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首頁> 外文學(xué)位 >Microstructural changes during simulated service of case carburized tapered roller bearings with different initial retained austenite profiles.
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Microstructural changes during simulated service of case carburized tapered roller bearings with different initial retained austenite profiles.

機(jī)譯：在模擬服務(wù)期間，具有不同初始保留奧氏體輪廓的滲碳圓錐滾子軸承的微觀結(jié)構(gòu)變化。

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摘要

The near surface layers of the inner races or cones of 6½ x 12 type tapered roller bearings manufactured 8720M steel were analyzed as a function of both initial retained austenite profile and simulated service mileage (rolling contact revolutions). This analysis examined the microstructural changes produced in these layers by examining the retained austenite content, residual stress, texture, diffracting particle size, microhardness, cone bore, and metallographic structure. A postproduction cryogenic thermal treatment was used to alter the retained austenite profile on selected cones.; The results of this research have shown that postproduction cryogenic thermal treatment results in a reduction of the as-produced retained austenite profile due to its transformation to martensite, a reduction in the surface compressive residual stress in the martensite, an increase in the surface tensile residual stress in the austenite, and an increase in cone bore diameter. In addition, the diffracting particle size of the austenite was also reduced.; Assessment of as-produced and cryogenically treated test cones as a function of simulated service mileage indicated that cryogenically treated cones experienced less transformation of retained austenite during rolling contact loading but developed compressive surface residual stresses of similar magnitude as the as-produced cones. Subsurface residual compressive stresses were significantly less in the cryogenically treated cones, but cone bore growth was reduced.
機(jī)譯：分析了由8720M鋼制成的6?x 12型圓錐滾子軸承的內(nèi)圈或圓錐的近表面層，作為初始?xì)堄鄪W氏體分布和模擬工作里程（滾動(dòng)接觸轉(zhuǎn)速）的函數(shù)。該分析通過檢查殘留奧氏體含量，殘余應(yīng)力，織構(gòu)，衍射粒度，顯微硬度，錐孔和金相組織來檢查這些層中產(chǎn)生的微觀結(jié)構(gòu)變化。生產(chǎn)后的低溫?zé)崽幚碛糜诟淖冞x定錐體上的殘留奧氏體輪廓。這項(xiàng)研究的結(jié)果表明，生產(chǎn)后的低溫?zé)崽幚碛捎谄湎蝰R氏體的轉(zhuǎn)變而降低了所產(chǎn)生的殘余奧氏體分布，減少了馬氏體中的表面壓縮殘余應(yīng)力，增加了表面拉伸殘余物。奧氏體中的應(yīng)力，以及錐孔直徑的增加。另外，奧氏體的衍射粒徑也減小。評(píng)估作為模擬服務(wù)里程的生產(chǎn)和經(jīng)過深冷處理的測試錐，表明經(jīng)過深冷處理的錐在滾動(dòng)接觸載荷下經(jīng)歷的殘余奧氏體轉(zhuǎn)化較少，但產(chǎn)生的壓縮表面殘余應(yīng)力的大小與所產(chǎn)生的錐相似。在深冷處理過的錐體中，地下殘余壓縮應(yīng)力明顯減小，但錐體孔的生長減少了。

著錄項(xiàng)

  • 作者

    Magner, Scott Howard.;

  • 作者單位

    The University of Nebraska - Lincoln.;

  • 授予單位 The University of Nebraska - Lincoln.;
  • 學(xué)科 Engineering Metallurgy.
  • 學(xué)位 Ph.D.
  • 年度 2001
  • 頁碼 183 p.
  • 總頁數(shù) 183
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 冶金工業(yè);
  • 關(guān)鍵詞

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