6

CHAIN TERMINOLOGY

Grade of Chain:

 NACM (National Association of 

Chain Manufacturers) & ASTM (American Society 
for Test Materials) classify chains in various grades.  
The higher the grade, the higher the working load 
limit for the same size of chain. 
 
Working Load Limit (WLL):

 (Rated capacity) the 

maximum working load that should be applied in 
direct tension to an undamaged straight length of 
chain.  

Proof Test:

 (Manufacturing test force) the minimum 

tensile force that has been applied to a chain under 
a constantly increasing force in direct tension 
during the manufacturing process.  These loads are 
manufacturing integrity tests and shall not be used 
as criteria for service or design purposes. 

Minimum Breaking Force: 

the minimum force at 

which the chain during manufacture has been 
proven to break when a constantly increasing force 
is applied in direct tension.  Breaking force values 
are not guarantees that all chain segments will 
endure these loads. This test is a manufacturer’s 
attribute acceptance test and shall not be used as 
criteria for service and design purpose. 

Overhead Lifting:

 the process of lifting that would 

elevate a freely suspended load to such a position 
that dropping a load would present a possibility of 
bodily injury or property damage.

FINISHES

SC or Self-Colored:

  a chain lacking a coating or 

finish. 

EG or Electro-Galvanized (Bright Zinc/ Gold 
Chromate):

  a process that electrically deposits 

zinc to the surface of the chain. The zinc plate is 
very thin and is a cosmetic coating with very little 
corrosion protection. A clear/blue or yellow chrome 
is applied after the actual zinc coating to prevent the 
zinc plate from oxidizing. 

HDG or Hot-dipped Galvanized:

 a process that 

deposits a heavy layer of zinc onto the surface of 
chain. This coating helps protect against corrosion 
and the elements. Recommended for marine 
applications. 

Powder-Coated:

 an advanced method of applying a 

protective and decorative finish to a wide range of 
products used by industries and consumers.

Galv360

®

: 

a process based on a proprietary alloy 

of zinc, reacts with the steel at the molecular level. 
Instead of simply coating it, Galv360 alters the 
physical properties of the steel to create layers 
of intermetallic zinc/iron alloy, offering superior 
corrosion resistance and wear life.

TERMINOLOGY & FINISHES