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圆锥管螺纹连接在玻璃钢制品中应用非常普遍,许多制品的连接都离不开它。由于玻璃钢材料的特殊性,导致其螺纹加工质量难以保证,其中突出的问题是螺纹掉尖、掉扣、掉渣、表面烧蚀等,刀刃烧伤和磨损也比较严重,有时达到无法切削的程度。圆锥管螺纹加工是玻璃钢切削加工最难以掌握的工序之一。通过长期的切削加工实践,逐步地对玻璃钢圆锥管螺纹切削加工有了一些认识,初步掌握了玻璃钢圆锥管螺纹加工的一般规律。1 刀具的选择与加工方法 加工玻璃钢圆锥管螺纹的刀头材料一般采用YG8,正刃倾角λ0°-3°较为合适,两侧刃还应磨成大… 相似文献
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钢铁冶金用炭素材料(二)(续15) 总被引:1,自引:1,他引:0
钢铁冶金用炭素材料(二)(续15)刀具及其切削参数加工石墨电极时使用硬质合金(如牌号YG8)或高速钢(如牌号W18Cr4V)制成的车刀及铣刀进行切削。高速钢刀具坚韧性好、刃磨方便、价格较低,但红硬性稍差,只能耐500-600℃。硬质合金刀具具有良好的... 相似文献
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碳纤维增强复合材料(CFRP)是一种典型的难加工材料,文章利用化学气相沉积(CVD)金刚石涂层刀具以及Kistler 9129AA型测力仪,基于单因素实验法,探索了切削参数对CFRP加工过程中切削力、工件表面质量、刀具磨损的影响。实验结果显示:提高主轴转速可有效降低CFRP加工时的切削力,但随着切削深度和进给量的增加,切削力仍显著增加;CVD金刚石涂层刀具在切削42 m后,涂层出现剥落,主要原因是刀具表面与切屑产生磨粒磨损,并且刀具硬质合金基体与涂层热膨胀系数不同,在刀具温度升高的情况下使涂层出现裂纹,加快了涂层的剥落;如果想获得较好的表面质量和更少的加工缺陷,应该选用顺铣、大转速、小进给量及小切削深度。 相似文献
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利用三元烧结助剂MgO-Lu_2O_3-Re_2O_3(Re代表La、Gd、Er、Yb)对Si_3N_4陶瓷粉体进行热压烧结制成刀具,对一部分SN-Lu Yb样品再进行热处理,以使Si_3N_4陶瓷晶间玻璃相转变为结晶相。对以上所有样品进行断裂韧性、维氏硬度和XRD测试,然后在同工况下切削铸铁HT250。采用SEM和EDS分析切削后刀具的磨损表面形貌和元素成分。研究表明,利用三元烧结助剂MgO-Lu_2O_3-Re_2O_3烧结制备的Si_3N_4陶瓷样品完全满足切削刀具的使用要求,在切削铸铁HT250实验中,刀具磨损形式主要为磨粒磨损和粘结磨损,所有样品的切削寿命均超过了进口同型号Si_3N_4刀具,另外,经过热处理的SN-LuYb的切削寿命大幅提高了137%,说明晶间第二相对Si_3N_4陶瓷的抗磨损能力有决定性影响。 相似文献
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采用两种Si2N4刀具在普通车床上对CrWMn和45钢进行切削试验,并用SEM,EDAX,XPS等方法对刀具的磨损进行分析。结果指出:试验的陶瓷刀具材料在切削不同淬硬钢时均存在最佳切削速度。在FD01相比,FD02陶瓷刀具有更佳的切削性能,最佳切削速度可提高78%。在最佳速度以下切削,刀具侧面将发生粘着磨损;在最佳速度以上,则被加工材料产生微区熔化,导致材料大面积转移,发生剥层磨损,最佳速度以下切 相似文献
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An experimental study was carried out to determine the influence of rock properties on segment wear during the cutting of granite using an innovative diamond frame saw prototype. Wear is the main cost of frame saws with diamond-impregnated segments. Ten different granite types with a large market demand were cut by a stone-processing company. The diamond segment topography was studied. The microscopic appearance and a statistical analytical method were used to study the wear characteristics. The main diamond particle abrasion types are whole and micro-fractured crystals. No polished diamond particles resulted from using the frame saw prototype cutting stone. The frame saw cuts only in a half-cycle within a reciprocating stroke. The principal wear mechanisms of the diamond particles and the matrix are impact abrasion and flushing abrasive erosion, respectively. The statistical analysis indicated that uniaxial compressive strength, bending strength and quartz content were the first three rock properties that affected segment wear. The developed mathematical model can predict segment wear for manufacturers and users. 相似文献
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《Ceramics International》2019,45(13):16113-16120
Tool life and failure mechanisms of a microwave-sintered sub-crystal Al2O3/SiC ceramic tool (AS) in dry turning hardened steel were studied. The AS tool with plane face shows better cutting performance and wear resistance than the commercial ceramic tool SW500 and cemented carbide tool YG8 at both low and high cutting speeds. It's suitable for dry cutting at high speed (210–270 m/min), the cutting distance is 5–8 times longer than that of other two tools. The results indicate that the ceramic tool fabricated by this pressureless sintering technology can satisfy the requirements of high-speed machining. Wear forms of AS tool at low cutting speed are slight crater wear and groove wear, which were mainly caused by abrasion. At high cutting speed, tool failure forms are cater wear, groove wear and slight chipping caused by severe abrasion and adhesion. 相似文献
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WC–5TiC–10Co ultrafine cemented carbides were prepared and used for the cutting tool for AISI H13 hardened steel. The effect of cutting parameters on the tool life and tool wear mechanism was investigated, and conventional cemented carbide with the same composition and medium grain size were prepared for comparison. The results showed that WC–5TiC–10Co ultrafine cemented carbides possess higher hardness and transverse rupture strength, and showed better cutting performance than conventional insert with the same cutting condition. Tool life was analyzed by an extended Taylor's tool life equation, indicating that cutting speed played a profound effect on the tool life and wear behavior of both cutting inserts. SEM and EDS analysis revealed that there were major adhesive wear and minor abrasive wear on the rake of WC–5TiC–10Co ultrafine inserts, and increase of cutting speed resulted in a transition from abrasion predominant wear mechanism to adhesive wear on the flank face. As for the conventional inserts, there were combination of more serious abrasive and adhesive wear on the rake and flank. The favorable cutting performance of ultrafine WC–5TiC–10Co inserts was attributed to the higher hardness and less thermal softening during machining. 相似文献
