Carbon steel fasteners are susceptible to environmental corrosion.
It is important to explore the options of anti-corrosion treatment to fasteners to protect them from corrosion-related failure, prolong the fasteners usage and to make your purchase worth its value.
Here are the 3 most common types of anti-corrosion treatment for carbon steel fasteners:
1) Electroplating
A process in which electric current is used to deposit metal, in this case zinc onto a workpiece.
The fastener is the cathode of the circuit and Zinc the anode. This is followed by submerging into an electrolyte solution that conducts the flow of electric current. The anode oxides the metal atom which dissolves into the solution. The solution with the metal atom solution then deposited to the cathode which forms the plated surface.
The process
The fastener is the cathode of the circuit and Zinc the anode. This is followed by submerging into an electrolyte solution that conducts the flow of electric current. The anode oxides the metal atom which dissolves into the solution. The solution with the metal atom solution then deposited to the cathode which forms the plated surface.
2) Mechanical Plating
Also known as sherardizing, the process of forming zinc-iron alloy on the surface of steel or iron.
The process
Tumbling of the products in the drum with Zinc, proprietary chemicals and glass beads. Followed by peening of the zinc powder onto the surface of the fasteners during tumbling process.
The size selection of the glass beads plays a crucial factor in affecting the outcome of the surface finishes. Areas with complex design such as edge, corner and thread may observe inconsistent coating thickness.
3) Dip-Spin Coating
The process of dipping followed by spinning of proprietary Zinc rich water-based coating.
The process
By dipping the product, here the fasteners into a zinc rich coating solution followed by centrifuged the excess coating off.
The temperature, viscosity, immersion time and spinning speed and direction are the controlled variables that allows users to customize the process recipe thus produce highly precise, measurable and repeatable results.
Comparison
Now can you tell the difference between these 2 types of surface treatment?
Hint: They are not the same
Reference:
1) Dip-Spin Coating. Retrieved from https://coatingsystems.com/dip-spin-coating/
2) (1997, December 1). Blog post. Why Use Dip/Spin Coating Technology. Retrieve from https://www.pfonline.com/articles/why-use-dip-spin-coating-technology
3) Paul C. Wynn, Business Manager, McGean-Rocho (UK) Ltd.(2001, January 1). Blog post. Mechanical Plating. Retrieve from https://www.pfonline.com/articles/mechanical-plating(1)
4) (2019, September 27). Blog post. 5 Corrosion Resistant Treatment Fasteners. Retrieve from https://monroeengineering.com/blog/5-corrosion-resistant-treatments-fasteners/
5) Mechanical Plating. Retrived from https://galvanizeit.org/corrosion/corrosion-protection/zinc-coatings/mechanical-plating
6) Mechanical Plating vs. Electroplating. Retrieved from https://www.ciprocessing.com/metal-finishing/mechanical-plating/mechanical-vs-electroplating.html