Cast liners

The hot-feed rubber extruder is usually characterised by a relatively large screw depth and a relatively short L/D ratio of the barrel of 3 to 8 1 with the greatest number of machines having a ratio of 4 1. The barrel comprises usually a cast iron outer with either a traditional replaceable nitride liner, or, in the case of one manufacturer, of a single piece construction with an integral cast liner which has a surface hardness of Rockwell C60-62 and a hardness depth of 1.5 mm. The functional life for the bimetallic barrels is longer than for conventional nitride liner systems. 

In contrast to the basic refractory services provided by their predecessors, today s gunited or cast liners are much more dependent upon the ability of the applied material to resist possible chemical attack. Additionally, the fact that the cementitious materials utilized in these applications are somewhat absorptive and brittle causes another type of concern which should also be considered when they are specified for "wet" chimneys. (Figure 48-8 illustrates a gunned lining placed over a membrane as a lining of a concrete shell. This same design may be followed in application to a steel liner.)... 

SAE G4000 F10008 3.0-3.3 C, 2.0 Si, 0.8 Mn Pearlite 276 (40) -Ductile (Nodular) Iron Diesel engine castings, liners, cylinders, and pistons... 

Expanded vinyl has been used as a pressure-sensitive tape backing for many years. Typically, a low-density foam is plastisol-coated on a casting liner that is used a number of times, or onto a continuous belt. After fusion and expansion, one or both sides are transfer-coated with adhesive that has been dried (and sometimes... 

Similar behaviour occurs when trying to locate voids in concrete cast behind steel plates, e g. the steel liner in nuclear containment walls. Our own experience has shown that in the case of a steel liner (encast at depth 250 mm) the reflected compression waves are dominant regardless of the condition of the concrete behind the plate. 

Propellants cast into rockets are commonly case-bonded to the motors to achieve maximum volumetric loading density. The interior of the motor is thoroughly cleaned, coated using an insulating material, and then lined with a composition to which the propellant binder adheres under the environmental stresses of the system. The insulation material is generally a mbber-type composition, filled with siUca, titanium dioxide, or potassium titanate. SiUca-filled nitrate mbber and vulcanizable ethylene—propylene mbber have been used. The liner generally consists of the same base polymer as is used in the propellant. It is usually appHed in a thin layer, and may be partially or fully cured before the propellant is poured into the rocket. 

An important appHcation of MMCs in the automotive area is in diesel piston crowns (53). This appHcation involves incorporation of short fibers of alumina or alumina—siHca in the crown of the piston. The conventional diesel engine piston has an Al—Si casting alloy with a crown made of a nickel cast iron. The replacement of the nickel cast iron by aluminum matrix composite results in a lighter, more abrasion resistant, and cheaper product. Another appHcation in the automotive sector involves the use of carbon fiber and alumina particles in an aluminum matrix for use as cylinder liners in the Prelude model of Honda Motor Co. 

Cellulose liner material absorbs water and needs to be wet for at least 30 s prior to investing to prevent Uquid from being extracted from the investment. The ceUulose liner bums when heated in air and is eliminated completely from the mold at burnout temperatures of 700°C (123). To ensure retention of the mold within the casting ring, a ceUulose liner should be kept short of each end. For gypsum investments a liner that is 12 mm shorter than the height of the ring should be used. 

The thermal stabiUty of epoxy phenol—novolak resins is useful in adhesives, stmctural and electrical laminates, coatings, castings, and encapsulations for elevated temperature service (Table 3). Filament-wound pipe and storage tanks, liners for pumps and other chemical process equipment, and corrosion-resistant coatings are typical appHcations using the chemically resistant properties of epoxy novolak resins. 

Crete piping systems can be lined with special salt-glazed vitrified-clay liner plates, joined with a die-cast aspnalt joint. Concrete pressure pipe is competitive with cement-lined ductile iron for underground plant water systems. 

Maintenance The only moving parts in spiral concentrators are those in the pumps that supply the feed and recirculate intermediate products. However, there are sometimes minor maintenance problems associated with the spiral trough itself. Some ores contain sharp particles of veiy abrasive minerals. The presence of these minerals in some ore causes rapid formation of deep grooves in the surface of cast-iron spirals. Wear grooves can be patched with a variety of plastic and metallic cements. Most spirals presently in service are made of cast iron with molded and vulcanized liners. These liners have successfully solved most wear problems. 

White cast iron is brittle and difficult to machine. It is made by controlling the composition and rate of solidification of the molten iron so that all the carbon is present in the combined form. Very abrasive- and wear-resistant, white cast iron is used as liners and for grinding balls, dies, and pump impellers. 

Vibration appears/disappears suddenly with mcreasmg/decreasmg speed, respectively. Loose component Rotor sleeves/impellers become loose as speed is increased Bearing liners, housings, or selfaligning spherical casts have loose fits Loose casing or supports... 

The stator vanes are usually not shrouded. This is not a hard and Iasi rule In practice, often vanes are mixed with some shrouded and some unshrouded. When a separate stator inner case is used, it is normally ot cast iron. If the temperature is expected to exceed 500°F, the liner will be multipart with the discharge end being made of steel. 

Amongst the products made by polymerisation casting are propellers for small marine craft, conveyor buckets used in the mining industry, liners for coal washing equipment and main drive gears for use in the textile and papermaking industries. 

The white cast irons and their low alloys have good abrasion resistance properties [2,3]. White cast irons are used for grinding balls, segments for mill liners and slurry pumps. In the ceramic industry they are used for muller tyres and augers in the pulp and paper industry for attrition mill plates and chip feeders and in the paint industry for balls for grinding pigments. 

Figure 12-2F. Typical liner-type cast iron cylinder. (Used by permission Ingersoll-Rand Company.)...

TYPICAL LINER-TYPE CAST-IRON CYLINDER... 

DRY-TYPE LINER is a special cast-iron, full length of the cylinder, shrunk in place, and securely locked against any movement. PISTON is usually cast-iron, locked on the rod between a solid collar and a nut. If a cylinder size is such that sufficient piston wall thickness is not available, the piston and rod are forged integrally as shown, and special inserted rider rings are included to improve wearing qualities. 

Figure 12-2T. Medium- or high-pressure, double-acting cylinder with flanged liner. The liner is locked in place by a flange between head and cylinder barrel. A step on the liner O.D. permits easy insertion. The cylinder may be made of cast-iron, nodular iron, or cast steel, depending on operating pressure. Note Optional two-compartment distance piece (type D) designed to contain flammable, hazardous, or toxic gases is illustrated. (Used by permission Bui. 33640, June 1985. Dresser-Rand Company.)...

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