本文選題：軸承 + 顯微組織��； 參考：《大連交通大學(xué)》2014年碩士論文

【摘要】：近年來,高速鐵路和城市軌道交通業(yè)高速發(fā)展,這些行業(yè)需要大量的使用各類軸承,對(duì)軸承的性能要求也隨之提高。然而對(duì)于軸承的許多關(guān)鍵零部件一般仍依賴進(jìn)口,所以很有必要開發(fā)自主知識(shí)產(chǎn)權(quán)的高性能軸承。本文首先選用企業(yè)常用的等溫淬火工藝制備了一套軸承,對(duì)自制的GCr15滾子和GCr18Mo內(nèi)外圈三個(gè)部件進(jìn)行了全面的檢測(cè),包括成分、硬度、組織、殘余應(yīng)力分布等,并分析該工藝對(duì)材料組織和性能的影響；然后在成品件的分析基礎(chǔ)上對(duì)使用的這兩種軸承鋼材料進(jìn)行了預(yù)備熱處理和最終熱處理,探討不同的熱處理工藝對(duì)材料組織和性能的影響,為提高城軌車輛用軸承的使用壽命提供重要的實(shí)驗(yàn)數(shù)據(jù)。研究發(fā)現(xiàn)：三個(gè)部件表面至心部組織及硬度均勻一致。軸承的滾子、內(nèi)圈、外圈的平均硬度分別為56.2HRC、59.9HRC和60.8HRC。軸承各部件主要組織由下貝氏體和碳化物組成,但內(nèi)外圈中的下貝氏體組織和碳化物都比滾子中的細(xì)小,滾子中下貝氏體針長(zhǎng)寬比約為7.5,內(nèi)外圈中下貝氏體針長(zhǎng)寬比約為10。滾子、內(nèi)圈和外圈碳化物的平均直徑分別約為0.55μm、0.39μm和0.42μm,其中直徑(0.2-0.8)μm碳化物所占比例分別約為86.5%、88.2%和93.2%。三部件碳化物占軸承組織的比例為一致,都約為10%。滾子、內(nèi)圈外表面均處于殘余壓應(yīng)力狀態(tài),表面的應(yīng)力狀態(tài)均是壓應(yīng)力且軸向壓應(yīng)力大于環(huán)向。滾子和內(nèi)圈熱處理后軸向和環(huán)向壓應(yīng)力平均值分別約為-480MPa和-90MPa,-588MPa和-390MPa；熱處理拋光后軸向和環(huán)向壓應(yīng)力平均值分別約為-398MPa和-61.5MPa,-483MPa和-231MPa。 GCr18Mo軸承鋼三周期球化退火后球化效果都比較理想,對(duì)最終熱處理后兩種軸承鋼組織及硬度的分析可以得出：兩試樣的組織均是由回火馬氏體+碳化物+殘余奧氏體組成,GCr15和GCr18Mo軸承鋼分別在840℃淬火160℃回火和860℃淬火180℃回火時(shí)的硬度值最高。
[Abstract]:In recent years, the high-speed railway and urban rail transit industry develop rapidly, these industries need to use a large number of bearings, the performance of the bearing requirements are also improved. However, many key parts of bearings are still imported, so it is necessary to develop high performance bearings with independent intellectual property rights. In this paper, a set of bearings was prepared by using the isothermal quenching process commonly used in enterprises. The three components of GCr15 roller and GCr18Mo inner and outer ring, including composition, hardness, microstructure, residual stress distribution and so on, were tested comprehensively. The effect of the process on the microstructure and properties of the bearing steel is analyzed, and then the two kinds of bearing steel materials used are treated with preparatory heat treatment and final heat treatment on the basis of the analysis of the finished parts. The effects of different heat treatment processes on the structure and properties of materials are discussed, which provide important experimental data for improving the service life of bearings for urban rail vehicles. The results show that the microstructure and hardness of the three parts are uniform and uniform. The average hardness of roller, inner ring and outer ring of bearing are 56.2 HRC 59.9HRC and 60.8 HRC respectively. The main structure of bearing components is composed of lower bainite and carbide, but the lower bainite structure and carbides in inner and outer ring are smaller than those in roller. The ratio of length to width of lower bainite needle in roller is about 7.5, and that of lower bainite needle in inner and outer ring is about 10. The average diameters of roller, inner ring and outer ring carbides are about 0.55 渭 m 0.39 渭 m and 0.42 渭 m respectively, in which 0.2-0.8) 渭 m carbides account for 86.5% and 93.2%, respectively. The proportion of three component carbides to the bearing structure is consistent, about 10%. The inner and outer surface of the roller are in the state of residual compressive stress, and the stress state of the surface is compressive stress and the axial compressive stress is larger than the circumferential stress. The average axial and toroidal compressive stresses of roller and inner ring after heat treatment are about -480 MPA and -90 MPA and -390 MPA respectively, and the average values of axial and circumferential compressive stresses after heat treatment are about -398 MPA and -61.5 MPA / 483 MPA and -231 MPA, respectively. The spheroidization effect of GCr18Mo bearing steel after three cycle spheroidizing annealing is ideal. By analyzing the microstructure and hardness of the two bearing steels after final heat treatment, it can be concluded that the microstructure of the two specimens is composed of tempered martensite carbide residual austenite and GCr18Mo bearing steel quenched at 840 鈩，

本文編號(hào)：1925717