Brass is annealed by heating it above the temperature at which it recrystallizes, followed by cooling. Brass is softened as a result, and any internal stresses that the material had accumulated as a result of earlier procedures are released. Commonly, brass is annealed to soften bullet casings so they can be reused. The main concept is to heat the case’s neck and shoulder, but definitely not the body or base. The cartridge casings are heated with a blow torch until they glow a dull red, which is a typical and efficient technique. Then, the cartridges are submerged in water. The case should not be overheated since this will damage it. It’s better than nothing, even though the annealing results from this procedure might not be as uniform as those from other approaches.
Brass undergoes an annealing process, which involves applying heat, to change its physical and molecular characteristics and improve its machinability and workability. Brass is more prone to cracking under pressure as a result of cold working, which causes the material to harden and become more brittle. Brass is usable for subsequent processes like shaping, stamping, or forming after being annealed, which reorients the grain structure, restores its ductility. It entails annealing the workpiece at a high temperature, then chilling it to allow for the creation of fine grains. Brass may be annealed by either letting it cool at ambient temperature or quenching it in water, unlike steel, which requires controlled cooling of the object.
One great advantage of annealing brass is longevity. The main motivation for annealing brass seems to be to extend the life of the metal. Before the brass becomes too hard to resize easily and begins to develop stress fractures and cracks, more rounds must be fired and reloaded. These are awful, awful, awful. Hence, the brass will endure longer if you can revitalize it and reduce some of its stress. It’s said that you can’t anneal brass too many times because doing so just restores the qualities you desire in your brass, so long as you don’t overdo it. Depending on your method, or how tedious it is, you might want to think about doing it every three to four fires. But, many people with more automated setups just perform it as part of the brass preparation process each time they shoot.
A material’s mechanical qualities, such as ductility, strength, and malleability, are improved by annealing, which is one of its main benefits. An effective annealing process can increase a material’s capacity to tolerate stresses brought on by bending or twisting without breaking. As there is no risk of breakage or distortion, it is perfect for situations where parts must be handled often. Moreover, annealing can increase a material’s electrical conductivity and magnetic characteristics, making it perfect for magnetic or electronic components.
Only the neck and shoulder should be heated during annealing. These are the two areas, not the entire case, where we wish to be a little more flexible. This is why you frequently see videos and articles where guys use blowtorches to melt their brass while the case is submerged in water. The concept is that the water shields the bottom three-quarters of the brass from heat and annealing. Despite our efforts, some heat will still pass through the body as it moves downward.