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  本文選題：硬密封球閥　切入點：耐磨耐蝕性能　出處：《蘭州理工大學》2017年碩士論文

【摘要】：球閥作為截止閥的一種,除了應(yīng)用于一般的工業(yè)管道,在西氣東輸、煤制油工程、宇航工業(yè)上也發(fā)揮著重要的作用。目前硬密封球閥存在腐蝕、強磨損而造成使用壽命過短問題,因此延長球閥的使用壽命已成為當下的研究熱點。本文將WC基硬質(zhì)合金用于球閥的球體和閥座,并對其在實際工況下的使用做了初步探究。本文采用低壓燒結(jié)技術(shù)制備四種成分的WC基硬質(zhì)合金,并且合金中采用了Co基和Ni基兩種粘結(jié)劑。合金中WC的含量分別為84%,88%,90%和92%,對應(yīng)的Co基粘結(jié)相的含量分別為14%和10%,Ni基粘結(jié)相的含量分別為8%和6%。運用光學顯微鏡(OM)、掃描電鏡(SEM)、能譜(EDS)、X線衍射(XRD)等研究合金組織結(jié)構(gòu)和物相組成,利用顯微硬度計測量合金的硬度,萬能電子試驗機測定其抗彎強度,利用表面綜合性能測試儀測定合金的耐磨損性能,利用電化學工作站測定的耐腐蝕性能,對合金制成的球體和閥座進行了開關(guān)實驗測定其使用壽命,分析實驗結(jié)果,可以得出如下結(jié)論。(1)低壓燒結(jié)出組織純凈的納米級WC基硬質(zhì)合金,合金晶粒尺寸隨WC含量的上升而增大。合金的硬度隨著WC含量的增加而增大,抗彎強度則與WC的含量無關(guān)。(2)隨著WC的含量升高,合金的耐磨損性能加強。低載荷下,合金幾乎不發(fā)生磨損;中載荷下,合金的磨損機理是磨粒磨損;高載荷下,合金主要磨損機制為粘著磨損。(3)常溫條件下,WC-6Ni和WC-14Co滿足耐磨球閥的需求,因而投入生產(chǎn)并用于球閥的閥座和角閥內(nèi)部。低溫條件下,溫度從20℃降到-110℃,WC基硬質(zhì)合金的硬度有輕微上升,然而在-196℃時硬度大幅下降,因而合金不適用于超低溫下的工況。(4)在酸性介質(zhì)中合金的耐腐蝕性能為:WC-14CoWC-10CoWC-8NiWC-6Ni。在堿性介質(zhì)中合金的耐腐蝕性能為:WC-10CoWC-6NiWC-8NiWC-14Co。在中性介質(zhì)的耐腐蝕性能為:WC-14CoWC-10CoWC-6NiWC-8Ni。WC基硬質(zhì)合金的耐腐蝕性十分優(yōu)秀,在三種介質(zhì)中耐腐蝕性分別為:酸性介質(zhì)中性介質(zhì)堿性介質(zhì)。因而堿性環(huán)境中時可以重點考慮采用WC基硬質(zhì)合金制備的閥門。
[Abstract]:Valve as a shut-off valve, in addition to the application in industrial pipeline in general, in the west east gas pipeline, coal oil project, the aerospace industry has played an important role. At present, the hard seal ball valve corrosion, strong wear caused by short service life, thus prolonging the service life of the ball valve has become a hot research topic at the moment. The WC based hard alloy for ball valve and valve seat, and its use in actual conditions and made a preliminary inquiry. The preparation of WC based hard alloy four components by low pressure sintering technology, and the alloy with Co based and Ni based two kinds of binder content in the alloy WC. Were 84%, 88%, 90% and 92%, corresponding to the Co based bonded phase content were 14% and 10%, the Ni based bonded phase content is 8% and 6%. respectively by optical microscope (OM), scanning electron microscopy (SEM), energy spectrum (EDS), X-ray diffraction (XRD) of alloy organization The phase composition and structure, microhardness tester measuring the hardness of the alloy, electronic universal testing machine and its flexural strength, wear resistance determination of alloy by comprehensive performance tester surface was measured by electrochemical workstation, the corrosion resistance of alloy ball and seat to switch the experimental measurement of service life analysis the experimental results, we can draw the following conclusions. (1) low pressure sintering microstructures of pure nanometer WC based hard alloy, the alloy grain size increased with the increase of the content of WC. The hardness of the alloy increases with the increase of WC content, the bending strength has nothing to do with the content of WC. (2) with the increase of WC content and strengthen the wear resistance of the alloys. Under low load, there is almost no alloy wear; in load, the wear mechanism of the alloy is abrasive wear; under high load, the main wear mechanism is adhesive wear alloy. (3) at room temperature. Under WC-6Ni and WC-14Co meet the needs of the wear-resistant ball valve, put into production and for the valve seat and valve angle valve inside. Under the condition of low temperature, temperature from 20 degrees down to -110 DEG C, WC based cemented carbide hardness has increased slightly, but the hardness at -196 DEG C greatly decreased, thus not suitable for super alloy under low temperature conditions. (4) the corrosion resistance of the alloy in acidic medium, the corrosion resistance of WC-14CoWC-10CoWC-8NiWC-6Ni. alloy in alkaline medium: WC-10CoWC-6NiWC-8NiWC-14Co. in neutral medium corrosion resistance: WC-14CoWC-10CoWC-6NiWC-8Ni.WC hard alloy corrosion resistance is very good, in three kinds of medium corrosion resistance were: acid medium and neutral medium in alkaline medium. So it can be considered by WC based cemented carbide prepared by the valve in an alkaline environment.

【學位授予單位】：蘭州理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TH134;TG135.5

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本文編號：1661458