Apparatus and process for spraying molten metal

摘要

In a process and apparatus of arc spraying, a fusible metal electrode wire is fed progressively into an arc chamber through a current contact member towards a nozzle outlet, an arc being formed between the tip of the electrode wire and the nozzle and an annular stream of gas flowing coaxially of the electrode wire is directed to converge at the wire tip. As shown in the drawing the torch 1 is mounted on a holder 2 through which shielding gas and cooling water are supplied and the electrode wire guide 6 consists of tube 4 and current contact member 9 which directs the wire 5 into the arc chamber 7. The exit nozzle 8 has a converging part 14 leading to the nozzle outlet 15 of frustoconical section diverging at 30 degrees and leading into part 16 which diverges at 90 degrees. A gas directing nozzle 11 coaxially surrounds member 9 and directs a shielding gas such as argon to the wire tip. Further gas such as a reactive gas may be introduced via inlet 17. Mild steel plates may be sprayed with low carbon low alloy steel or stainless steel or tungsten or molybdenum. Powders may also be introduced into the arc via inlet 17 to produce alloy or cermet coatings.