Steel fiber addition

Table 20 Influence of Steel Fiber Addition on the Properties of Refractory Castables...

The walls of the vessels and the flue gas lines are often lined with medium-strength, medium-density refractories since there are few erosion problems and an acceptable shell temperature is the primary concern. Stainless steel fiber additions to the castable are strongly recommended since they have been shown to reduce maintenance costs. The elbows of the overhead flue gas lines may require better erosion-resistant materials because the flue gas can contain some catalyst dust that escapes from the cyclones. The cyclones are connected to a plenum chamber that is welded to the vessel head. The chamber collects the flue gases from the cyclones and transfers them to the overhead line. The plenum skirt has the same temperature on both sides and expands and contracts as the vessel temperature rises and falls. Castable refractory has been used to... 

Achievement of material ductility by the addition of steel fibers. 

As seen in Fig. 4.22,1 ° the addition of steel fibers into latex-modified systems has a positive effect on the strength with increasing polymer-cement ratio and steel fiber content. In general, the flexural and compressive strengths can be predicted by the following equations f391... 

Nowadays, in place of asbestos, fibrous reinforcements are used that include glass fiber, steel fiber, aramid fiber, potassium titanate fiber, etc. Since these fibrous reinforcements have their own specific properties, in practice, a mixture of them is used. Potassium titanate fiber is a hard inorganic fiber. It can improve the strength, the heat resistance and the wear resistance of the fiietion material. In addition, it can enhance the friction coefficient of the friction material through its abrasive property. 

Other fibers may be used in POs, though some of these may be chosen more for their special properties. Basalt mineral fibers or Kevlar can provide extreme reinforcement for ballistics applications other fibers include metal fibers for electromagnetic shielding purposes (discussed in Chapter 6). However, as in the case of stainless steel fibers, just because an additive is in fiber form does not necessarily mean it provides meaningful mechanical property reinforcement, but it may provide the opposite of what is wanted [6-4, 7-57]. 

In some studies, external loads have been exerted upxin the concrete kept in a NaCl solution under the influence of effective freeze-thaw cycles. The concrete spiedmens expased to NaCl have been shown to lose twice as much weight as those expxised to water. Sp>ecimens with steel fibers lose weight maximum at the w/c ratio of 0.44 that becomes obvious after 20-25 cycles. As the rate of the tension of the burdens exerted increased, resistance of the concrete spjecimens to cycles decreased. Addition of steel fibers in concrete specimens has been shown to cause a delay in a decrease in the performance of the concrete in the advanced cycles in comparison with the concrete without fiber (Sun et al., 2002 Mu et al., 2002 Miao... 

The reinforcement of concrete or mortar by the use of glass or steel fibers results in an improvement in properties such as ultimate flexural strength and toughness, at the expense of compressive strength (Flajsman et al, 1971). However, corrosion of glass or steel by the basic mortar environment or by gases that permeate from the outside creates a problem. In principle, the addition of a polymer to such a reinforced system might be... 

Chen PW, Chung DDL, A comparative study of concretes reinforced with carbon, polyethylene, and steel fibers and their improvement by latex addition, ACl Mater J, 93(2), 129-133, 1996. Walters DG, A comparative study of concretes reinforced with carbon, polyethylene, and steel fibers and their improvement by latex addition. Discussion, ACI Materials Journal, 94(1), 75, 1997. 

A total of four types of recycled fiber plus two types of virgin fiber were used as the reinforcement in concrete. Three recycled fibers were obtained from disposed tires and one from carpet waste. The tire fibers included two types of tire fabrics composed of polymeric tire cords, tire-rubber strips which were the main component of tires, and tire steel fibers which were the radial steel reinforcement of tires. The fibers from carpet waste contained backing fibers (nsually polypropylene), latex adhesive particles, and a small amount of face fibers. In addition, hooked end steel fibers and FiberMesh polypropylene fibers were also used as virgin fibers for comparison. Recycled fiber volume fractions in each composite were fixed at 2% except that the tire steel fiber and the virgin fibers (steel fiber and FiberMesh) were used at a 1 vol%. 

The free shrinkage of concrete with steel fibers was about 7% lower than that of concrete. The free shrinkage of concrete with FiberMesh and recycled polymeric fibers was 23-57% higher than that of concrete. This adverse phenomenon might be attributed to the higher porosity in the composites compared to the plain concrete due to the addition of a large amount of synthetic fibers. 

