Welding of aluminium

Roberts D K and Wells A A Fusion welding of aluminium alloys, Pt V - A mathematical examination of the effect of bounding planes on the temperature distribution due to welding, Brit Weld] 1 (12) 1954 553-60. 

Aluminium coatings exposed as sprayed show remarkable protective properties and in many cases the only evidence of age is the appearance of small hard nodules of aluminium oxide, and these do not appear to be deleterious. However, the dead white of the sprayed surface soon becomes discoloured by dirt and so a paint covering is usual. A chromate inhibitor is not essential and two coats of a simple vinyl-based sealing paint have given remarkable results in the tests of the American Welding Society over periods of 12 and 15 years. 

On the Figures 1 and 2, the schematical drawings of cells for charge-discharge cycles are shown. On the Fig. 1, the cell in the "soft" pouch, formed by welding of three-layer material (lavsan-aluminium-polyethylene) on polyethylene layer, is shown. 

Thermite welding is used for joining iron rails and also for liberating elements such as W and V from their oxides. The welding process involves heating a mixture of aluminium powder and hematite (thermite) the vigorous reaction which results produces AI2O3 and iron, i. e. 

Tanks. Cmde oil storage tanks are usually constmcted of welded iron, aluminium, or stainless steel. Their sizes vary throughout the industry depending on the refining capacity of the particular plant and the availabihty of incoming cmde oil. Storage tanks with a capacity of 446,000 kg (1 milhon pounds) are not uncommon. 

This reaction of aluminium with ifon(lll) Oxide is called the thermite reaction. It is used to make molten steel for mending and welding broken railway lines the temperature reached is about 2000 °C. The thermite mixture was often used in World War II incendiary bombs, such as those which devastated London, Hamburg and Dresden. 

The role of aluminium in the development of occupational asthma has never been convincingly substantiated. Occupational asthma has been attributed to aluminium welding (16). 

Lutetium-177 was produced by irradiation of lutetium samples in the core of PARR-1, a swimming pool type reactor, at a thermal neutron flux of 1 X 10 n-cm -s for specified periods of time ranging from 1 to 96 h. Naturally abundant LU2O3 and enriched UiiO were dissolved in IM HNO3, evaporated to dryness and reconstituted in O.IM HNO3, and again evaporated to dryness. The Lu(NO3)3 (2.59% Lu) powder and enriched Lu(NO3)3 (68.9% Lu) powder thus obtained were sealed in quartz ampoules and cold welded in aluminium containers for irradiation. In another experiment, quartz ampoules were filled with 0.2 mL of liquid Lu(NO3)3, sealed and cold welded in aluminium containers. These targets were then irradiated in PARR-1. The... 

Samarium-153 was produced by irradiation of samarium samples at a neutron flux of 1 x 10 n cm s in the core of PARR-l. Natural or enriched 52Sm2O3 powder was sealed in quartz ampoules and placed in aluminium containers, which were then cold welded. Irradiated samples were dissolved in IM HNO3 0.2 mL of the solution was evaporated in the quartz ampoule. In another experiment, 0.2 mL of the Sm(NO3)3 solution was placed in quartz ampoules. These ampoules were sealed and cold welded in aluminium containers for irradiation. The irradiated targets were dissolved in 5M HCl and evaporated to dryness. The residue was dissolved in physiological sahne solution and diluted to a specified volume for labelhng studies. 

In this process the arc is struck between a flux-covered consumable electrode and tbe work. Thus method is the most widely used form of arc welding and is used on all materials with the exception of aluminium The flux produces gas which shields the surface of the molten metal and leaves behind a slag which protects the hot metal from the atmosphere while cooling and has to be chipped off when cool. 

In contrast to the aerospace industry (see Aerospace applications), conditions prevailing in automobile manufacture dictate that pre-treatments (see Pre-treatment of aluminium) should have short process times and be tolerant of production variables. The surfaces produced should retain adequate bonding properties during extended storage under poorly controlled conditions. The surface may need to be sufficiently conductive to permit weld-bonding techniques. Pre-treatments applied at the coil stage must be compatible with mill oils and press lubricants, and withstand mechanical deformation in the press. 

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