發(fā)布時間：2019-01-26 21:44

【摘要】：電解加工中,電流效率曲線不僅是計(jì)算加工間隙和電解加工速度的重要基礎(chǔ)數(shù)據(jù),還可以反映出電解加工中集中蝕除能力的大小。精確測定電解加工電流效率曲線對于分析與掌握電解加工成形規(guī)律、精確設(shè)計(jì)工具電極具有極為重要的意義。在恒定的加工電壓下,保持恒定的加工間隙從而獲得恒定的電流密度是精確獲得電流效率曲線的關(guān)鍵。為了精確測定電解加工電流效率曲線,本文對以下內(nèi)容開展相關(guān)研究:1)介紹電解液正向流動與側(cè)向流動恒間隙電解加工方案,并對這兩種方案實(shí)現(xiàn)恒定加工間隙的過程進(jìn)行數(shù)學(xué)分析。分別設(shè)計(jì)了恒間隙電解加工裝置,優(yōu)化了入口流量控制和陽極引電方式。開展了側(cè)向流動和正向流動恒間隙法電解加工試驗(yàn),結(jié)果表明:與側(cè)向流動相比,采用正向流動對于實(shí)現(xiàn)恒定的加工間隙具有更好的響應(yīng)能力,電流波動小,確定正向流動恒間隙方案用以測定電流效率曲線。2)針對開放式正向流動恒間隙法的流場不均勻問題,設(shè)計(jì)一種背壓式正向流動電解液流動方式。建立開放式正向流動和不同出口數(shù)量下的背壓式正向流動的流場模型,開展了有限元仿真分析研究,仿真結(jié)果表明:與開放式正向流動相比,背壓式正向流動的流場更加均勻。開展了開放式正向流動和背壓式正向流動恒間隙法脈沖電解加工對比試驗(yàn)研究,結(jié)果表明:采用背壓正流式電解液流動方式可以將加工電流波動量從23%減小到4%,表面質(zhì)量從Ra=1.237μm提高到Ra=0.608μm,驗(yàn)證有限元仿真分析的準(zhǔn)確性和電解液流動方式設(shè)計(jì)的合理性。3)研究了具有倒圓角結(jié)構(gòu)的陰極內(nèi)孔絕緣環(huán)對加工區(qū)域入口流場的影響問題,仿真與試驗(yàn)結(jié)果表明:相比較于無絕緣環(huán),采用入口倒圓角的絕緣環(huán)可以有效減少加工間隙內(nèi)電解液入口處流場的空化現(xiàn)象,提高加工區(qū)域流場的均勻性,改善加工區(qū)電解液入口處的工件表面質(zhì)量。4)介紹采用恒間隙裝置進(jìn)行電解加工電流效率曲線測定的試驗(yàn)方法。針對不銹鋼2Cr13和鎳基高溫合金GH4169,在20%NaNO3溶液中,開展直流和脈沖電流電解加工電流效率曲線測定與分析研究,并對脈沖占空比對電流效率曲線的影響展開了對比試驗(yàn)分析。結(jié)果表明:在20%NaNO3溶液中,直流電解加工不銹鋼2Cr13,電流效率曲線具有非線性,但是加工鎳基高溫合金GH4169,電流效率曲線不具有非線性,ηω值隨電流密度的變化波動較小;當(dāng)采用脈沖電流進(jìn)行電解加工時,這兩種材料的電流效率曲線均具有非線性,而且隨著占空比的減小,非線性特性得到強(qiáng)化。
[Abstract]:In ECM, the current efficiency curve is not only the important basic data for calculating machining clearance and ECM speed, but also reflects the magnitude of concentrated erosion ability in ECM. Accurate measurement of current efficiency curve of ECM is very important for analyzing and mastering the forming law of ECM and designing tool electrode accurately. At constant processing voltage, keeping constant machining gap and obtaining constant current density is the key to obtain accurate current efficiency curve. In order to accurately measure the current efficiency curve of ECM, the following research works are carried out in this paper: 1) the electrolytic solution with forward flow and lateral flow with constant gap is introduced. The process of realizing constant machining gap between these two schemes is analyzed mathematically. The constant gap ECM device is designed, and the inlet flow control and anode power generation are optimized. Experiments were carried out on the side flow and forward flow constant gap electrolysis machining. The results show that compared with the lateral flow, the forward flow has better response ability to realize the constant machining gap, and the current fluctuation is small. The forward flow constant gap scheme is determined to measure the current efficiency curve. 2) to solve the problem of non-uniform flow field in open forward flow constant gap method, a back pressure forward flow electrolyte flow mode is designed. The flow field model of the open forward flow and the back pressure forward flow is established. The finite element simulation analysis is carried out. The simulation results show that the flow field of the back pressure forward flow is more uniform than that of the open forward flow. A comparative study on open forward flow and back pressure forward flow constant gap pulse ECM is carried out. The results show that the flow of back pressure positive flow electrolyte can reduce the fluctuation of machining current from 23% to 4%. The surface quality is improved from Ra=1.237 渭 m to Ra=0.608 渭 m. The accuracy of finite element simulation analysis and the rationality of electrolyte flow design are verified. 3) the influence of cathode inner hole insulation ring with inverted circular structure on the flow field at the inlet of the machining area is studied. The simulation and experimental results show that compared with the non-insulated ring, the cavitation phenomenon at the electrolyte inlet of the machining gap can be effectively reduced and the uniformity of the flow field in the machining area can be improved by using the inlet reverse circular ring. Improving the surface quality of the workpiece at the inlet of electrolyte in the processing zone. 4) the test method of measuring the current efficiency curve of ECM with constant gap device is introduced. The measurement and analysis of current efficiency curves of DC and pulse current ECM were carried out in 20%NaNO3 solution for stainless steel 2Cr13 and nickel-base superalloy GH4169,. The effects of pulse duty cycle ratio on current efficiency curves were compared and analyzed. The results show that the current efficiency curve of 2Cr13 stainless steel prepared by DC electrolysis in 20%NaNO3 solution is nonlinear, but the current efficiency curve of GH4169, is not nonlinear, and 畏 蠅 value fluctuates little with the change of current density. When the pulse current is used in ECM, the current efficiency curves of both materials are nonlinear, and the nonlinear characteristics are strengthened with the decrease of duty cycle.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG662

