【作者】 张旭昀；

【导师】 王尊策；

【作者基本信息】 东北石油大学 ， 油气田地面工程， 2013， 博士

【摘要】 压裂技术是油气生产领域普遍应用的技术,其主要目的是人为增加油气流动的通道,提高油气层的渗透能力,从而增加油气产量。在压裂施工过程中,随着对压裂效率要求的提高,高压、大砂量压裂技术不断采用,使得管柱和井下工具的冲刷磨损越来越严重,甚至造成冲刷磨损失效,严重影响压裂生产的正常进行。为研究冲刷磨损机理,评价不同材料的腐蚀磨损性能,筛选抗冲刷磨损性能优良的材料,本文进行了不同材料的制备及系统的冲刷磨损实验研究。选用P110钢级的29CrMo44作为对比材料,经930-940℃淬火和610-620℃回火,组织为回火索氏体,晶粒度等级7.5-8级,屈服强度870MPa,抗拉强度921MPa,硬度21.5HRC,延伸率19.5%,力学性能优良。利用激光熔覆技术在P110钢基础上制备了含Cr量分别为20%、30%和40%的激光熔覆层(LCCs),熔覆层的稀释率分别为7%、5%、6%。沿熔覆涂层截面组织依次为平面晶、胞状晶和树枝晶,组织由马氏体和少量的残余奥氏体及铁素体组织,随Cr含量的增加,组织由柱状、树枝晶逐渐过渡到出现较多的碳化物,熔覆区主要物相为α(Fe,Ni),含铬量高时会出现Cr23C6、Cr7C3及其它形式的碳化物。熔覆层最高硬度513HV,平均硬度分别为350HV、376HV和462HV,明显高于P110钢。利用电磁感应炉熔技术,炼制了Fe-Cr-Mo-Mn-W-B-C-Si母合金,并用雾化装置制备非晶合金粉末,并使用XEM和XRD对粉术进行评价,表明粉末颗粒尺寸小于45μm,为完全非晶态结构。利用超音速热火焰喷涂技术,分别制备了厚度为200μm和400gm的非晶合金涂层(AMCs)。涂层化学成分分布均匀,孔隙率较小,分别为1.25%和1.45%。SEM下未观察到晶粒和晶界形态,TEM下发现存在少量晶体相,利用DSC法测定涂层中非晶相的含量,分别为74.9%和70.1%,证明涂层以非晶态结构为主。XRD分析显示,涂层中主要晶体相包括Fe2C、Cr7C3、Cr2B、M23C6和极少量的氧化物。显微维氏硬度测量表明涂层最高硬度可达900HV左右,平均硬度分别为828.3HV和713.2HV,涂层性能优良。以13Cr钢组分为基础,设计了铁基高铬合金的成分,并利用等离子熔炼装置制备了铁基高铬合金(FHCs)。用光谱仪测定了合金的化学成分,发现合金成分成分均匀,满足设计要求,属于超级13Cr系列。XEM形貌观察表明,合金组织由层片状马氏体构成,晶粒细小呈树枝状。XRD物相分析证实,合金的物相主要由马氏体相和Fe-Cr合金相组成。维氏测试结果显示合金的硬度达到296HV,高于普通0Cr13不锈钢。利用自制的冲刷磨损实验装置进行了冲刷磨损实验,对四种不同材料材料的冲刷磨损性能进行了总结评价,’冲刷磨损抗力由高到低分别为：非晶合金涂层>激光熔覆层>铁基高铬合金>P110钢。其中非晶合金涂层和激光熔覆层表现出较强的抗冲刷磨损性能,是比较理想的抗冲刷磨损材料。铁基高铬合金可以应用于强腐蚀环境并具有较强冲刷的工况中。四种材料的冲刷磨损机理不同,P110钢、低Cr激光熔覆层和铁基高Cr合金属于典型的塑性冲刷磨损,高Cr激光熔覆层属于脆性冲刷磨损,非晶涂层冲刷磨损规律与脆性材料类似,但冲刷磨损机理明显不同。更多还原

