Hot-extrusion process

Hot Extrusion of Shells. A modification of the Ugine-Sejournet hot extrusion process (using glass as lubricant) is used by Scaife Company of Oakmont, Pennsylvania. In this process a complete shell (such as 4.2 inch) can be produced in one piece from a simple billet. Important features of the development are in the substitution of readily available billet stock for seamless steel tubing, a critical material in times of war. Another feature of this process is that it requires about 25% less steel Refs Ordnance, 38, 753 (1954) 2) Iron Age... 

A hot-extrusion process for fabricating NdFeB permanent magnets was applied by Ma et al. (1987). These authors reported that NdFeB magnets made by extrusion exhibit a [100] fiber texture with the easy magnetization lying randomly in a plane normal to the extrusion direction. Extrusions made with atomized powder were... 

In 1797, Joseph Barmah patented the first extrusion process for making lead pipes. The metal used to be preheated and ram was hand-driven. In 1820, Thomas Burr built the first hydraulic power press that was to extrude lead pipes (Sheppard 2013). The process was called squirting. By the end of nineteenth century, the extmsion methods were also in use for copper and brass alloys. Alexander Dick invented a hot extrusion process for nonferrous metals in 1894. North America has its first aluminum extrusion process in 1904. In 1950s, Sejounet introduced molten glass as lubricant in extmsion process. 

Example As billets made of AA-6060 aluminum chips show similar mechanical and microstructural properties as conventional cast aluminum billets, AA-6060 milling and turning chips can be reused in direct hot extrusion processes without need for reprocessing in a foundry (Tekkaya et al. 2009). 

Hot Extrusion. This term is best reserved for the process of extrusion in which clay that has already been prepared and has the correct water content is heated while passing through the extruder these features distinguish the process from steam tempering (q.v.). The Hot Extrusion process is typified in the extruders designed by the Bedeschi Company, Padova, Italy. 

In the two typical shaft seal manufacturing processes shown in Fig. 2, the extrusion process is only required if the compression molding process is being used. There are basically two types of extruders in general use, the cold feed and the hot feed. In both cases their role is to produce the preforms for use with compression molding. The critical issues with the preform are the shape, the dimensions, and the weight. 

The extrusion process requires the use of a lubricant to prevent adhesion of the aluminum to the die and ingot container walls. In hot extrusion, limited amounts of lubricant are applied to the ram and die face or to the billet ends. For cold extrusion, the container walls, billet surfaces, and die orifice must be lubricated with a thin film of viscous or solid lubricant. The lubricant most commonly used in extrusion is graphite in an oil or water base. A less common technique, spraying liquid nitrogen on the billet prior to extrusion, is also used. The nitrogen vaporizes during the extrusion process and acts as a lubricant. 

The alloys are first produced by rapid solidification and are amorphous in nature. They are either directly fabricated as powders, by a process such as high-pressure gas atomisation (HPGA), or by melt-spinning of ribbons, which are subsequently pulverised to form a powder (<150 /im). The powders are then consolidated by hot extrusion between 950-1050°C where the initial amorphous structure breaks down and forms a fine dispersion of stable borides in a ductile Fe-based matrix. 

Polyethylene. This is essentially a closed-cell insulation manufactured at 448 =t 2 K by an extrusion process. A blowing agent and nucleating agent are employed to control the cell size, and primary use is in insulating pipelines for hot and chilled water lines, air conditioning, and processing... 

Chokshi, R. J., H. K. Sandhu, R. M. Iyer, N. H. Shah, A. W. Malick, and H. Zia. 2005. Characterization of physico-mechanical properties of indomethacin and polymers to assess their suitability for hot-melt extrusion process as a means to manufacture solid dispersion/soJUflbarm ScB4 2463-2474. 

Different extrusion profile processes can be used such as a robotic profile. A robot delivers the hot melt over or around a substrate. This robotic extrusion process can uses a flexible, heated, high-pressure hose that is connected to the extruder s die exit. The hot melt travels through the hose. At the end of the hose is a nozzle the tip of this nozzle is, in effect the actual profile die. A computer-regulated multiaxis robot controls the positioning of the profile nozzle die. The nozzle/die is guided by the robot to deposit the profile s hot melt on, as an example, a substrate that is on a multi-station rotating table supporting other substrates to be covered. 

Hot extrusion is a hot-working process that makes use of the deformability of heated metallic materials to shape them. The process is sited for producing barhke and tubular objects. Most metals and alloys can be extruded. 

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