March 10, 2020
Primer On Electroplating For Compression Springs, Part 2
In part one of this two-part blog series, we went over some of the basics on electroplating during the compression spring manufacturing process. Done for both protective and aesthetic reasons alike, electroplating is often a valuable part of this process – but one where efficacy may also vary depending on the material being used.
At Custom Spring Manufacturing, we use a detailed spring manufacturing process to produce all our quality custom springs, from compression springs to conical springs, torsion springs, and many others. In today’s part two, we’ll go over one common issue that may arise with electroplating certain materials, plus how you can reduce these risks and some other important factors to be aware of.
Hydrogen Embrittlement Notes
The issue we’re referring to is known as hydrogen embrittlement, and understanding it involves grasping the role hydrogen plays in the electroplating process. Hydrogen is the smallest element out there, meaning it can fit into extremely small surface openings – and this can be a problem for certain materials.
Specifically, if the spring material is porous in any way, hydrogen elements can make their way into the surface and cause micro-cracks in the material as it’s removed from the electroplating bath. These cracks then expand when the spring is deflected, often leading to spring failure that’s known as hydrogen embrittlement.
Now, in some cases, heating the spring directly after electroplating it will boil off the hydrogen present, limiting the risk of hydrogen embrittlement. However, this is not always the case.
Our final two sections will dig into the two common spring material types, their porousness and whether hydrogen embrittlement is a risk if electroplating them.
Oil-tempered spring materials are those that are heated in a high-temperature oven, then dropped into oil before being sent into a second, lower-temperature oven. Generally speaking, oil-tempered materials have a porous finish, meaning they are susceptible to hydrogen embrittlement during electroplating.
This process was done anyway for many years, but the constant fail rate here was so noticeable that hydrogen embrittlement in oil-tempered springs is actually now characterized as a design flaw, not a manufacturing flaw. Generally, spring manufacturers warn customers about the risks of electroplating oil-tempered springs.
Cold-reduced materials, on the other hand, begin at a larger size before being pulled through cone-shaped dies, which elongate and reduce the wire size. This process is often done several times to achieve the desired size. This develops a sheen on the material, one that makes it far less porous and not at risk of hydrogen embrittlement.
For more on the electroplating process or hydrogen embrittlement risks to be aware of within the spring manufacturing world, or to learn about any of our custom spring manufacturing services, speak to the staff at Custom Spring Manufacturing today.