本文關(guān)鍵詞：基于走刀軌跡的316L不銹鋼立式銑削表面完整性研究　出處：《上海交通大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 立銑加工 走刀軌跡 表面完整性 AISI-316L不銹鋼 重疊率 有限元仿真

【摘要】：論文以自然科學(xué)基金“核主泵葉輪多軸數(shù)控加工工藝規(guī)劃及優(yōu)化方法研究(No.51175339)”為依托。作為核主泵的核心部件,葉輪需要在高溫、高壓、核輻射的惡劣環(huán)境下進(jìn)行長(zhǎng)時(shí)間安全可靠的工作,要求葉輪表面具有很好的機(jī)械物理性能和水力特性。根據(jù)葉輪的特殊工作環(huán)境,常采用AISI-316L不銹鋼作為葉輪加工材料,這種材料具有很好的耐酸性、耐磨性、韌性以及良好的焊接性能,尤其具有很強(qiáng)的抗腐蝕性能,但同時(shí)它的切削加工性能較差,屬于難加工金屬材料。因此,針對(duì)AISI-316L不銹鋼材料銑削加工表面完整性的研究,對(duì)于提高葉輪加工表面的機(jī)械物理性能、水力特性、減少應(yīng)力腐蝕裂紋、增加使用壽命等具有重要意義�；诖�,以探索AISI-316L不銹鋼材料平面立銑加工表面完整性作為研究目標(biāo),采用有限元仿真與試驗(yàn)分析相結(jié)合的研究方法。分析了銑削加工工藝中走刀軌跡、銑削參數(shù)以及相鄰刀具路徑之間重疊率對(duì)于工件加工表面完整性的影響,以表面殘余應(yīng)力、表面加工硬化、和表面粗糙度三個(gè)方面作為衡量指標(biāo)。首先,為了模擬不同走刀軌跡條件下的平面立銑加工過(guò)程,基于Abaqus軟件建立了AISI-316L不銹鋼材料的三維熱-力耦合立銑有限元模型,此模型同時(shí)考慮了切削力與切削熱的作用,模擬過(guò)程與實(shí)際銑削加工過(guò)程基本符合。研究得到了工件表面殘余應(yīng)力分布、沿深度方向殘余應(yīng)力分布、以及表面塑性應(yīng)變分布等結(jié)果。同時(shí),基于此模型,研究了主軸轉(zhuǎn)速、進(jìn)給速度、銑削深度三要素對(duì)加工表面殘余應(yīng)力和塑性應(yīng)變的影響。其次,通過(guò)數(shù)控加工中心對(duì)AISI-316L不銹鋼材料進(jìn)行平面立銑加工試驗(yàn),研究中對(duì)工件加工表面殘余應(yīng)力、顯微硬度、粗糙度以及三維表面輪廓等表面完整性指標(biāo)進(jìn)行了測(cè)量。論文對(duì)比了表面殘余應(yīng)力有限元預(yù)測(cè)結(jié)果和試驗(yàn)測(cè)量結(jié)果,模型預(yù)測(cè)誤差不超過(guò)27%,驗(yàn)證了所建立的三維熱-力耦合立銑有限元模型的有效性。論文同時(shí)分析了四種走刀軌跡以及銑削參數(shù)對(duì)表面加工硬化和表面粗糙度的影響,提出了改善加工表面完整性的走刀軌跡以及銑削參數(shù)優(yōu)化組合選取措施。銑削加工過(guò)程中,由于行間距小于刀具直徑,從而使得相鄰刀具路徑之間存在重疊區(qū)域,重疊區(qū)域會(huì)出現(xiàn)兩次甚至多次重復(fù)切削現(xiàn)象。論文針對(duì)這種重疊現(xiàn)象,考慮重疊率K和重疊方向兩種因素,研究了重疊現(xiàn)象對(duì)工件加工表面完整性的影響,為平面立式銑削中根據(jù)不同的刀具直徑選擇合適的行間距以及走刀軌跡提供參考。
[Abstract]:The thesis is based on the Natural Science Foundation "Research on the process Planning and Optimization method of Multi-axis NC Machining of the Impeller of Nuclear main pump No. No. 51175339)". As the core part of the nuclear main pump, the impeller needs to be at high temperature. Under the harsh environment of high pressure and nuclear radiation, it is required that the impeller surface have good mechanical, physical and hydraulic properties, according to the special working environment of the impeller. AISI-316L stainless steel is often used as impeller processing material. This material has good acid resistance, wear resistance, toughness and good welding performance, especially has very strong corrosion resistance. But at the same time, its cutting performance is poor, so it is difficult to process metal materials. Therefore, the surface integrity of milling AISI-316L stainless steel materials is studied. It is of great significance to improve the mechanical and physical properties of the impeller surface, hydraulic characteristics, reduce stress corrosion cracking, increase service life and so on. The goal of this study is to explore the surface integrity of AISI-316L stainless steel by planar end-milling. The influence of cutter path, milling parameters and overlap rate between adjacent tool paths on the surface integrity of workpiece was analyzed by means of finite element simulation and experimental analysis. The surface residual stress, surface work hardening, and surface roughness are taken as the measurement indexes. Firstly, in order to simulate the process of plane end-milling under different path path conditions. Based on Abaqus software, a three-dimensional thermo-mechanical coupled end-milling finite element model of AISI-316L stainless steel is established, which considers the effect of cutting force and cutting heat. The simulation process is basically consistent with the actual milling process. The residual stress distribution along the depth direction and plastic strain distribution on the surface of the workpiece are obtained. At the same time, based on this model. The effects of spindle speed, feed speed and milling depth on the residual stress and plastic strain of the machined surface are studied. The surface residual stress and microhardness of AISI-316L stainless steel were studied by means of plane end milling test in NC machining center. The roughness and 3D surface contours are measured. The prediction error of the model is less than 27%. The finite element prediction results of surface residual stress and the experimental results are compared in this paper. The effectiveness of the three-dimensional thermal-mechanical coupled end-milling finite element model is verified. The effects of four kinds of cutter paths and milling parameters on the surface work hardening and surface roughness are also analyzed. This paper puts forward some measures to improve the integrity of machining surface, such as the path path and the optimal selection of milling parameters. In the milling process, the line spacing is smaller than the diameter of the cutter. Therefore, there are overlapping regions between adjacent tool paths, which will occur two or more times repeated cutting. In this paper, the overlap rate K and overlap direction are considered. The influence of overlap phenomenon on machining surface integrity of workpiece is studied, which provides a reference for choosing appropriate row spacing and tool path according to different tool diameters in planar vertical milling.
【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG54

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