随着机械工业的发展,机械加工设备的自动化和切削加工技术的不断提高,不仅大大地提高了切削加工的生产效率和产品质量,同时也促使易切削钢的用量和品种不断增长和发展。国内外易切削钢除了硫系、铅系易切削钢外,近十几年来又发展了钙系易切削钢。国外不少国家已将钙易切削钢大量用于生产,尤其是日本已普遍用于汽车、拖拉机等机械制造业中。 With the development of the machinery industry, the automation of the machining equipment and the continuous improvement of the cutting technology have not only greatly enhanced the production efficiency and product quality of the cutting process, but also promoted the continuous growth and development of the amount and varieties of free-cutting steel. In addition to domestic and foreign free-cutting steel, sulfur, lead-free cutting steel, the last decade and the development of calcium-based free-cutting steel. Many foreign countries have a large number of calcium free cutting steel for production, in particular, Japan has been widely used in automobiles, tractors and other machinery manufacturing industry.