play it in carbon composite for nozzle desoudage under atmosphere of gas burners

摘要

1373501 Welding by fusion PFIZER Inc 21 Oct 1971 [8 Jan 1971] 49081/71 Heading B3R [Also in Division H5] In a gas-shielded consumable or non-consumable electrode arc-welding torch, a tubular shielding gas nozzle surrounding the electrode has a lining insert 36 comprising a tubular base coated or impregnated with pyrolytic carbon, whereby build-up of weld spatter in said nozzle is reduced and removal of said spatter is facilitated. The insert 36 may comprise: Example I, a polycrystalline graphite cylinder machined from rod stock and coated with pyrolytic graphite using flowing methane at 2100‹ C. at 5 mm. Hg. abs.; Example II, a carbonized rayon needled felt or cloth impregnated with pyrolytic carbon, such an insert being produced by processing sheets of the carbonized felt using flowing methane at 1100‹ C. at 5mm. Hg. abs. for 20 hours rolling and machining the sheets into right cylinder configuration, and then further processing under the same conditions for 60 hours, or by pyrolytic carbon impregnating initially tubular formed fe or Example III the impregnated felt of Example II coated with pyrolytic graphite by the process of Example I. As shown, an Example I insert is secured in the nozzle 30, e.g. of copper, by clamping, swaging, brazing, cementing or press and shrink fitting. The nozzle 30 is removably screwthreaded into a heat sink nose 24 of a consumable wire electrode torch. In Figs. 3, 4 (not shown), an Example III insert is provided in a nozzle which is retained in the torch nose by a collet chuck comprising a contractable elastomeric 0-ring. The torches may be for TIG, MIG or CO 2 - shielded welding. Gases referred to are CO 2 , A.