The effect of manual electric arc surfacing modes of low-alloy 09G2S steel by T-590 electrodes on their structure and hardness has been investigated. It is shown that pulse-arc surfacing of coatings by electrodes forms a fine-dendritic structure of the deposited metal. The microstructure of the heat-affected zone after surfacing consists of several regions: the overheating zone with a Widmanstätten structure and the normalization zone with a characteristic fine-grained ferrite-perlite structure. In the initial state, the base metal (09G2S steel) has a hardness of ~2500 MPa. The hardness of the deposited coating material due to strong mixing with steel is ~2700–3000 MPa and 2100–2300 MPa for the thermal impact zone. When coating in a DC mode, the heating temperature of the surfacing bath is higher, causing grain growth. When coating in pulse modes, a structure with smaller sizes of components is formed by directed low-frequency high-energy impact of the electric arc on the formed metal and due to the constant reciprocating motion of the melt with the frequency of current modulation. It is established that the application of the pulse-arc surfacing method enables preserving the previously formed hardening phases in deposited coatings.

中文翻译：

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低频电流调制沉积在低碳钢上的耐磨涂层的结构和硬度

研究了用T-590焊条手工电弧堆焊低合金09G2S钢的方式对其结构和硬度的影响。结果表明，电极对涂层的脉冲电弧堆焊形成了沉积金属的细枝晶结构。堆焊后热影响区的微观结构由几个区域组成：具有 Widmanstätten 结构的过热区和具有特征细晶铁素体-珍珠岩结构的正火区。在初始状态下，母材（09G2S 钢）的硬度约为 2500 MPa。由于与钢强烈混合，沉积涂层材料的硬度为~2700-3000 MPa，热冲击区为 2100-2300 MPa。在直流模式下涂层时，堆焊池的加热温度较高，导致晶粒长大。在脉冲模式下镀膜时，通过电弧对成形金属的定向低频高能冲击以及熔体以电流调制频率的恒定往复运动，形成具有较小尺寸部件的结构。已经确定，脉冲电弧堆焊方法的应用能够保留沉积涂层中先前形成的硬化相。