【Abstract】 Fracturing technology is commonly used in the field of oil and gas production, its main function is to increase the channels of oil and gas flow, the permeability of hydrocarbon reservoir will be enhanced and then the production of oil and gas will be promoted. In fracturing process, given the requirements of high fracturing efficiency, high pressure and sand content fracturing technology are used, the erosion wear of string and downhole tools become more and more serious, which may lead to erosion failure and severely affect the normal production of fracturing. To reveal the erosion wear mechanisms, different material was prepared and comprehensive experiments on erosion were conducted in this paper. The corrosion and wear properties of different materials were evaluated, and the material with excellent erosion resistance was found.The29CrMo44with P110grade was adopted as experimental materials, which were quenched at930-940℃and tempered at50℃, whose microstructures were tempered sorbite. The grain size of the materials are level5-8, yield strength870MPa, tensile strength921MPa, hardness21.5HRC, elongation19.5%, and mechanical properties are fine.The laser cladding coatings (LCCs) with the20%Cr,30%Cr and40%Cr were prepared on the P110substrate by laser cladding. The dilution ratios of the LCCs were7%,5%and6%, respectively. The microstructure of the cross-section were planar crystal, swelling crystal and dendrite crystal, and mainly of martensite with few retained austenite with ferrite. The cladding region were mainly for gamma a(Fe,Ni), and too much of Cr with the C element, gradually formed a Cr23C6, Cr7C3etc. The highest hardness of the LCCs (higher than P110) was513HV, and the average hardness were350HV,376HV and462HV, respectively.A Fe-Cr-Mo-Mn-W-B-C-Si master alloy was prepared by induction-melting of high-purity elemental constituents in a copper crucible. The powders were produced by high pressure argon gas atomization. The as-atomized powders were analysed by scanning electron microscope (SEM), transmission electron microscope (TEM) and X ray diffraction (XRD) phase, with the characteristics of completely amorphous and particle sizes in the range of less than45mm. The amorphous metallic coatings (AMCs) with the thickness of200and400μm were prepared by high-velocity oxy-fuel (HVOF) thermal spraying. The coatings present a typical layer structure of uniform chemical composition, which exhibited low porosity of1.25%and1.45%. There exist no evident grain boundaries in AMCs. The composite structure formation of some nanocrystallite phases embedded in the amorphous matrix by TEM. The major crystalline phases were composed of Fe2C, Cr7C3, M23C6, Cr2B, and some oxides by XRD. The micro-hardness of the AMCs were higher than900HV, which the average hardness were828.3HV and713.2HV, respectively.The Fe-based high chromium alloys(FHCs) were designed and prepared by plasma furna ce based on the composition of13Cr Steel. The accurate chemical composition of the prepare d alloys was tested by spectroscope, and the results show the contents are homogeneous whic h meet the design demands and the alloys are among super13Cr series. The SEM observation indicates that the main microstructures are lath martensite, and the grains are fine and branch ed. The phase is mainly composed of martensite and Fe-Cr phase which are proven by XRD. The Vickers hardness of the prepared alloys can reach296HV, which is higher than normal0Crl3.The erosion wear tests were conducted using a self-made jet apparatus for erosion wear. The erosive wear resistance of AMCs, LCCs, FHCs and P110decreased in the order as follows:AMCs>LCCs>FHCs>P110. The AMCs and LCCs exhibited highest erosive wear resistance, which were the optimal materials served in the erosive wear environments. FHCs were suitable for severe corrosive and abrasive environments. The erosive wear mechanism different from each other. The mechanism of the FHCs was brittle deformation, while those of P110, LCCs and FHCs were plastic deformation. The erosive wear behavior of AMCs similar to that of brittle materials, but with a different erosive wear mechanism.更多还原