文档介绍：本科毕业设计(论文)
外文译文
院(系): 机电工程学院
专业: 机械设计制造及其自动化
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摘自: 《制造工程与技术(机加工)》(英文版)
《Manufacturing Engineering and Technology—Machining》
机械工业出版社 2004年3月第1版
美 s. 卡尔帕基安(Serope kalpakjian)
施密德(Steven ) 著
原文:
MACHINABILITY
The machinability of a material usually defined in terms of four factors:
Surface finish and integrity of the machined part;
Tool life obtained;
Force and power requirements;
Chip control.
Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by ing entangled in the cutting zone.
Because of plex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below.
Machinability Of Steels
Because steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels.
Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (second-phase particles), which act as stress raisers in the primary shear zone. As a result, the chips produced break up easily and are small; this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers in resulfurized steels.
Phosphorus in steels has two major effects. It strengthens the f