Spray-welding

In recent years, the spraying process has been adapted for hard facing, using the chromium-nickel-boron alloys which have become known as Colmonoy. More recently still, the cobalt-base Stellite alloys have also been used. These materials in powder form are sprayed on to the surface in the usual way. The deposit is afterwards heat treated by a torch, so that fusion takes place. The process is often known as spray-welding. Such coatings are primarily used for hard facing under wear conditions, but as the Anal surface is nickel-chromium or cobalt-chromium they exhibit very high anticorrosive properties. 

Bailey, J. C.. Porter, F. C. and Round, M., Metal Spraying of Zinc and Aluminium in the United Kingdom , in 12th Int. Conf. on Thermal Spraying, Welding Institute, London, paper 8, pp. 1-8 (1989)... 

Air-borne Sealing. A process for the general, as opposed to local (cf. spray welding), repair of a gas retort by blowing refractory powder into the sealed retort, while it is hot the powder builds up within any cracks in the refractory brickwork and effectively seals them against gas leakage. (West s Gas Improvement Co. Ltd., Brit. Pat. 568159 21/3/45.)... 

Blow Mould. The metal mould in which blown glass-ware is given its final shape. Blow pipe Spray Welding. See spray... 

Hot Patching. The repair of the refractory lining of a furnace while it is still hot this is most commonly done by spraying a refractory slurry through a cement gun. See also air-borne SEALING and SPRAY WELDING. 

Spray Welding. A process for the localized repair of cracks in the refractory brickwork of a gas retort or coke oven a refractory powder is carried by a stream of oxygen into an oxy/coal-gas flame so that the powder fuses on the brickwork to seal the selected damaged area on which it is projected. This technique was first used by T. F. E. Rhead, City of Birmingham Gas Dept. 

Tables 15 and 16 compare thermal spraying, welding, and electroplating.

The system has recently been used with success for inspection of 11 inclined nozzle welds during the R1 SPRINT project at Vattenfall Ringhals, Sweden during the summer 1997. At the moment a full system and personal qualification is prepared for inspection of the pressurizer spray nozzle weld at Vattenfall Ringhals, block 2 at May, 1998. 

Laser sensors Laser spray Laser surgery Laser video disks LaserVision Laser welding... 

Plasma arc cutting Plasma-arc devices Plasma-arc furnace Plasma arc spray Plasma arc welding... 

In gas metal-arc, also called metal inert gas (MIG) welding, the arc is stmck between the workpiece and a metal electrode that is consumed as it is transferred in the form of molten droplets across the arc into the weld joint. Using a predominantiy argon shield gas, the droplets are transferred with Httie radial dispersion. Using pure helium, on the other hand, the droplets are larger and have more of a tendency to spray radially from the arc s axis. 

Ziac foil coated with a conductive, pressure-sensitive adhesive is used for repair of other ziac coatings or for imparting corrosion resistance at field sites. The 0.08-mm ziac tape or sheet has a 0.025-mm coaductive adhesive. The laminate is cut to size and pressed tightly to activate the adhesive. Conductive tape can be wrapped around pipe, especially around welds or connections. The corrosion resistance of this material is iatermediate between galvanized or thermally sprayed coatings and zinc-filled paints (21,50). 

Chromium carbide is important in powder preparations designed for thermal spray apphcations of corrosion and wear-resistant coatings on tool and machine parts. Lower carbon carbides of chromium are important in hardfacing tods and electrodes for weld-apphed ovedays on machine wear surfaces. However, these carbides are usually formed in situ from Cr and C in the rod and not added as preformed carbides. The properties of Ci2C2 are hsted in Table 2. 

Released at low velocity into moderately still air Spray booths Intermittent container filling Low-speed conveyor transfers Welding Plating Pickling 0.51-1.02... 

Released at Imv velocity into rnodcTarciv srill air Spray booths, intermittent container filling, low-speed conveyor transfer, welding, plating, pickimg 0,5- l. 0... 

In general, the Aaberg principle is suitable for all open processes which demand an open work area. These processes avoid the use of closed or partially closed systems, for instance a conventional hood with specific walls around the pollution source. In particular, the principle is very suitable for welding (i.e., spraying particle sources) or hot sources of contaminant. Some examples of open... 

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