The combination of oxygen and moisture in a marine atmosphere increases rust-related costs for manufacturers, shippers and users of metal parts. This is why shipping metal parts overseas or exposing parts to a marine atmosphere requires careful, extensive planning if you want to ensure rust-free parts and equipment upon arrival.
What factors influence your rust inhibitor selection when facing a marine environment?
The Varieties Of Marine Corrosion
A marine environment presents many challenges, but two types of corrosion are possible when metals encounter a marine atmosphere:
- Galvanic Corrosion: Occurring between two or more different metals touching physically or through a conductive solution. Saltwater and polluted freshwater are extremely conductive with the potential for conductivity rising with the temperature.
- Crevice Corrosion: Occurring when water or moisture becomes trapped on a stainless steel surface. If oxygen is deprived to the surface of the steel, the oxide layer breaks down and the stainless steel rusts like any other unprotected metal.
The common takeaway from both kinds of marine rust outlined above – and any opportunity, for that matter – is to choose a rust inhibitor that absorbs in-air moisture while also doubling as packaging materials to prevent metals from touching during shipping.
How To Select The Right Rust Inhibitor For Marine Use
Below is a short list to help you choose a rust inhibitor for overseas shipments and marine environments:
- What is the type of metal that needs to be protected?
- What contaminants may potentially be left over on the metal before being packaged or what contaminants might the metal encounter before packaging?
- What is the length of protection required?
- Is easy application and removal a primary concern?
- What are the conditions of the manufacturing environment?
- What are the conditions of the receiving environment?
- What is the period of exposure?
- How many products need to be protected and what are their sizes?
How To Account For Exceptions To Rust Inhibitor Effectiveness
An inhibitor may be effective in one instance, but not effective in another. Other points that may impact the effectiveness of a rust inhibitor include:
- The chemical composition of the rust inhibitor and the corrosive medium
- The thermal stability of the inhibitor to continue protection through severe temperature and conditions
- The presence of other inhibitors and their influence on solubility
- The storage conditions of the parts at any stage: controlled, dry indoor, covered outdoor or unsheltered outdoor?
Sometimes the only true way to tell whether a chosen rust inhibitor will be effective is to replicate the conditions under which the parts and packaging will experience by sending a test shipment.
The benefits surely outweigh the potential rust-related costs of knowing for certain that the rust inhibitor you’ve chosen for marine use will provide the kind of protection you and your customers need.