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1、切削液（Cutting Fluids)游煌煌*1Cutting Fluids 游煌煌游煌煌 主要内容切削液的作用机理切削液的添加剂切削液的分类与选用切削液的使用方法Date2Cutting Fluids 游煌煌游煌煌 IntroduceThe medium in which the cutting process takes place is called the cutting fluid, it may consist of liquid or gas. However, solids may also be introduced into this fluid and they infl
2、uence the cutting process in their own way.Date3Cutting Fluids 游煌煌游煌煌 The reasons use of cutting fluidsImproving tool life; Reducing workpiece thermal deformation; Improving surface finish; Flushing away chips from the cutting zone. Date4Cutting Fluids 游煌煌游煌煌 Cutting fluids categoriesPractically all
3、 cutting fluids presently in use fall into one of four categories:lStraight oils lSoluble oils lSemisynthetic fluids lSynthetic fluids Date5Cutting Fluids 游煌煌游煌煌Straight oilsStraight oils are non-emulsifiable and are used in machining operations in an undiluted(未稀释) form. They are composed of a base
4、 mineral or petroleum oil and often contains polar lubricants such as fats, vegetable oils and esters as well as extreme pressure additives such as Chlorine, Sulphur and Phosphorus. Straight oils provide the best lubrication and the poorest cooling characteristics among cutting fluids. Date6Cutting
5、Fluids 游煌煌游煌煌 Synthetic FluidsSynthetic Fluids contain no petroleum or mineral oil base and instead are formulated from alkaline(碱性的) inorganic and organic compounds along with additives for corrosion inhibition. They are generally used in a diluted form (usual content ration = 3 to 10%). Synthetic
6、fluids often provide the best cooling performance among all cutting fluids. Date7Cutting Fluids 游煌煌游煌煌 Soluble Oil FluidsSoluble Oil Fluids form an emulsion when mixed with water. The concentrate consists of a base mineral oil and emulsifiers to help produce a stable emulsion. They are used in a dil
7、uted form (usual concentration = 3 to 10%) and provide good lubrication and heat transfer performance. They are widely used in industry and are the least expensive among all cutting fluids. Date8Cutting Fluids 游煌煌游煌煌 Semi-synthetic fluidsSemi-synthetic fluids are essentially combination of synthetic
8、 and soluble oil fluids and have characteristics common to both types. The cost and heat transfer performance of semi-synthetic fluids lie between those of synthetic and soluble oil fluids. Date9Cutting Fluids 游煌煌游煌煌Date10Cutting Fluids 游煌煌游煌煌 切削液的作用机理基本作用要求l冷却作用l润滑作用l清洗作用l防锈作用等还要求l无毒性、防霉性、稳定性、低污染性、
9、对设 备及管道涂漆的不侵蚀性、消泡性、不雾化 性、对皮肤及粘膜不刺激性等Date11Cutting Fluids 游煌煌游煌煌A cutting fluid is normally used for both cooling and lubrication. Different methods of aluminium machining demand different types of cutting fluid. Cutting fluids are under constant development, for instance for environmental reasons. F
10、or this reason it is advisable to keep abreast of new development. Date12Cutting Fluids 游煌煌游煌煌 Use of cutting fluids 1. Aqueous (水的) emulsion(乳状液) of mineral oil 2. Oil. Mineral, lard(猪油) or essential oil. 3. Compound oil containing mineral oil and lard or essential oil. 4. Aqueous chemical solution
11、s. 5. Paraffin (煤油) or alcohol. 6. Wax or a mixture of wax and grease (tallow). Date13Cutting Fluids 游煌煌游煌煌 一、冷却作用(cooling)功用l降低切削温度l 提高刀具耐用度和已加工表面质量l减少工件、刀具热膨胀l 提高加工精度l降低断续切削时温度差和热应力l 减少热裂Date14Cutting Fluids 游煌煌游煌煌 冷却作用（续一）冷却作用特别适用于l刀具材料的耐热性较低l工件材料的热膨胀系数较大l刀具材料及工件材料的导热性很低冷却性能取决于l导热系数、比热、汽化热、汽化速度、流
12、量 、流速等l一般：水乳化液油Date15Cutting Fluids 游煌煌游煌煌 冷却作用（续二）提高冷却作用措施l喷雾冷却法l液滴汽化而吸收大量热l降低切削液本身温度l油温冷却能力l油温粘度，流动性Date16Cutting Fluids 游煌煌游煌煌 二、润滑作用(lubricating)功用l降低摩擦系数The usual medium in which the cutting process takes place is air. It exerts an influence upon the course and results of the cutting process. T
13、his can be established experimentally by comparison with a cutting process taking place in a high vacuum.Date17Cutting Fluids 游煌煌游煌煌 润滑作用（续一）实验结果:l有空气切削比真空状态下切削，可使切削力减 小几倍原因l刚刚产生的刀屑间的摩擦表面是新鲜的。与空 气接触后立即氧化（几百分之一秒几十分之 一秒）形成氧化膜，使摩擦系数降低Date18Cutting Fluids 游煌煌游煌煌 润滑作用（续二）切削过程特点是非完全液体润滑摩擦l前刀面与切屑之间，压力在1GPa
14、，温度在 500，部分润滑膜破裂l由于切削液的渗透和吸附（毛细管）作用， 部分直接接触金属表面，对减少摩擦起一定 的作用这种摩擦润滑状态称为边界润滑摩擦Date19Cutting Fluids 游煌煌游煌煌 金属间边界润滑摩擦Date20Cutting Fluids 游煌煌游煌煌 润滑作用（续三）边界摩擦分为四种情况l低温低压边界润滑摩擦l 低速精切l高温边界润滑摩擦l 高速精切l高压边界润滑摩擦l 低速重切l高温高压边界润滑摩擦l 一般情况（又称极压润滑状态）Date21Cutting Fluids 游煌煌游煌煌 润滑作用（续四）造成高温高压（极压）边界润滑摩擦原因l一般切削液在工作200即
15、失去润滑能力l在切削加工的某些条件下，刀屑接触界面上 温度达6001000 ，压力可达1.5 2.0 GPa决定润滑性的因素l润滑膜强度l成膜能力（油性）l渗透能力l表面张力、粘度、亲合力Date22Cutting Fluids 游煌煌游煌煌 润滑作用（续五）流体润滑时，润滑膜的承载能力决定于粘 度(viscosity)l粘度承载能力边界润滑状态，因不存在完整的油膜，承 载能力与切削液的粘度无关，而与“油性” 有关l油性：指切削液中含有对金属 强烈吸附作用 的原子团，能在切屑、工件、刀具界面间形 成物理吸附膜（润滑膜）l润滑膜分为：物理吸附膜、化学吸附膜Date23Cutting Fluids 游煌煌游煌煌 润滑作用（续六）低速精加工时l在切削液中加油性添加剂（或直接加动、植 物油）高速切削或切难切削材料时l属于高温高压状态，须加入极压添加剂（如 硫化铁、氯化铁等）Date24Cutting Fluids 游煌煌游煌煌 三、清洗作用（washing)又称洗涤作用功用l切削时产生的碎屑和磨粉l粘附在工件、刀具和机床上，影响工件已加工表面 质量，降低刀具耐用度和机床精度lIn practice, cutting fluids exhibit good washing prop
