Heat treating is defined as the controlled heating and cooling of metals. From making the metals softer and easier to work with to improving their strength, we use heat treatment for a variety of different purposes. One of the main reasons we perform heat treating is to reduce steel fatigue life to ensure machinery lasts for as long as possible.
It’s important to note that there are several different heat treating methods that all yield different results in the metal. This post will cover a few of the different types of heat treating your steel may undergo.
Annealing
We anneal metals to relieve stress, soften the metal, increase ductility and improve grain structures. To anneal steel, we slowly heat the metal to the desired temperature, soak it and then let the piece cool slowly. During cooling, we either place the metal in an insulating material or turn off the furnace and let the piece cool inside the furnace.
After the steel has been annealed, it’s much easier to work with because it’s stronger and more ductile. There’s a much lower risk of the metal fracturing from bending or pressing while it’s being machined. Many steel tools are also annealed, so they will have a longer lifespan and be less likely to become damaged.
Normalizing
Metal failure often results from uncontrolled stress, which is where normalizing can help. Metals that have been normalized are much less likely to break and have a longer steel fatigue life because the pieces have no internal stresses.
The major difference between normalizing and annealing is that, with normalizing, the metal is air-cooled after it has been heated. Normalized steel is tougher than annealed steel. We’ll opt to normalize steel pieces instead of annealing them if the metal needs to withstand constant impact or be able to resist great external stresses.
Hardening
As the name suggests, the purpose of hardening is to make the steel harder, but it doesn’t just harden it—the process also makes steel stronger. Unlike annealing and normalizing, hardening requires the metal to be cooled rapidly after it’s heated in a process known as quenching. We’ll either cool the piece in water, oil or brine, depending on the type of metal we’re working with.
The downside of hardening is that the metal becomes more brittle and easier to break. To reduce the risk of the piece failing, we’ll often temper it after it’s been hardened and strengthened.
Tempering
To temper steel, we’ll heat the piece to a degree below its hardening temperature and then hold the piece at that temperature for a set amount of time. After the specified time has passed, we’ll let the piece air-dry.
One of tempering’s main heat treating benefits is that the piece remains as hard as needed but is not brittle enough to break when subjected to high amounts of stress.
Bring your steel to J.F. Heat Treating Inc.
Whether you need to prolong your steel’s lifespan or simply make it harder, bring your piece to J.F. Heat Treating Inc. We use industry-leading machinery to deliver the best results for your pieces. Call us today to get a quote or to learn more about the heat treating benefits.