Steels which are utilized in the manufacturing of specific parts of military technology such as crankshafts of engines in heavy-duty vehicles or barrels of guns must be subsequently modified by heat treatment according to the requirements of customers. Despite the hard surface of martensitic structure obtained by hardening process, steels have a low wear resistance and high values of coefficient of friction. To improve these parameters and due to the fact that many of steels which are utilized for manufacturing of mentioned parts are also categorized as Nitralloy steels, in this paper, the improvement in these properties of chosen steels by the application of plasma nitriding has been studied. The steel equivalent 17Ni4CrMo (i.e., CSN 41 6720) and equivalent 42CrMo4 (i.e., CSN 41 5142) were chosen for the study. The chemical composition of chosen steels was verified by optical emission spectrometry. The microstructure and the diffusion layer were observed by optical microscopy due to the evaluation of layer parameters important for the lifetime. ZWICK ZHU 2.5 was used for a measurement of the universal hardness of the surface and values of graphs of microhardness were obtained by the device LM 247AT LECO from a cross-section of samples. The coefficient of friction was determined by Bruker CERT-UMT-3 with a ball-on-disc method. The parameters of wear paths were obtained by Talysurf CLI 1000. After the application of plasma nitriding technology, the hardness of both steels was rapidly increased in comparison with non-nitrided samples. According to the comparison of coefficients of friction with respect to the parameters of the measurement, the coefficient of friction of nitrided samples decreases with increasing temperature, which is essential knowledge for the weapon industry, especially the construction of bore barrel.

中文翻译：

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军用钢的氮化层的服务行为

随后，必须根据客户要求通过热处理对用于制造军事技术特定零件（例如重型车辆中的发动机曲轴或枪管）的钢进行热处理。尽管通过硬化过程获得的马氏体组织表面较硬，但钢的耐磨性低且摩擦系数值高。为了改善这些参数，并且由于许多用于制造所述零件的钢也被归类为硝态合金钢，在本文中，已经研究了通过等离子渗氮改善所选钢的这些性能的方法。研究选择了钢的当量17Ni4CrMo（即CSN 41 6720）和当量的42CrMo4（即CSN 41 5142）。通过光发射光谱法验证了所选钢的化学成分。通过光学显微镜观察微观结构和扩散层，这是由于评估对于寿命重要的层参数。ZWICK ZHU 2.5用于测量表面的通用硬度，并且通过LM 247AT LECO装置从样品的横截面获得显微硬度的图形值。摩擦系数由Bruker CERT-UMT-3采用圆盘法测定。磨损路径的参数是通过Talysurf CLI 1000获得的。使用等离子渗氮技术后，与非氮化样品相比，两种钢的硬度均迅速提高。根据摩擦系数相对于测量参数的比较，