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 程小元;黃明濤;張明岐;傅軍英;張志金;;精密電解加工在航空發(fā)動機(jī)整體結(jié)構(gòu)件制造中的應(yīng)用[J];航空制造技術(shù);2015年Z2期

2 干為民;張艷紅;王祥志;褚輝生;;電解磨削加工方法研究現(xiàn)狀[J];電加工與模具;2015年05期

3 蔣利民;鄧文波;應(yīng)俊龍;;鋁合金電解加工中的鈍化行為及其對加工過程的影響[J];電化學(xué);2014年01期

4 劉德營;傅秀清;康敏;董朝盼;;基于有限元法的球形數(shù)控電解加工工藝試驗(yàn)研究[J];中國機(jī)械工程;2013年06期

5 孫倫業(yè);徐正揚(yáng);朱荻;;葉盤通道徑向電解加工的流場設(shè)計(jì)及試驗(yàn)[J];華南理工大學(xué)學(xué)報(bào)(自然科學(xué)版);2013年03期

6 王賀賓;郭鐘寧;羅紅平;;微細(xì)電解加工技術(shù)研究現(xiàn)狀與展望[J];組合機(jī)床與自動化加工技術(shù);2011年04期

7 謝巖甫;劉壯;陳偉;;微細(xì)電解加工技術(shù)的概況與展望[J];電加工與模具;2010年06期

8 呂少力;;波義耳定律在液壓缸加載系統(tǒng)中的應(yīng)用[J];液壓與氣動;2010年11期

9 劉祥偉;;電解磨削復(fù)合加工工藝參數(shù)選擇[J];制造技術(shù)與機(jī)床;2010年06期

10 朱棟;朱荻;徐正揚(yáng);徐慶;;陰極調(diào)速法測定電解加工ηω-i曲線特性的試驗(yàn)研究及其應(yīng)用[J];航空學(xué)報(bào);2010年04期

相關(guān)博士學(xué)位論文 前2條

1 王維;群小孔電解加工的關(guān)鍵技術(shù)研究[D];南京航空航天大學(xué);2010年

2 徐正揚(yáng);發(fā)動機(jī)葉片精密電解加工關(guān)鍵技術(shù)研究[D];南京航空航天大學(xué);2008年

相關(guān)碩士學(xué)位論文 前2條

1 單曉慧;鈦合金電解磨削加工工藝研究[D];大連理工大學(xué);2015年

2 孫元普;電解磨削加工鈦合金基礎(chǔ)試驗(yàn)研究[D];大連理工大學(xué);2014年

，

本文編號：2415938