【摘要】：本研究在自行設計和搭建的綜合實驗平臺上,進行了304不銹鋼的電脈沖輔助車削與聲電耦合(即超聲表面滾壓和電脈沖耦合)表面加工實驗。深入研究了電脈沖對304不銹鋼的切削加工性及超聲表面滾壓加工表面強化層性能的影響規(guī)律,并提出了相應的機制進行解釋。電脈沖輔助車削加工研究發(fā)現(xiàn):與普通車削相比,參數(shù)優(yōu)化的電脈沖可顯著降低304不銹鋼車削加工的主切削力和軸向表面粗糙度,減小加工硬化;切削區(qū)的塑性變形能力顯著增強,車削變質層流變厚度有所增加,切屑形成方式由原來的剪切塑性變形向剝離撕裂轉變;實驗所用的YG6X刀具前刀面的磨損形態(tài)從機械磨損向黏結磨損轉變,且黏結磨損隨電流密度增大而加劇;電脈沖過大會引起加工表面微弱氧化,表面粗糙度和顯微硬度上升,惡化加工表面質量;在本研究的實驗條件下,較理想的電脈沖參數(shù)為:均方根電流密度1.28A/mm2,峰值電流密度9.15A/mm2,脈沖頻率600Hz;研究引入量子力學的物質波理論和摩擦學的共振選擇摩擦能量逸散理論對電脈沖輔助車削加工的內在作用機理做出了探索解釋。聲電耦合表面加工研究發(fā)現(xiàn):與單純超聲表面滾壓加工相比,參數(shù)優(yōu)化的電脈沖可進一步顯著提高304不銹鋼超聲表面滾壓加工表面強化層的顯微硬度和表面光潔度,顯著促進表面微裂紋愈合;強化層表面的耐摩擦磨損性能得到進一步提高,獲得了更高的表面殘余壓應力,材料的抗拉強度增強;電脈沖導致304不銹鋼的層錯能升高,使得其塑性變形機理從以形變孿生為主轉變?yōu)橐晕诲e滑移為主;強化層中的形變孿晶數(shù)量大幅減少,同時馬氏體含量增加,晶粒更加細化;最終形成的表面強化層是少量較軟的奧氏體和大量較硬的馬氏體形成的軟硬鑲嵌結構;電脈沖過大會造成加工表面顯微硬度下降,殘余壓應力釋放,惡化表面加工質量,但同時會增加表面強化層的作用深度。在本研究的實驗條件下,較理想的電脈沖參數(shù)為:均方根電流密度1.03A/mm2,峰值電流密度7.66A/mm2,脈沖頻率600Hz。研究從電脈沖對位錯增殖和位錯運動的影響角度出發(fā),提出了電脈沖輔助塑性加工臨界電流密度的概念,對聲電耦合表面加工的內在作用機理做出了探索解釋。本研究工作對以304不銹鋼為代表的難加工金屬材料的高效切削和表面強化處理具有一定的指導意義!
[Abstract]:In this study, the surface processing experiments of 304 stainless steel were carried out on a comprehensive experimental platform designed and constructed by means of electropulse-assisted turning and acousto-electric coupling (i.e. ultrasonic surface rolling and electric pulse coupling). The influence of electric pulse on the machinability of 304 stainless steel and the properties of surface strengthening layer by ultrasonic surface rolling were studied, and the corresponding mechanism was put forward to explain the effect of electric pulse on the machinability of 304 stainless steel. It is found that compared with ordinary turning, the main cutting force and axial surface roughness of 304 stainless steel turning can be significantly reduced by the electrical pulse with optimized parameters, and the working hardening can be reduced. The plastic deformation ability of the cutting zone is obviously enhanced, the rheological thickness of the turning metamorphic layer is increased, and the forming mode of chip is changed from the original shear plastic deformation to the peel tear. The wear pattern of the front tool face of the YG6X tool used in the experiment changed from mechanical wear to bonding wear, and the bonding wear increased with the increase of current density, the surface of the machined surface was slightly oxidized and the surface roughness and microhardness increased due to excessive electrical pulse. Deterioration of machined surface quality; under the experimental conditions of this study, The ideal parameters of electric pulse are as follows: RMS current density 1.28A / mm2, peak current density 9.15A / mm2, pulse frequency 600Hz.Study on matter wave theory introduced quantum mechanics and resonance selective friction energy fugacity theory of tribology for electric pulse assisted turning The internal mechanism of processing is explored and explained. It is found that compared with pure ultrasonic surface rolling, the microhardness and surface finish of surface strengthening layer of 304 stainless steel can be further improved by optimized electric pulse, compared with pure ultrasonic surface rolling. The friction and wear resistance of the strengthened layer was further improved, and the surface residual compressive stress was increased, the tensile strength of the material was enhanced, and the stacking fault energy of 304 stainless steel was increased by electric pulse. The plastic deformation mechanism is changed from deformation twinning to dislocation slip, and the number of deformation twins in the strengthening layer is greatly reduced, and the martensite content is increased, and the grain size is more refined. The resulting surface strengthening layer is a soft and hard inlaid structure formed by a small amount of soft austenite and a large number of hard martensite. But at the same time, it will increase the action depth of the surface strengthening layer. Under the experimental conditions of this study, the ideal parameters are as follows: root mean square current density 1.03A / mm2, peak current density 7.66A / mm2, pulse frequency 600Hz. From the point of view of the effect of electric pulse on dislocation proliferation and dislocation movement, the concept of critical current density in electrically pulsed assisted plastic machining is proposed, and the internal mechanism of acoustoelectric coupling surface machining is explored and explained. This study has certain guiding significance for high efficiency cutting and surface strengthening treatment of refractory metal material represented by 304 stainless steel.
【學位授予單位】：清華大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TG51;TG661