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《Ceramics International》2020,46(12):20207-20214
Cutting performance and failure mechanisms of spark plasma sintered (SPS) ultrafine cemented carbides in dry turning Ti–6Al–4V were studied. The tools of UYG8 (WC-8wt%Co) and UYG8V2B10 (WC-8wt%Co-0.2 wt%VC-1.0 wt%cBN) exhibited higher lifetime and better processing quality than the commercial YG8 cemented carbide tool. The cutting distance of UYG-8 and UYG8V2B10 tools are 1.8 and 1.6 times longer than that of YG8, respectively. Cutting-edge breakage was found as the main failure forms of the SPS cemented carbide tools containing low Co content (≤6 wt%), whereas the SPS cemented carbide tools containing high Co content (≥8 wt%) exhibited flank and rake wear as main failure forms caused by abrasion, adhesion, diffusion, and oxidation. UYG8V2B10 tool wear mechanism was affected by cutting speed and depth. Wear mechanisms of UYG8V2B10 tool are mainly adhesive wear and oxidative wear at low cutting speed, but follow adhesive wear and diffusive wear at higher cutting speed. Moreover, with increasing cutting depth, tool failure forms are mainly breakage and chipping, largely induced by high cutting temperature and severe cutting vibration. 相似文献
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Yi Zhou Run-Ping Liu Zhen-Yong Lao Si-Chun Luo Yang You Shi-Kuan Sun Wei-Ming Guo Hua-Tay Lin 《Journal of the American Ceramic Society》2023,106(11):6987-6994
In this study, we investigated the cutting performance and wear mechanisms of Ti(C,N)-based cutting tools containing varying weight percentages (0%, 5%, 10%, and 15%) of high-entropy carbide (HEC) (V0.2Nb0.2 Mo0.2Ta0.2W0.2)C phase, when used for turning nodular cast iron. According to the turning test results, the cermet cutting tools containing 0 wt%, 5 wt%, 10 wt%, and 15 wt% HEC phases demonstrated effective cutting lives of 402, 720, 632, and 465 s, respectively. The tool with 5 wt% HEC phase showed the best cutting performance. When cutting nodular cast iron with cermet cutting tools, the main wear mechanisms observed were diffusion, oxidation, adhesion, and abrasion on the flank surface, along with diffusion, oxidation, and abrasion on the rake surface. The results of this study indicated that (V0.2Nb0.2Mo0.2Ta0.2W0.2)C could be adopted as an effective reinforced phase in the cermet cutting tools. 相似文献
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In this article, abrasion performance of commercial nylon 6 and nylon 6/montmorillonite (MMT) nanocomposites was studied. The polymer nanocomposites showed poor abrasion resistance compared to the neat polymer. The wear loss increased linearly with clay concentration. Changes in surface morphology, composition, and structure were investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR)‐attenuated total reflection spectroscopy, and X‐ray photoelectron spectroscopy (XPS). SEM images showed that all the abraded surfaces contained fractured particles. However, the abraded nanocomposite surfaces had much deeper grooves compared to the homopolymer. FTIR results showed an increase in the amount of α crystals and a decrease in the amount of γ crystals on all the surfaces after abrasion. This was attributed to the strain‐induced γ to α crystal transformation. The largest amount of α crystals was formed in the abraded surface of pure nylon 6, and the amount of α crystals formed decreased with increasing MMT content. XPS results showed an increase in the [Si]/[N] elemental ratio for all nanocomposites after abrasion, indicating an increase in the clay content of the surface. Abrasive wear mechanism is as follows: (1) tensile tearing is the dominant wear mechanism for all the samples; (2) the cutting mechanism becomes more important when MMT content increases; (3) the polymer matrix is easier to be removed than clay during the abrasion process; (4) in nylon 6/MMT systems, the poor abrasion resistance is attributed to defects at the clay‐polymer interface, resulting in greater wear of the polymer matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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《Ceramics International》2016,42(8):10037-10044
