【摘要】：滲碳軸承鋼因其高承重和耐大沖擊性能的特點,能很好的滿足我國航空航天,冶金和高鐵等需求。為此,試驗鋼試圖通過獲得高潔凈度,細晶化和均勻化等良好的組織特點來滿足其成為構件時的使用要求。因此本論文首先對影響晶粒的鍛造工藝進行了熱變形行為的模擬研究,同時分析后續(xù)熱處理和滲碳等對晶粒的影響。其次對試驗鋼心部組織特點和強韌性能進行分析研究,也為獲得良好的滲層組織打下基礎。然后分析研究滲碳后滲層的組織特點和性能。最后進行旋轉彎曲疲勞及摩擦磨損性能試驗,分析心部和滲層的組織性能對疲勞和磨損性能的影響。試驗中主要采用金相顯微鏡(OM)、掃描電鏡(SEM)、透射電鏡(TEM)、X射線衍射(XRD)等測試手段。試驗鋼在應變量0.6、變形速率0.01 s-1、變形溫度1 000℃時發(fā)生了完全動態(tài)再結晶。將變形溫度控制在1 000~1 050℃之間可以得到均勻細小的晶粒組織。試驗鋼的心部可達到抗拉強度1 413 MPa和沖擊韌性162 J/cm2的良好強韌性,其原因是細小晶粒和板條馬氏體下的細晶強化和細小彌散的M3C和VC下的第二相強化。細小均勻的組織利于滲碳后得到良好的組織性能。滲層經(jīng)回火后組織主要為針狀馬氏體,少量殘余奧氏體和細小彌散的M3C與VC,晶粒仍保持在10~15μm,表層硬度可達到700 HV以上。在近表層時固溶強化起主要作用,隨著距離滲層表層越來越遠,第二相強化逐漸起主要作用。旋彎疲勞的斷裂機制由表層的沿晶斷裂轉變?yōu)檫^渡區(qū)的沿晶斷裂和韌性斷裂,中心區(qū)域為韌性斷裂。提高滲層表層硬度有利于提高旋轉彎曲疲勞性能。干摩擦滑動磨損的磨損機制以粘著磨損和氧化磨損為主,在脂潤滑條件下主要為疲勞磨損。脂潤滑與干摩擦相比,大大減小了摩擦系數(shù)和磨斑的尺寸。干摩擦微動磨損時,磨損機制均為粘著磨損和剝落。與載荷增大相比,頻率增大對磨斑直徑和剝落的產(chǎn)生影響較小。
[Abstract]:Carburized bearing steel can meet the requirements of aerospace, metallurgy and high iron due to its high bearing capacity and high impact resistance. Therefore, the test steel tries to meet the requirements of its use when it becomes a member by obtaining good microstructure characteristics such as high cleanliness, fine crystallization and homogenization. In this paper, the effect of heat treatment and Carburizing on the grain is analyzed. Secondly, the characteristics of the core microstructure and the strength and toughness of the test steel were analyzed and studied, which also laid the foundation for obtaining good infiltrating layer structure. Then the microstructure and properties of carburized layer were studied. Finally, the effects of the microstructure and properties of the core and infiltrating layer on the fatigue and wear properties were analyzed by means of rotating bending fatigue and friction and wear tests. (OM), scanning electron microscope (SEM), (SEM), transmission electron microscope (TEM), (TEM) X ray diffraction (XRD) and so on were used in the test. When the strain variable is 0.6, the deformation rate is 0.01 s ~ (-1) and the deformation temperature is 1 000 鈩，

本文編號：2178143