Spray forming, also known as spray casting, spray deposition and in-situ compaction, is a method of casting near net shape metal components with homogeneous microstructures via the deposition of semi-solid sprayed droplets onto a shaped substrate. In spray forming an alloy is melted, normally in an induction furnace, then the molten metal is slowly poured through a conical tundish into a small-bore ceramic nozzle. The molten metal exits the furnace as a thin free-falling stream and is broken up into droplets by an annular array of gas jets, and these droplets then proceed downwards, accelerated by the gas jets to impact onto a substrate. The process is arranged such that the droplets strike the substrate whilst in the semi-solid condition, this provides sufficient liquid fraction to 'stick' the solid fraction together. Deposition continues, gradually building up a spray formed billet of metal on the substrate.
The gas atomised spray forming (GASF) process typically has a molten alloy flow rate of 1–20 kg/min-1, although twin atomizer systems can achieve metal flow rates of up to 80 kg/min-1. Special steel billets of 1 tonne or more have been produced by spray forming on a commercial basis, together with Ni superalloy ring blanks of up to 500 kg and Al alloy extrusion billets of up to 400 kg.
Read more about Spray Forming: History, Advantages, Disadvantages, Commercialisation, Melting, Atomisation, References
Famous quotes containing the words spray and/or forming:
“I discovered
the colors in the wall that woke
when spray from the hose
played on its pocks and warts....”
—Denise Levertov (b. 1923)
“The structure was designed by an old sea captain who believed that the world would end in a flood. He built a home in the traditional shape of the Ark, inverted, with the roof forming the hull of the proposed vessel. The builder expected that the deluge would cause the house to topple and then reverse itself, floating away on its roof until it should land on some new Ararat.”
—For the State of New Jersey, U.S. public relief program (1935-1943)