Tempering Carbon Steel

There are a great many different types of metals out there and when you factor in all of the different alloys and compositions, you’re left with a vast gamut of options that all have different properties and applications. Perhaps the most common of all, however, is carbon steel, simply because of its numerous metallurgical properties and the profound number of applications it can have when it’s treated properly.

Now, because carbon steel is such a prolific presence in metallurgy, it begs for the attention that comes with each of the different ways it can be treated—specifically tempered. There are a variety of ways that carbon steel can be tempered, from normalized tempering to a quench temper in Gastonia, NC, and each of these presents a finished steel product that can be utilized across a wide variety of applications. Take a look at an overview of just a few different methods as to how carbon steel can be tempered:

  • Quench tempering: Water, various types of quench oils and even forced air can be used to quench temper in Gastonia, NC. The hardness of the steel will vary based on the rate of cool down and the composition of the alloy. Generally, in terms of quench tempering, carbon steel will not be heated higher than 401 degrees, as anything higher can result in brittleness after cool down, known as temper embrittlement.
  • Normalizing: Normalizing essentially refers to heating carbon steel to an appropriate temperature for the desired toughness or hardness, then allowing the alloy to cool down naturally, without any quenching. As a result, normalized steel is much stronger than quenched steel or even annealed steel.
  • Welding: Welding isn’t so much used as a way to temper steel itself, but to enhance the hardness of localized areas. Generally used when the size, shape or consistency of the alloy is to obtrusive to be heated entirely, welding can come in the form of arc welding, gas welding or even forge welding.

Interestingly enough, the properties vary so much between the different methods of tempering steel that when subjected to different temperatures, carbon steel will even change colors to reflect the unique properties that it’s being imbued with! Normalized steel tends to be a shiny grey, while quenched steel presents as a matte grey. As the temperature rises throughout the different methods of tempering the colors vary as so: faint yellow, straw yellow, light brown, brown, purple, dark blue, light blue and finally, grey-blue that represents the strongest temper.

Carbon steel can even be tempered with a process called differential tempering, in which different areas of the same piece of steel can be treated differently to preserve varying degrees of hardness. This type of differential tempering is mostly found in blades, to create a core that has a springy hardness, with edges that are tremendously stronger.

With all of the different tempering methods and outcomes associated with carbon steel, metallurgy is more than just a trial and error industry—it’s one based heavily on data, precision and understanding of the tools and materials being worked with.

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