حياة طويلة

Criteria

Hot-dip galvanizing

Electro-galvanizing

Paint

Corrosion

Protection

Cathodic & barrier

Cathodic & barrier

Barrier

Coverage on corners/edges

Uniform coverage including corners, edges, and threads

Maybe thin or no coating in difficult to access areas

Holidays and pin holes possible, coating tends to thin on edges/corners

Coating thickness

1.7 to 3.4 mils

0.2 mils

1-3 mils

Bond strength

3,600 psi

300-600 psi

300-600 psi

Hardness

Alloy layer harder than base steel, with DPN hardness ranging from 179-250

50% as hard as base steel

Soft & susceptible to handling damage

Temperature range

-100 C to 200 C

-100 C to 200 C

Dependent on formulation

Paintability

Can be painted

Can be painted

n/a

Application

Shop

Shop

Shop or field

Conditions

Independent of weather

Independent of weather

Temperature & humidity restrictions

Procedure

After cleaning with series of chemicals, dipped in molten zinc bath, then spun to remove excess zinc

Clean steel, immerse parts in a zinc acid bath, and drive current through bath

Clean steel rinse, dry, brush or spray multiple coats

Performance:

Time to first maintenance

50+ years

10+ years

10-20 years

Suitability

Outdoor and indoor, applications

Outdoor sparingly, indoor main applications

Outdoor and indoor applications