機(jī)械設(shè)計(jì)專(zhuān)業(yè)外文文獻(xiàn)翻譯-機(jī)械設(shè)計(jì)-全文預(yù)覽
【正文】 um, and vanadium, which improve the properties of steels, generally reduce machinability. The effect of boron is negligible. Gaseous elements such as hydrogen and nitrogen can have particularly detrimental effects on the properties of steel. Oxygen has been shown to have a strong effect on the aspect ratio of the manganese sulfide inclusions。 本科畢業(yè)設(shè)計(jì)（論文） 外文譯文 院 （系）： 機(jī)電工程學(xué)院 專(zhuān) 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 姓 名： 學(xué) 號(hào)： 指導(dǎo)教師評(píng)語(yǔ)： 簽名： 年 月 日 外語(yǔ)文獻(xiàn)翻譯 摘自 : 《制造工程與技術(shù)（機(jī)加工）》（英文版） 《 Manufacturing Engineering and Technology— Machining》 機(jī)械工業(yè)出版社 2021 年 3 月第 1 版 頁(yè)— 564560P 美 s. 卡爾帕基安 (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。 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 being entangled in the cutting zone. Because of the 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 socalled freemachining steels. Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (secondphase particles), which act as stress raisers in the primary shear zone. As a result, the chips produced break up easily and are small。 they require harder tool materials. Dimensional tolerance control may be a problem in machining aluminum, since it has a high thermal coefficient of expansion and a relatively low elastic modulus. Beryllium is similar to cast irons. Because it is more abrasive and toxic, though, it requires machining in a controlled environment. Cast gray irons are generally machinable but are. Free carbides in castings reduce their machinability and cause tool chipping or fracture, necessitating tools with high toughness. Nodular and malleable irons are machinable with hard tool materials. Cobaltbased alloys are abrasive and highly workhardening. They require sharp, abrasionresistant tool materials and low feeds and speeds. Wrought copper can be difficult to machine because of builtup edge formation, although cast copper alloys are easy to machine. Brasses are easy to machine, especially with the addition pf lead (leaded freemachining brass). Bronzes are more difficult to machine than brass. Magnesium is very easy to machine, with good surface fini
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