Steel extrusion

This volume not only brings a comparative description of presses, press drives, press controls, auxiliary equipment, and tooling, but also indicates details of design and calculation which are the result of practical experience. In order to limit the scope of this book, such auxiliary equipment as runout and cooling beds, extrusion pullers, materialhandling equipment, stretchers, bar breakers, cable take-up stands, wire coders, etc., has been excluded. Special presses as used for cold extrusion, extrusion of special alloys, etc., and steel extrusion presses will receive separate treatment in a later, enlarged edition. 

Extrusion. The filtered, preheated polymer solution is deHvered to the spinneret for extmsion at constant volume by accurate metering pumps. The spinnerets are of stainless steel or another suitable metal and may contain from thirteen to several hundred precision-made holes to provide a fiber of desired si2e and shape. AuxUiary filters are inserted in front of the fixture that holds the spinneret and in the spinneret itself to remove any residual particulate matter in the extmsion solution. 

Figure 9.16 depicts the arrangement of connections in the extrusion barrel cooling jacket. Embrittlement and cracking of these stainless steel connections (Figs. 9.17 and 9.18) were occurring as frequently as every 4 to 6 weeks. 

BODY COLD FORMING STEEL IMPACT EXTRUSION... 

Maraging steels have found varied uses in the aerospace and aircraft industries. These uses have included rocket motor cases, landing gear components, aircraft forgings and fasteners. Other areas of usage include machine tool and die applications, and extrusion hardware. Marine uses include hydrofoil foil systems and aircraft arrester hooks. 

First part Roller train, stainless steel roUs, diameter 50 mm, pneumatical pivoting to get acces to the extrusion head, length approximately 0.7 m... 

An interesting development initiated by Neste and Norsk Hydro is a multilayer coating for the insulation of deep-water pipelines. The steel pipe is protected by a layer of solid thermoplastic, a core of polypropylene foam and a coating of solid plastic, all of which are built up by cross head extrusion. 

Casting, continuous sheet casting between stainless-steel belts, pouring and several methods in the molten state are usable extrusion, injection, compression, thermoforming, co-injection, machining, welding. Specific grades of PMI can be foamed. 

Four complete extrusion lines for the manufacture of PE pipes are described which are to be supplied by Battenfeld for Moscow s district heating system. The heating system utilises freely layable steel pipes the conveying the superheated steam, the steel pipes being protected and insulated by means of the PE pipes. The cavity is filled with an insulating layer of PU foam. 

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... 

Extrusion is primarily used for lower-melting point, nonferrous metals (see Table 7.2) but with the aid of lubricants and improvements in presses, the extrusion of steel has become available. Most carbon steels and stainless steels are extruded at temperatures of about 1200°C, in which glass is used as a lubricant. Glass is inexpensive, easy... 

Extruders are devices for loading by extrusion (qv) metals, plastics, expls and pyrotechnic compositions. For example, expls such as some Amatols, Explosive D, Compositions A C, etc which cannot be cast-loaded can be loaded by pressing them thru a steel tube by means of a worm screw working inside. 

A spider s orb-web is formed by extrusion of a concentrated protein solution and stretching of the resulting fiber. The cross-strands, which are stronger than steel, resemble silkworm silk. The molecules contain microcrystalline p sheet domains that are rich in Gly-Ala repeats as well as polyalanine segments. The capture spiral is formed from much more elastic molecules that contain many -tum-forming sequences. These assume a springlike p spiral. See Box 2-B. 

Note As the metal in current cast steel or cold extrusion shells is less porous than heretofore, there is a tendency to eliminate base covers, especially in smaller caliber shells(Ref 4)... 

In the cold extrusion process a piece of metal (such as steel) is forced to flow, at room temperature, under high, rapidly applied pressure, thru an orifice of the die. This produces a tubular object of the desired size... 

General descriptions of the cold working process are given in Refs 3, 4, 5, 6 7. Its modification known as impact extrusion has been used mostly for shaping nonferrous metals (Ref 11), but can be used also for iron or steel... 

Cold shaping of steel by compression reaches commercial application) 5)H.J.Pessl 8c H.H.Hautmann, Iron Age, 1953 (August), 69-73 (Factors influencing cold extrusion of steel) 6)T.Bishop, Iron Age 1953 (August), 74 7 (Tools lubricants and steels for cold extrusion) 7)J. G.Henderson 8c J.M.Bates, "Metallurgical Dictionary", Reinhold, NY (1953), 77-8 8)W.C. Tucker, Ordn 38, 458 (1953) (Examples of ammunition articles manufd at present by the cold extrusion process) 9)Battelle Memorial Institute, "Shaping of Steel by Extrusion Method", Frank-ford Arsenal, Philadelphia, Pa, 31. July, 1954... 

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