【正文】
ve glide 既然切削過程中金屬變形的主要形式是剪切滑移,當然就可以用相對滑移(剪應變)來衡量切削過程的變形程度。當金屬沿滑移線發(fā)生剪切變形時,晶粒會伸長,如圖216所示。M類(相當于我國類)硬質合金是在、的基礎上再加入(或)而成。硬質合金的常溫硬度達,在800~1000℃時硬質合金還能進行切削,刀具壽命比高速鋼刀具高幾倍到幾十倍,可加工包括淬硬鋼在內的多種材料。高速鋼按切削性能可分為普通高速鋼和高性能高速鋼;按制造工藝方法可分為熔煉高速鋼和粉末冶金高速鋼。When the mean line of the tool holder is not perpendicular to the feed direction, the working cuttingedge angleκr and the minor cuttingedge angleκrˊ. will change () . MaterialsA cuttingtool must have certain characteristics in order to produce goodquality and economical parts.1. Certain characteristics that a cuttingtool must have(a)High hardness and wearresistance (b)Enough strength and toughness(c)High heat resistance(d)Good heat conductivity and thermal shock resistance(e)Good processability2. Cuttingtool materials most in use(a) Highspeed steels高速鋼是加入了較多的鎢()、鉬()、鉻()、釩()等合金元素的高合金工具鋼。粉末冶金高速鋼材質均勻,韌性好,硬度高,熱處理變形小,質量穩(wěn)定,刃磨性能好,刀具壽命較高。此類硬質合金不宜加工不銹鋼和鈦合金。教學內容提要時間分配備注TABLE 22 Designations, properties and application fields of CarbidesTypesDesignationsPhysical dynamic propertiesUsabilityApplication fieldsSuitable designations Hardness/HRABending strength/GPaWare resistanceImpact resistanceHeat resistanceMater