机械设计与制造毕业论文

1毕业设计机械加工表面质量的影响因素学生姓名：王仲果指导教师：专业名称：机械设计与制造所在院系：机电工程系2016年10月I目录摘要·······························································································1Abstract··························································································2第一章基本概念···············································································31.1机械加工··················································································31.2切削加工··················································································31.3磨削烧伤..·················································································31.4表面冷作硬化..·········································································31.5表面材料金相组织变化·····························································4第二章影响工件表面质量的因素····················································52.1加工过程对表面质量的影响······················································52.2影响工件表面物理机械性能的因素········································6第三章提高机械加工工件表面质量的措施·····································83.1刀具方面··················································································83.2工件材料方面···········································································83.3切削条件方面···········································································83.4加工方法方面···········································································8第四章机械加工表面质量对零件使用性能的影响························104.1表面质量对零件耐磨性的影响················································104.2表面质量对零件疲劳强度的影响·············································104.3表面质量对零件耐腐蚀性能的影响·········································10II4.4表面质量对零件间配合性质的影响··········································114.5表面质量对零件其他性能的影响·············································11第五章结论····················································································12致谢····························································································13参考文献··························································································14大连海洋大学专科毕业设计摘要1摘要部分的机械设备零件的破坏，总是从零件表面开始的。产品的性能，特别是它的可靠性和耐久度，在很大程度上取决于零件表面层的质量。研究机械加工表面质量，其目的就是为了掌握机械加工中各个工艺对加工表面质量影响的规律，以便利用这些规律来控制加工过程，最终达到改善产品质量、增强产品使用性能的目的。随着工业技术的飞速发展,机器的使用要求越来越高,一些重要零件在高压力、高速、高温等高要求条件下工作,表面层的任何缺陷,不仅直接影响零件的工作性能,而且还可能引起应力集中、应力腐蚀等现象,将进一步加速零件的失效,这一切都与加工表面质量有很大关系。因而表面质量问题越来越受到各方面的重视。一台机器在正常的使用过程中,由于其零件的工作性能逐渐变坏,以致不能继续使用,有时甚至会突然损坏。其原因除少数是因为设计不周而强度不够,或偶然事故引起了超负荷以外,大多数是由于磨损、受到外界介质的腐蚀或疲劳破坏。磨损、腐蚀和疲劳损坏都是发生在零件的表面,或是从零件表面开始的。因此,加工表面质量将直接影响到零件的工作性能,尤其是它的可靠性和寿命。本文对机械加工表面质量进行了分析，指出了影响机械加工表面质量的因素，并提出了提高机械加工表面质量的措施，对工程实践有一定的指导作用。而且,正确地理解零件表面质量内涵,分析机械加工过程中影响加工表面质量的各种工艺因素,通过改变这些因素从而改善工件表面质量，提高产品的使用性能及对未来机械行业的发展具有重要的意义。关键词表面质量，粗糙度，机械性能，切削参数大连海洋大学专科毕业设计Abstract2AbstractPartofthemachineryandequipmentpartsdamage,alwaysstartfromthepartsofthesurface.Productperformance,especiallythereliabilityanddurabilityofitsquality,toalargeextentdependsonthepartsurfacelayer.Studyonthesurfacequalityofmachining,thepurposeistograspthevariousmachiningprocessonthemachiningsurfacequalityofthelaw,inordertousetheserulestocontroltheprocess,ultimatelyimprovetheproductquality,increaseproductperformance.Withtherapiddevelopmentofindustrialtechnology,requiresthatthemachineisusedmoreandmorehigh,someimportantpartsinhighpressure,highspeed,hightemperature,highrequirements,anydefectsonthesurfacelayer,notonlydirectlyaffecttheperformanceofparts,butalsomaycausestressconcentration,stresscorrosion,willfurtheracceleratethepartsfailure,allthishasmuchtodowiththequalityofthemachinedsurface.Thusthesurfacequalityproblemsbecomemoreandmoreimportant.Amachineinnormalusageprocess,theworkingperformanceofthepartgraduallydeteriorated,sothatcannotcontinuetouse,andsometimeseventhesuddendamage.Thereasonisbecausethedesignisnotinafewweeksandthestrengthisnotenough,oraccidentcausedbyoverload,mostlyduetowear,corrosionordamagetheexternalmediumfatigue.Wear,corrosionandfatiguedamageoccursinpartsofthesurface,orfrompartsofthesurface.Therefore,themachinedsurfacequalitywilldirectlyaffecttheperformanceofparts,especiallyitsreliabilityandlifetime.Basedontheanalysisofthemachiningsurfacequality,pointedoutthefactorsinfluencingthesurfacequalityofmachining,andproposestoimprovethemachinedsurfacequalitymeasures,therearesomeguidanceforengineeringpractice.Moreover,thecorrectunderstandingofthecontentofthesurfacequalityofparts,varioustechnologicalfactorsaffectingsurfacequalityanalysisofmachiningprocess,bychangingthesefactorssoastoimprovethequalityoftheworkpiecesurface,improvetheperformanceofproductsandplaysanimportantroleinthefuturedevelopmentofmachineryindustry.Keywordsurfacequality,surfaceroughness,mechanicalproperties,cuttingparameters大连海洋大学专科毕业设计第一章基本概念3第一章基本概念1.1机械加工机械加工：广意的机械加工就是凡能用机械手段制造产品的过程；狭意的是用车床、铣床、钻床、磨床、冲压机、压铸机等专用机械设备制作零件的过程。1.2切削加工刀具几何形状的复映刀具相对于工件作进给运动时，在加工表面留下了切削层残留面积，其形状是刀具几何形状的复映。减小进给量、主偏角、副偏角以及增大刀尖圆弧半径，均可减小残留面积的高度。此外，适当增大刀具的前角以减小切削时的塑性变形程度，合理选择润滑液和提高刀具刃磨质量以减小切削时的塑性变形和抑制刀瘤、鳞刺的生成，也是减小表面粗糙度值的有效措施。工件材料的性质。加工塑性材料时，由刀具对金属的挤压产生了塑性变形，加之刀具迫使切屑与工件分离的撕裂作用，使表面粗糙度值加大。工件材料韧性愈好，金属的塑性变形愈大，加工表面就愈粗糙。加工脆性材料