Interest, academic and Industrial, In Liquid Crystal Polymers (LCP s) was sparked by the commercialization of Kevlar aromatic polyamide fiber In the early 1970 s. [1,2] This fiber can be made almost as stiff and as strong as steel, at one fifth of the density of steel. In addition. It has good resistance to chemical attack and outstanding resistance to heat. From a scientific point of view, LCP s are Interesting because they. In addition to displaying a variety of phenomena and properties seen with conventional Isotropic polymers, also exhibit many of the complex physical properties of small molecule liquid crystals.[3]... 

Volatile iodine species are not efficiently retained by the steel fiber filter. For this reason, an additional filter was proposed containing a silver-impregnated... 

Good electrical conductivity at a lower loading level. CNT, CNF or GNP have proven to be an excellent additive to impart electrical conductivity in the nanocomposite at a lower loading level compared to carbon black, chopped carbon fiber or stainless steel fiber. 

Additives used in final products Fillers barium sulfate, carbon black, carbon fiber, carbon nanotubes, clay, crosslinked PS beads, lead oxide (g-radiation shields), kaolin, magnesium hydroxide, mica, rectorite, silica, sodium aluminum silicate Plasticizers aromatic mineral oil, paraffinic mineral oil, rosin esters, terpene resins Antistatics carbon black, steel fibers, trineoalkoxy amino and trineoalkoxy sulfonyl zirconate Release zinc stearate ... 

Suppliers of metallic flakes and fibers can be found in compilations of industrial material and services such as the Thomas Register. Included in the Thomas Register are Transmet Corporation, Columbus, Ohio, which produces aluminum flakes of uniform size and shape the N.V. Bekaert S.A. and the Interational Steel Wool companies, which produce stainless steel fibers in mat and chopped fiber forms the National-Standard Company, which produces nickel fibers Toshiba Chemical, which produces coated copper fibers, and the 3M Company, which produces thermo-formable EMI-shielding products. In addition, AMOCO and Ashland Chemical Company among others produce carbon fibers, and there are several companies that specialize in supplying metal-coated carbon and metal fibers for customized applications. 

It has long been known that it is possible to modify the electrical properties of polymers by means of conductive admixtures of many kinds or, rather, to make them conductive. Despite this, electrically conductive polymers are still not of any great economic importance as materials. They do, however, play an indispensable role in many specialized technical applications. They are mostly manufactured by incorporating electrically conductive carbon black or carbon fibers in a variety of polymers, especially thermoplastic polymers. Other conductive additives, such as steel fibers, aluminum flakes, metal-coated carbon fibers, metal-coated hollow glass spheres, and low melting metallic alloys have not so far played any decisive part in the development of electrically conductive polymers. 

Early work on the use of foams and mats has been reviewed [9j. Nickel fiber, nickel-plated steel fiber, or nickel-plated graphite fiber mats are preferred because they have smaller pores ( 50(im) [14]. The most recently developed mats can have porosities as high as 95% [13] and are much lighter than the sintered nickel plaques, which typically have porosities between 80 and 90%. Initially, standard cathodic impregnation methods were used to load the active material into the foam [9]. More recently, the preferred method is to incorporate the Ni(OH)2 in the form of a slurry into the mat [13, 14]. This has been called the suspension impregnation method [14]. Considerable improvement in the Ni(OH)2 has been achieved by the addition of divalent Co compounds to the slurry. The best results... 

Fig.8 Compressive Strength of Lightweight Concrete Improved by Addition of Steel fiber...

Fig. 11. The effect of fiber addition on the specific wear rates of a few polymers (2). The rectangular bar chart indicates specific wear rate (units on the left of the graph) and vertical arrows indicate the coefficient of friction (units on the right of the graph). Test conditions are (i) 440°C steel ball (dia. = 9 mm) sliding on polymer specimen, Normal load = 5 N, y = 0.1 m/s, roughness of polymer surface = 400 nm, 30% humidity (72) (ii) test conditions same as for (i) (72) (iii) test conditions same as for (i) (72) (iv) reciprocating-pin-steel plate apparatus, counterface roughness Eg, = 0.051 ixm, N2 environment, (73) (v)) test conditions same as for (iv) (73) (vi) pin-on-steel (AISI02 quench hardened) disk apparatus, counterface roughness = 0.11 um, p = 0.66 MPa, y = 1 m/s (29) (vii) test conditions same as for (vi) (29) (viii) test conditions same as for (vi) (29). Reprinted from Ref. 2.

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