【相似文獻】

相關期刊論文 前1條

1 方世杰;邵志芳;張存滿;;并網(wǎng)型風電耦合制氫系統(tǒng)經(jīng)濟性分析[J];能源技術經(jīng)濟;2012年03期

相關會議論文 前5條

1 鄭偉;程鈺間;樊勇;;一種可用于微波滅菌的電耦合同軸諧振腔[A];2011年全國微波毫米波會議論文集（下冊）[C];2011年

2 石霞;陸啟韶;;兩個電耦合Hindmarsh-Rose神經(jīng)元的完全同步[A];第七屆全國非線性動力學學術會議和第九屆全國非線性振動學術會議論文集[C];2004年

3 錢蓉;高慶;;Pb(Zr_(0.54)Ti_(0.46))O_3在力、電耦合作用下的性能變化[A];第三屆中國功能材料及其應用學術會議論文集[C];1998年

4 楊卓琴;張璇;;具有3個不同時間尺度的電耦合胰腺B細胞模型的組合簇放電[A];中國力學大會——2013論文摘要集[C];2013年

5 王海俠;陸啟韶;;對稱電耦合連接方式下的多尺度同步行為的轉遷過程[A];第十三屆全國非線性振動暨第十屆全國非線性動力學和運動穩(wěn)定性學術會議摘要集[C];2011年

相關重要報紙文章 前1條

1 廣西 付能材;Silicon Labs 推出基于CMOS工藝的數(shù)字解決方案[N];電子報;2013年

相關博士學位論文 前2條

1 王海波;304不銹鋼的電脈沖輔助車削與聲電耦合表面加工研究[D];清華大學;2016年

2 郭濤;中低溫地熱熱電耦合利用系統(tǒng)優(yōu)化研究[D];天津大學;2011年

相關碩士學位論文 前2條

1 戎青青;界面的力—電耦合和時間相關性研究[D];天津大學;2014年

2 廖浩明;熱電耦合軋制對鎂合金力學性能和顯微組織的影響[D];清華大學;2012年

，

本文編號：2238547