In many product areas, such as jewelry for instance, you may hear about a given material that’s “plated.” This term generally refers to finishes that are applied to a material to improve everything from its aesthetic qualities to its corrosion resistance.
At J & J Spring Enterprises, we’re happy to explain to you how the plating process is often involved in the spring manufacturing world – where it’s generally referred to as electroplating, a process often used for compression springs that are part of our selection of coil springs. Let’s go over some of the basics on this process and the factors involved.
In certain cases where springs will be visible for a given application, the electroplating process is used to improve their aesthetics so they give off a nice shine. In other cases, compression springs will be plated with finishes for rust prevention purposes – this prevents an oxidized environment from creating rust on the spring. Many springs are plated for this reason even if they will not be visible.
To complete the plating process, a spring is dropped in a bath that contains the required finishing elements. These elements may include zinc, silver or even gold. When the spring is immersed in the bath, a charge will be sent through it, lining up the ions in a way that the material adheres itself to the spring. This process creates hydrogen and leaves you with a plated spring.
Hydrogen is the smallest element, meaning that if the spring in question is porous even in minor ways, the hydrogen will risk micro-cracks in the material. These cracks can eventually lead to spring failure, which is known as hydrogen embrittlement.
To avoid this, the spring will be heated immediately after the electroplating process. This boils off the hydrogen before it can create any damage. This process is not 100% effective, but usually gets the job done.
Now, it’s important to note that not all spring materials are porous – meaning they won’t all be at risk of hydrogen embrittlement. Here are the two types of spring materials to consider here:
- Oil-tempered: These are heated in an oven, then immersed in oil before being heated in a second, lower-temperature oven. They have several alloys possible. Oil-tempered spring materials are porous, meaning they could be susceptible to hydrogen embrittlement without the right precautions taken.
- Cold-reduced: These materials begin at a larger size, then are pulled through cone-shaped dies to make the wire smaller and longer. This process is done several times to achieve the desired size. This develops a sheen on the surface of the material, one that makes it much less porous and less susceptible to hydrogen embrittlement.
For more on the electroplating process and materials involved, or to learn about any of our custom spring manufacturing services, speak to the staff at J & J Spring Enterprises today.