Case Hardening of Fasteners, Bolts & Screws

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At Nelson Heat Treating Co., Inc. we have developed innovative methods for heat treating fasteners, which is a very important aspect of their manufacture. The challenge is to achieve reliable and consistent results on small parts, which we often process in large volumes. Because of our expertise in providing quality work at very reasonable rates, there are almost always fasteners, bolts, or screws in production at our shop at any given time.

Since they are typically manufactured from mild steels, we utilize a case hardening process for fastener products because mild steels are not normally hardenable due to the low carbon content. Our case hardening process involves diffusing carbon, nitrogen, or boron into the outer layer of the steel in a high temperature environment. We then heat treat the now chemically-altered surface layer to achieve the desired hardness. The stability of our process allows us to maintain a uniform depth on all surfaces, including features such as delicate threads. The end result is a fastener with improved wear resistance and fatigue strength. In addition to improving the mechanical properties, we preserve the fasteners dimensional integrity, even on micro-sized parts with diameters as small as 0.0009”.

Case hardening is very compatible to mass production, but we can just as easily manage small lots weighing just a few pounds. We have specialized micro hardness testing equipment to verify the mechanical properties of small fastener parts. If you are interested in learning more about case hardening or any of our heat treating methodologies, please contact us today.