Brass.

"Brass" is an alloy with moderate strength and spreadability. The main components are copper and zinc.
It is used instead of gold to give a gloss similar to gold. And it is called "poor man's gold". As the proportion of zinc increases, the color decreases, and as the fraction decreases, it becomes reddish. As the rate of zinc increases, the hardness increases, but also the brittleness increases.
It is easy to cut due to its moderate hardness and extensibility that is not excessive and the price is moderate, so it is used frequently as a material for metal parts that require fine cutting. On the other hand, it tends to rust.


黄銅。真鍮。適度な強度、展延性を持つ合金。銅と亜鉛が主成分。
金に似た光沢を放つことから金の代用品にもされ、「貧者の金」と呼ばれる。亜鉛の割合が多くなるにつれて色が薄くなり、少なくなるにつれて赤みを帯びる。亜鉛の割合が増すごとに硬度を増すが、同時に脆さも増す。
適度な硬さと過度ではない展延性によって、切削加工が容易で、価格もほどほどなので、微細な切削加工を要求される金属部品の材料としての使用頻度が高い。加工しやすい反面、錆びやすい。