Cutter development has drawn a lot of attention for cast iron machining in recent years. In this study, a special cemented carbide of WC–5TiC–0.5VC–8Co (WTVC8) was used for a comprehensive HT250 gray cast iron machining test. Compared with the baseline plain WC–8Co(WC8) carbides, WTVC8 shows significantly higher tool life under the same cutting conditions due to significantly higher hardness and red hardness. The worn flank face observation shows that adhesion wear and oxidation are the main wear mechanisms and there is no apparent chipping/breakage and abrasion wear for both WTVC8 and WC8. Based on Taylor's equation, the accurate tool life models for both WTVC8 and WC8 have been constructed, which shows clearly that cutting speed has the most significant effect on tool life, followed by depth of cut and feed rate. The tool life models can serve as a quantified guidance for cutting performance optimization. 相似文献
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《Ceramics International》2017,43(12):8999-9004
In this work, CrAlN and TiAlN coatings were produced on silicon nitride cutting inserts via physical vapor deposition. The microstructure and hardness of the coatings, as well as the adhesive strength between the coating and the substrate were studied using a scanning electronic microscope, a micro hardness tester and a scratch tester, respectively. Continuous turning tests of the obtained CrAlN and TiAlN-coated silicon nitride cutting inserts were performed on gray cast iron to evaluate the cutting performances and the machining quality. The results show that the surface hardness of the Si3N4 cutting inserts could be improved by 87% and 50%, respectively, when applying the CrAlN and TiAlN coatings, thereby enhancing the abrasion resistance of the cutting inserts. At different tested cutting speeds, abrasive wear under compressional deformation and adhesive wear were identified as the main failure mechanisms for the two cutting inserts during continuous turning of gray cast iron. The machining quality of the gray cast iron workpieces machined using the uncoated, the CrAlN- or the TiAlN-coated inserts increased with the increment of the cutting speed. 相似文献
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《Ceramics International》2020,46(2):1621-1630
This work aims to reveal the cutting performance and wear mechanisms of Sialon ceramic tools for the high-speed face-milling of GH4099, with the goal of improving this process as well as designing more advanced ceramic cutting tools in the future. At the outset of this study, several single-factor experiments were designed with speed as a variable to gather various data on such tools. Failure patterns and tool life curves were first obtained through cutting tests. Afterwards, the tools were split at their place of wear (middle of notch and 1/2 depth of cut) to prepare for further analysis. Wear morphology and element composition distribution in the depth direction of the corresponding interface were then analyzed using a field emission scanning electron microscope (FE-SEM) and energy dispersive spectrometer (EDS) to explore potential diffusion and/or chemical wear. Finally, studies were conducted into the tools’ chemical wear under specific cutting conditions, finishing with a theoretical verification based on the thermodynamic principle of chemical reactions. This research discovered that notch wear was the main failure pattern for the high-speed face-milling of GH4099 under the suitable cutting conditions. Overall, the optimal cutting speed was 1000 m/min, with a tool life of about 3 min. Compared with cemented carbide tools, the machining efficiency for Sialon ceramic tools increased by over a factor of 16. The wear mechanisms for such tools demonstrated a mixture effect of abrasive, adhesive, diffusive and chemical wear. Diffusive wear mainly occurred in their flank faces, but did not constitute the main mechanism of notch wear; chemical wear proved to be a key reason for notch wear at higher temperatures. Based on the aforementioned research, this paper concludes with a proposed comprehensive model for notch wear. 相似文献
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遥传脉冲器转子在使用过程中存在磨损现象,这些磨损直接导致泥浆脉冲器无法实现随钻仪器采集的各种井下参数的上传。根据泥浆脉冲器转子本体磨损标准,分析泥浆脉冲器转子橡胶材质的性能、泥浆中岩屑摩擦以及外围部件缺陷所导致的泥浆脉冲器转子磨损。从设备管理过程中增加动平衡测试、改进橡胶性能、改进生产到应用过程中橡胶的存放等方法被提出,这些方法有助于降低磨损风险。研制了新型金属耐磨套替换方案,水循环和角度测试表明新型泥浆脉冲器转子性能明显改进。 相似文献