三种表面改性处理技术对4145h钢性能的影响研究

发布时间：2018-04-18 18:13

本文选题：气相沉积 + 激光淬火　；参考：《西南石油大学》2016年硕士论文

【摘要】：石油作为一种战略物资在我国国民经济发展中具有举足轻重的作用,但是我国的石油资源十分短缺。为了保障国家能源安全,石油勘探开发难度不断增大,深井超深井、大斜度大位移井等复杂结构井的钻探数量成倍增长,钻具失效事故时有发生,严重影响了钻井安全和经济效益。本文在大量调研钻具失效分析及预防相关文献的基础上,结合钻井现场钻具失效的情况,对井下工具中的4145h钢进行了系统的材料性能研究;针对井下工具受力条件复杂,长期服役在交变应力、摩擦磨损、腐蚀环境等恶劣工况中,探索了三种表面改性处理技术对井下工具的材料性能的影响。本文进行了以下几个方面的研究:(1)通过大量调研三种表面改性处理技术相关文献,确定了 CVD气相沉积处理、激光淬火处理及QPQ盐浴复合热处理三种表面改性处理技术的工艺参数。选用4145h钢作为实验材料,按照国标HB5287-96《金属材料轴向加载疲劳试验方法》对标准材料进行试样的制取与加工。按照确定的三种处理工艺参数对原始试样分别进行表面改性处理。(2)对经过三种表面处理技术后的4145h钢进行了常温常压下的耐疲劳性研究。对不同表面改性处理的试样和原始试样进行旋转弯曲疲劳试验,在中短寿命区利用成组法进行实验数据的统计分析,在长寿命区采用配对升降法,得到了四种试样的S-N曲线;对实验结果进行分析,得到三种不同表面改性处理的试样与原始试样的疲劳S-N曲线的差异;利用扫描电子显微镜对疲劳试样的断口进行分析,研究了疲劳断裂的形成、扩展,得到不同工艺试样疲劳裂纹源区、扩展区和瞬断区的差异。(3)对经过三种表面处理技术后的4145h钢进行了常温常压下的耐磨性研究。四种试样分别进行耐磨性实验,得到了三种磨损量与时间的关系曲线,分析三种表面处理技术对试样的耐磨性的影响。实验发现,在短期磨损过程中CVD处理技术对试样耐磨性增强较大。利用显微硬度仪器对试样沿径向方向进行测试,得到硬度值与距表面深度的关系曲线。(4)对经过三种表面处理技术后的4145h钢进行了常温常压下的耐腐蚀性研究。四种试样分别进行饱和C02溶液腐蚀实验,通过公式计算得出在不同浸泡时间下四种试样的腐蚀速率。将三种表面处理试样与原始试样的腐蚀速率与时间关系曲线做对比,分析三种表面处理技术对材料的耐腐蚀性的影响。利用扫描电镜对试样断口和腐蚀表面形貌进行观察分析。
[Abstract]:As a strategic material, petroleum plays an important role in the development of our national economy, but the petroleum resources in our country are very short.In order to ensure the national energy security, the difficulty of petroleum exploration and development is becoming more and more difficult. The number of drilling wells with complex structures, such as deep wells, ultra-deep wells, large deviations and large displacement wells, has increased exponentially, and the failure of drilling tools has occurred from time to time.The drilling safety and economic benefits are seriously affected.In this paper, based on a large number of related literature on drilling tool failure analysis and prevention, the material properties of 4145h steel in downhole tools are systematically studied in combination with drilling site failure conditions, and the stress conditions of downhole tools are complex.The effects of three surface modification techniques on the material properties of downhole tools have been explored in the long service under adverse working conditions such as alternating stress, friction and wear, corrosion environment and so on.In this paper, the following aspects of the study: 1) through a large number of research on three kinds of surface modification technology related literature, determine the CVD vapor deposition treatment,The process parameters of laser quenching and QPQ salt-bath composite heat treatment.4145h steel was selected as the experimental material. According to the national standard HB5287-96 < method of axial loading fatigue test of metal materials, the standard materials were made and processed.The fatigue resistance of 4145h steel after three surface treatment techniques was studied under normal temperature and atmospheric pressure.The rotating bending fatigue tests were carried out on different surface modified samples and original samples. The S-N curves of four kinds of specimens were obtained in the long life region by the method of pairing up and down, and the statistical analysis of the experimental data was carried out by using the group method in the middle and short life region.By analyzing the experimental results, the differences of fatigue S-N curves between the three different surface modification samples and the original samples are obtained, and the fracture surface of the fatigue specimen is analyzed by scanning electron microscope (SEM), and the formation and propagation of fatigue fracture are studied.The wear resistance of 4145h steel after three surface treatment techniques was studied at room temperature and atmospheric pressure.The wear resistance of four kinds of specimens was tested, and the relationship curves between three kinds of wear amount and time were obtained, and the effects of three surface treatment techniques on the wear resistance of the samples were analyzed.It was found that the wear resistance of the samples was enhanced by CVD treatment during short-term wear.The corrosion resistance of 4145h steel after three surface treatment techniques was studied by means of microhardness test in radial direction, and the relationship curve between hardness value and depth from surface to surface was obtained. The corrosion resistance of 4145h steel was studied at room temperature and atmospheric pressure.The corrosion rates of the four samples were calculated by the formula under different immersion time.The relationship curves of corrosion rate and time between the three surface treatment samples and the original samples were compared and the effects of the three surface treatment techniques on the corrosion resistance of the materials were analyzed.The fracture and corrosion surface morphology of the specimens were observed and analyzed by scanning electron microscope (SEM).
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TE982;TG142.12

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