| 摘要 |
The invention relates to a process and installation for brass-plating the tubesheets in the ship coolers and heaters. According to the invention, the process carries out the plating by heating the brass cuttings or waste which are put onto the steel backing of the plate, above a previously deposited deoxidizing layer such as borax and, upon heating the steel backing by partially submerging it into a salt bath heated at 1200 degree C, the brass melted this way diffuses in a superficial layer therein as a result of maintaining the melting temperature for 20 ... 40 minutes. In order to reduce the thermal stress to minimum, the plated sheet is cooled slowly, at a rate of 100 ... 150 degree C/h up to reaching 300 ... 350 degree C, followed by air cooling. The installation for the application of the process comprises a salt bath (A), a cooling furnace (B), a single girder (C) with an electrical hoisting block (D) and a gripping device (E) and the heating installation containing the salt bath (A) comprises a heatproof enclosure (a) confined by the body of the bath (1) and some covers (2 and 3) driven by some hydraulic cylinders (4 and 5), some electrodes (49, 50 and 51) being immersed into the salt bath they heat in order to melt the salt and heat it to the temperature of 1200 degree C, the electric resistance being formed between the electrode ends, on the shortest paths, and for the uniform bath heating, through the construction of the electrodes (49, 50 and 51), namely the trifurcation thereof, there are provided six heating resistances R 1 ... R 6, that is the resistances R 1, R 2 and R 3 in the centre of the bath and the resistances R 4, R 5 and R 6 at the periphery of the bath, this electrode structure eliminating the cold spots which occur at the periphery of the bath upon the use of the classical electrode construction.
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