Popular brass is a copper-zinc binary alloy, and its zinc content has changed greatly, so its structure at room temperature is also very different. According to the binary state diagram of copper-zinc (Fig. 6), there are three types of brass at room temperature: brass with zinc content below 35%, brass with zinc content below 35%, brass with zinc content within 36%-46%, brass with zinc content within 36%-46%, brass with two phases (alpha+beta) at room temperature, brass with zinc content over 46%-50%. Copper, which consists of only beta phase at room temperature, is called beta brass.