Free machinability

…The surface of a product that has been cut will also be more beautifully finished if it is machined under conditions where the cutting chips are cut into small pieces and fly away during cutting. The property of steel that creates such cutting conditions is called free-cutting property, and free-cutting steels are made by adjusting the components to enhance this property. Alloying elements added to increase machinability include manganese (Mn + sulfur) and lead (Pb), and the respective alloys are called sulfur free-cutting steel and lead free-cutting steel. …

*Some of the terminology that refers to "free machinability" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…また切削加工をうけた製品の表面も，切削中に切りくずが細かく切れて飛ぶ状況で加工されたほうが美しく仕上がる。このような切削状況をつくり出す鋼の性質を快削性といい，この性質を高めるために成分調整をして快削鋼がつくられている。快削性を上昇させるために添加される合金元素にはマンガンMn＋硫黄S，鉛Pbなどがあり，それぞれの合金は硫黄快削鋼，鉛快削鋼と呼ばれている。…

※「快削性」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報