本文選題：預(yù)氧化離子滲氮 + 離子滲氮+氧化��； 參考：《中國石油大學(華東)》2015年碩士論文

【摘要】：N80鋼是油田油管的主要用材,在使用過程中存在與采出液和抽油桿的腐蝕磨損問題。離子滲氮技術(shù)一直以來是解決N80鋼腐蝕磨損問題的常用方法,但離子滲氮主要存在的問題是滲氮速度慢、滲氮效果不佳。本文針對以上問題研究了在離子滲氮基礎(chǔ)上增加預(yù)氧化和后氧化的離子滲氮復(fù)合處理工藝,研究預(yù)氧化和后氧化工藝參數(shù)對滲氮層組織的影響,通過對滲氮層金相組織分析、XRD分析、SEM觀察、滲氮層顯微硬度、滲氮層厚度、耐腐蝕性分析以及耐磨性分析,得出了最佳的預(yù)氧化離子滲氮工藝和最佳的離子滲氮后氧化工藝。采用正交試驗方法研究預(yù)氧化工藝參數(shù)(預(yù)氧化溫度、預(yù)氧化保溫時間、氫氧比例和氣流量)對滲氮層效果的影響。研究結(jié)果表明,影響滲氮層性能的主次因素分別是預(yù)氧化溫度、氫氧比例、氣流量和預(yù)氧化時間;最佳預(yù)氧化工藝參數(shù)是預(yù)氧化溫度400℃,預(yù)氧化時間10min,氣流量200ml/min和氫氧比6:1。預(yù)氧化起到催滲作用且試樣滲氮層硬度和耐磨耐蝕性均得到提高。表面硬度最高達到了HV1270.2,滲氮層最厚達到了0.68mm,摩擦系數(shù)最小到0.498。經(jīng)過預(yù)氧化后試樣表面產(chǎn)生的Fe3O4和少量的Fe2O3氧化膜起到氮原子擴散通道的作用且氧化膜被還原后潔凈的表面提高了活性氮原子的被吸附幾率和吸附量,從而迅速向基體內(nèi)部擴散達到催滲的作用。采用正交試驗方法研究后氧化工藝參數(shù)(后氧化溫度、后氧化保溫時間和氫氧比例)對滲氮層效果的影響。由正交試驗結(jié)果得離子滲氮+氧化的最佳后氧化處理工藝參數(shù)為在350℃、保溫40min,氫氧比為6:1。后氧化處理提高了滲氮層的綜合性能。滲氮層厚度最高達到了0.69mm,摩擦系數(shù)最小為0.621,腐蝕電流最小到1.263uA。滲氮層由Fe3O4相,γ’-Fe4N相,ε-Fe2-3N相和α相組成,表面的氧化膜Fe3O4的摩擦系數(shù)較低并且化學穩(wěn)定性較高,因此試樣的耐磨耐蝕性均有不同程度提高,同時氧化膜的反應(yīng)生成過程氮原子繼續(xù)向內(nèi)部擴散使?jié)B氮層厚度硬度不斷提高。
[Abstract]:N80 steel is the main material used in oil field tubing. Ion nitriding technology has always been a common method to solve the problem of corrosion and wear of N80 steel, but the main problems of ion nitriding are slow nitriding speed and poor nitriding effect. In order to solve the above problems, the process of adding preoxidation and post-oxidation to the nitriding process was studied in this paper, and the effect of the process parameters of pre-oxidation and post-oxidation on the microstructure of nitriding layer was studied. By analyzing the microstructure of nitriding layer by XRD and SEM, the microhardness of nitriding layer, the thickness of nitriding layer, the corrosion resistance and wear resistance of nitriding layer, the optimum pre-oxidation ion nitriding process and the best post-ion nitriding process are obtained. The effects of pre-oxidation process parameters (pre-oxidation temperature, pre-oxidation time, hydrogen / oxygen ratio and gas flow rate) on the nitriding effect were studied by orthogonal test. The results show that the primary and secondary factors affecting the properties of nitriding layer are preoxidation temperature, hydrogen / oxygen ratio, gas flow rate and preoxidation time, and the optimum pre-oxidation process parameters are pre-oxidation temperature 400 鈩，

本文編號：2102510