Rolling current collector in direct current machines

The new method of rolling current collector has been developed. Its theoretical research was carried out. The operating model sample of the current collecting device using the rolling contact was made

Corrosion Behavior of Welded Joint of Q690 with CMT Twin

Low alloy steel of Q690 was welded with the method of CMT Twin. The corrosion behavior of welded joint had been investigated using scanning vibrating electrode technique (SVET) in 3.5% NaCl solution. The research results showed that the appearance of the troostite increased the hardness of the heat affected zone. Furthermore, the corrosion products of different microstructure were identical, and the white products (Fe(OH)2) of welded joint turned into products of rufous (Fe(OH)3). The quantitative information provided by SVET was discussed, and the corrosion degree was measured by some parameters. In comparison with other areas, the corrosion rates of the overheated zone and the base metal were higher. Then, the corrosion resistance of the weld zone with CMT Twin was greatly improved, when compared with that of the base metal. Therefore, Ni has significant influence on corrosion resistance of weld zone. In summary, it can be discovered that the corrosion rates of various zones were related to the welding heat input

Effects of Welding Heat Input on Microstructure and Electrochemical Behavior of Flux-Cored Arc-Welded Q690 HSLA Steel

In this work, the weld metal (WM) for the Q690 high-strength low-alloy (HSLA) steel was prepared through flux-cored arc welding (FCAW) at 10 kJ/cm and 20 kJ/cm heat inputs. The effect of welding heat input on the relationship between the microstructural factors and the electrochemical behavior of the FCAW Q690 steel was studied. Due to the fine grain and acicular ferrite affected by the 10 kJ/cm low heat input, the WM presented similar electrochemical behavior to the Q690 base metal, which would minimize the risk of galvanic corrosion. Also, at 20 kJ/cm of high welding heat input, the WM with higher-sized bainite structure was prone to galvanic corrosion risk minimization