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在机械制造工业中,切削加工仍是一种主要工艺。随着机械工业的飞跃发展,越来越要求切削加工工艺进一步提高效率,提高零件加工精度和降低工具消耗。为此,作为重要途径之一,国外正在不断研究改善材料的可切削性,迅速发展易切削钢。近二十年来易切削钢发展很快,如日本1961年易切钢年产量仅为2万吨,1966年产量为14万吨,到1970年年产量剧增至44万吨。易切钢的种类繁多,如有添加S、Pb、Te、Se、Ca等元素的易切钢,还有Ca与AI组合的易切钢。近年来又提出了用Bi、As、Sn和N作为易切钢的成分。根据这些元素在钢中的不同作用可将它们大致分为两类:(1)S、Pb、Te、Se、Ca和Bi等元素以夹杂物形态存在于钢中而提高切削性能;(2)P、As、Sn、N及Cu～Al复合等元素溶于钢的基体而有微细的析出,提高了切削性能。作为汽车用钢,国外多采用Pb易切削钢和S易切削钢,为了制造重要用途的调质件和渗炭件,除要求易切钢具有优良的切削性能外,还需要有良好的综合性能。Ca易切钢基本能
In the machinery manufacturing industry, cutting is still a major process. With the rapid development of the machinery industry, more and more requirements of the cutting process to further improve efficiency, improve part machining accuracy and reduce tool consumption. To this end, as one of the important ways, foreign countries are constantly studying to improve the machinability of materials, the rapid development of free-cutting steel. In the past 20 years, the market for free-cutting steel has been developing rapidly. For example, in 1961, the annual output of free-cutting steel was only 20,000 tons in Japan, 140,000 tons in 1966 and 440,000 tons in 1970. Easy to cut a wide range of steel, such as the addition of S, Pb, Te, Se, Ca and other elements of free-cutting steel, Ca and AI combination of free-cutting steel. In recent years has also proposed the use of Bi, As, Sn and N as free cutting steel components. According to the different roles of these elements in steel, they can be roughly divided into two categories: (1) S, Pb, Te, Se, Ca and Bi and other elements exist in the steel as inclusions to improve the cutting performance; (2) P, As, Sn, N and Cu ~ Al composite elements dissolved in the steel matrix and fine precipitation, improved cutting performance. As automotive steel, the foreign use of Pb-free cutting steel and S free-cutting steel, in order to manufacture important use of conditioning parts and charring pieces, in addition to requiring easy cutting steel with excellent cutting performance, but also need a good overall performance . Ca free cutting steel basic energy