threaded fasteners including dimensional and performance requirements.

Question 3

Which environmental condition accelerates corrosion most significantly on bare carbon steel fasteners?

Accepted Answer

High humidity combined with chloride ions

Answer

The combination of high humidity and chloride ions is particularly aggressive, as chlorides break down passive films and water acts as the electrolyte for corrosion reactions.

Question 4

The minimum zinc coating weight for hot-dip galvanized structural bolts per ASTM A563 nut standards is closest to:

Accepted Answer

1.7 oz/ft²

Answer

ASTM A153 requires approximately 1.7 oz/ft² (Class C) for threaded fasteners in hot-dip galvanizing applications.

Question 5

Grade 5 fasteners electroplated with cadmium were historically popular in aerospace primarily because cadmium:

Accepted Answer

Provides excellent corrosion protection and is compatible with aluminum

Answer

Cadmium plating provides excellent corrosion resistance, low contact resistance, and is galvanically compatible with aluminum airframes, making it historically popular in aerospace.

(CFS) Certified Fastener Specialist Practice Test

(CFS) Certified Fastener Specialist Practice Test

CFS Corrosion Resistance & Coatings 3