Free-cutting brass

Japanese: 快削黄銅 - かいさくおうどう

…Alpha + beta brass, in which alpha and beta phases coexist, has similar properties, but although it is hard and strong, it requires heat processing. Furthermore, free-cutting brass, which has improved machinability due to the addition of lead (Pb), is widely used for applications in which cutting is required. There are also special brasses whose properties are improved by adding small amounts of additive elements. …

[Copper alloys]

…Alpha + beta brass has good hot workability, and is often used after being cut into extruded rods. Those containing lead are particularly good at cutting, so they are called free-cutting brasses, and their importance is increasing as automated cutting becomes more widespread. Brasses improved by adding 0.5 to 2% of additive elements to 7-3 brass or 4-6 brass are called special brasses. …

*Some of the terminology that refers to "free-cutting brass" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…α相とβ相が共存するα＋β黄銅も似た特性があるが，硬くて強度が大きいけれども熱加工の必要がある。さらに鉛Pbを添加して切削性をよくした快削黄銅は，切削加工して利用する用途に広く使われている。そのほか，少量の添加元素を加えて性質を改善した特殊黄銅もある。…