Corrosion Protection

There are several options for the protection of corrosion of springs.  There is usually a tradeoff between protection and cost. 

Method of Prevention

Cost

Protection

Results

Light oil covering or pack in VCI bags

Low

Short-term

 

Pre-plated wire

Low-mid

Medium-term

Provides reasonable corrosion protection, but cannot provide the salt spray hours of electroplate.

Pre-plated wire with a chromate dip

Mid

Medium to Long-term

Improve salt spray results without the problems of tangling in a barrel plate or introducing the chance of hydrogen embrittlement.

Post plating operation (ex. Zinc Plate)

Mid-high

Long-term

Zinc plating has better salt spray performance than pre-plate, but can have other problems, such as, tangling in a barrel plating operation and hydrogen embrittlement.

When electroplating spring wire (or cleaning in acid), the parts must be baked to drive off hydrogen immediately after plating. 

Oil tempered and Chrome Silicon wire should never be electroplated (or cleaned in acid) due to a high susceptibility to hydrogen embrittlement.  Mechanical Zinc plating may be an option on some springs. 

Stainless Steel

Mid-high

Long-term

Stainless Steel can be somewhat more costly on large springs, but may be a lower cost or better solution for small wire diameters, especially when considering some of the problems associated with plating. 

When considering stainless steel wire, we must keep in mind that stainless steel will require larger wire diameters than carbon steel material due to lower tensile and other mechanical properties.