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Spray forming

About: Spray forming is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 12869 citations. The topic is also known as: spray casting & spray deposition.


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Journal ArticleDOI
TL;DR: The spray forming (SF) process as mentioned in this paper is an improved Osprey process, which was designed at Ospreys Ltd. in the early 1970s and was used to produce ingots from various steels and alloys.
Abstract: Tools for cold forming of materials are used to produce articles made of metals and ceramic materials by cold drawing, embossing, drifting, forging, knurling a thread, and so on. Apart from a high strength, the tool material in this case must also have high abrasive and adhesive wear resistance. When a tool interacts with high-strength abrasive particles, abrasive wear takes place: it is characteristic of processing of ceramics, when high-strength ceramic particles penetrate into a meat surface and form microgrooves in it. In this case, large carbide particles present in a metal hinder this process better than small carbide particles [1]. Adhesive wear takes place when metal is in contact with a metal: microbonds appear between the tool and processed-metal surfaces at contact microareas because of high pressures, and metallic microparticles are torn out from the tool. Adhesive wear can combine with abrasive wear, which is related to the presence of ceramic particles in the metal to be processed. Therefore, high-hardness carbides (VC etc.) in a tool intended for cold metal and ceramic working without cutting should provide an optimum combination of hardness and abrasive wear resistance. In this case, large carbides in a tool metal are favorable for wear as compared to small carbides. However, as the carbide size increases, the metal hardness decreases. In other words, neither a traditional “ingot” metal with large carbides and a low hardness nor a powdered (granulated) metal with a high hardness and small carbides can provide an optimum combination of the functional properties of a certain tool. Therefore, in the last decade, metallurgists have focused their attention on the production of ingots by a nontraditional spray deposition method [2], namely, a spray forming (SF) process. Specifically, they use spray forming to produce a radically new type of ingots, i.e., deposited ingots. The quality of the SF metal is so high that this process is now one of the most dynamically developed high-quality metallurgy processes all over the world. The SF process is used to produce ingots from various steels and alloys, as well as from nonferrous metals. This process has attracted the particular attention of the manufacturers of tool cold-working metal, since it can form spherical primary carbides whose sizes are smaller than those in the metal of traditional ingots and large than those in the metal of gas-sprayed powders. In other words, the SF metal has the optimum combination of hardness and wear resistance that cannot be achieved by other methods of producing a tool metal. The SF process is an improved Osprey process [2, 3], which was designed at Osprey Metals Ltd. (Great Britain). In the course of the conventional Osprey process, a metal‐gas torch is directed into a mold during gas spraying, where semiliquid metal drops solidify layer-by-layer and form an ingot. The mold is fixed in this process. In the SF process, a mold or a crystallizer is absent. A metal‐gas torch is directed onto a gas-cooled rotating metallic disk, which serves as a seed for freezing (deposition) of an ingot. The seed is rotated and pulled down at a speed so that the distance between the spraying focus and the center of the deposited surface is unchanged. Although the rate of rotation was indicated, we can assume by analogy with a two-electrode VADER process that it ranges from 80 to 120 rpm.
Patent
21 Dec 2018
TL;DR: In this paper, a precision-molding method for a metal part additive is proposed, which consists of three steps: dividing the surface of a part into a surface to be processed and a non-machined surface, and manufacturing a casting mold corresponding to the nonmachining surface, wherein the casting mold is manufactured by 3D printing and molding.
Abstract: The invention discloses a precision-molding method for a metal part additive. The method comprises the following steps: step 1, dividing the surface of a metal part into a surface to be processed anda non-machined surface, and manufacturing a casting mold corresponding to the non-machined surface, wherein the casting mold is manufactured by 3D printing and molding; step 2, by adopting a uniform metal droplet ejection technology, spraying metal droplets to a bottom plate of the casting mold layer by layer through a nozzle until the spraying is completed; step 3, molding, standing and cooling,demoulding and cleaning a molded part. According to the invention, by combining the casting mold through 3D printing and the uniform metal droplet spray forming technology, the metal part can be directly precision-molded, and the dimensional accuracy, surface quality, internal quality and quality stability of the molded metal part are high than those by traditional casting methods.
Journal ArticleDOI
TL;DR: In this paper , the compression strength, hardness and tribological properties of the aluminum alloy produced by die cast and spray formed technique were studied as per the ASTM test standards and recorded the average values.
Abstract: Aluminum with –2.5wt.% Cu–2.5wt.% Mg – 5wt.% Zn alloy was synthesized by die cast and spray formed technique. The average density of die cast and spray formed Al alloy was measured by water displacement method. The compression strength, hardness and tribological properties of the Al alloy produced by die cast and spray formed technique was studied as per the ASTM test standards and recorded the average values. The surface morphology of die cast Al alloy depicts the dendritic structures and spray formed Al alloy contains the equiaxed grains, coarse grains and fine grains across the surface. The elemental analysis of both die cast and spray formed Al alloy was measured by using scanning electron microscope. Average percentage of porosity of die cast and spray formed aluminum alloy is 1.79 ± 0.23 and 1.10 ± 0.3 respectively. The hardness of spray formed Al alloy is 10.54 % lesser than that of die cast Al alloy. Average ultimate compression strength of spray formed and die cast Al alloys are 360.07 ± 9.58 MPa and 353.33 ± 5.56 MPa respectively. The study also recorded the wear rate and coefficient of friction of die cast and spray formed Al alloy at different load and speed conditions. The precipitation strengthening mechanism is found to be involved in spray formed alloy.
Journal ArticleDOI
TL;DR: In this article , microstructural studies of spray deposited Al-6Si alloys with different lead content are conducted for 0% and 40% of rolling deformation, and fine equiaxed grain morphology is observed with a uniform distribution of Pb and Si phase in an Al-matrix.
Abstract: In the present work, the microstructural studies of spray deposited Al-6Si alloys with different lead content are conducted for 0% and 40% of rolling deformation. SEM and Optical micrographs are taken for different percentage of lead content. Fine equiaxed grain morphology is observed with a uniform distribution of Pb and Si phase in an Al-matrix and it is found from the microstructures that the size of Pb particles increased with the increase in Pb content. Grains are stretched out in the rolling direction after cold rolling. Pore size is found to decrease after 40% rolling reduction, however, it is increased with the increase in Pb content.

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202310
202216
202117
202037
201933
201826