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Facts and Tips about Annealing Brass

May. 25, 2022

In this blog, we will present facts and tips on how to anneal brass. Chaochang is one of the most professional manufacturers specialized in induction heating equipment. With 20 years experience, our company has developed into a collection of research and development, production, marketing and technical service of high-tech modern induction heating machine manufacturer.

Understanding brass annealing

Occasionally you will see some ammunition that has significant discoloration around the neck and shoulders of the case. Essentially, the ends of the brass look like they have been burned or "scorched". The process that causes this is brass annealing.

The reality is that all new factory brass undergoes this treatment, but some manufacturers will polish their cases after the treatment to ensure that their brass looks shiny and new.

So, what is annealing, how does it affect brass and is it worth considering adding it to your reassembly process?

Facts and Tips about Annealing Brass

Connecting rod induction annealing equipment

Process Hardening

Like most metals, brass "work hardens" with repeated use - that is, as you repeatedly stretch and then resize (burnish, reload) brass, it becomes harder and more resistant to work over time. In the most extreme cases, this means that it may split in the chamber rather than expand, and at the more common end of the spectrum, it means inconsistent neck tension during reloading.

It's like a thin piece of steel - if you bend it back and forth enough times, the metal will eventually break. This is not ideal when we're talking about controlled explosions that happen near your face. Brass annealing is the process of "rejuvenating" brass, which results in longer brass life and improved consistency. It basically (and literally) takes the pressure off your brass.

Annealing Theory

Annealing is often confused with tempering. Both can be considered forms of heat treatment, but there is a risk of oversimplifying the issue - tempering brings metals to a lower temperature and tends to harden them, annealing is a shorter, hotter process and softens them.

We don't want to make the metal harder. Therefore, we are talking about high temperatures in the short term. Under-anneal and no real benefit will result, over-anneal and you may over-soften your brass. Something you don't really want when it means command, control and explosion.

Facts and Tips about Annealing Brass

Annealing Temperature

Online, the recommended temperatures that brass needs to reach vary slightly, from 600 to 800 degrees Fahrenheit (315 to 420 degrees Celsius for us in metric land). However, the average recommendation seems to lie in the 700 F range (370 C).

The color change seems to be one of the most common ways to identify the point where you go from the correct amount of annealing to over-annealing. If your brass is glowing, it is over annealed. Please throw it away, you may be making shooting dangerous.

Facts and Tips about Annealing Brass

Ribbed Rebar Induction Annealing Line

Annealing results

Long life

The main reason people anneal seems to be to increase the life span of their brass. More reloading and firing is required before the brass becomes difficult to resize easily and starts to form stress fractures and cracks. These are very, very bad. Therefore, the more you can revitalize brass and reduce stress, the longer it will last.


Consistency means repeatability, which is what you ultimately want in precision shooting; bullets that go to the same place over and over again. But having the brass "reset" to a uniform hardness means that the neck tension is the same every time you shoot, thus reducing another variable.

If I can set up a system that makes it easy to anneal brass, then that's what I plan to do every time I reload match brass.

Please contact us today if you want to know more details about annealing machines, and we also have induction hardening machine for sale.

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Baoding Chaochang Electromechanical Co., Ltd.