During the manufacturing of continuous welded rail track, the problem of the local hardened points in the welded joint during rail joint welding is resolved by using local heat treatment of the welded joint. As a result, the quenching structure formation is excluded. However, the appearance of new heat-affected zones with reduced hardness is possible. During operation, such rails are characterized by increased tread surface wear in these areas and rail flattening at the welded joint, which is the main reason for retiring the rails from service earlier than the guaranteed service life. A new technology based on the dependence of the structural component dispersion (primarily perlite and carbide particles formed in the process of rail butt welding) is proposed for the steel composition and cooling conditions. The cooling rate has a decisive influence on the dispersion degree of the ferrite-cementite structure formed during the austenite decomposition. During the welding rail process, the granular perlite formation is possible in a butt weld in areas with a temperature ranging within points Ac1 and Acm. To determine these critical temperatures, thermodynamic calculations were performed using the Thermo–Calc® software (TCFE database) allowing the chemical composition of the samples obtained by spectrometry. The iron–carbon state diagrams for rail steel 76KhSF with the minimum and maximum alloying element content according to GOST R 51685–2013 are modeled. To obtain the minimum number of sections with reduced hardness, it is possible to weld rails using shot discontinuous flash welding. In order to eliminate the formation of defective areas with a quenching structure, it is possible to control the cooling of the welded joint by contact heating. Temperature distribution measurement during welding according to given modes and controlled cooling confirms the theoretical conclusions.

中文翻译：

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差热强化钢轨焊接的开发和建模：焊接和局部热处理建模

在连续焊接钢轨制造过程中，通过对焊接接头进行局部热处理，解决了钢轨接头焊接时焊接接头局部硬化点的问题。结果，排除了淬火结构的形成。但是，可能会出现硬度降低的新热影响区。在运行过程中，此类钢轨的特点是这些区域的胎面磨损增加，焊接接头处钢轨变平，这是钢轨在保证使用寿命之前退役的主要原因。针对钢的成分和冷却条件，提出了一种基于结构组分分布（主要是钢轨对接焊接过程中形成的珍珠岩和碳化物颗粒）依赖性的新技术。冷却速度对奥氏体分解过程中形成的铁素体-渗碳体组织的分散程度有决定性影响。在焊接钢轨过程中，在温度范围在 Ac1 和 Acm 之间的区域的对接焊缝中可能会形成粒状珍珠岩。为了确定这些临界温度，使用 Thermo–Calc® 软件（TCFE 数据库）进行热力学计算，允许通过光谱法获得样品的化学成分。根据 GOST R 51685-2013 对具有最小和最大合金元素含量的轨道钢 76KhSF 的铁-碳状态图进行建模。为了获得最少数量的硬度降低的部分，可以使用不连续闪光焊来焊接钢轨。为了消除淬火组织缺陷区域的形成，可以通过接触加热来控制焊接接头的冷却。根据给定模式和受控冷却焊接过程中的温度分布测量证实了理论结论。