Plastic behavior, steel

The plastic behavior of coal is of practical importance for semiquantitative evaluation of metallurgical coal and coal blends used in the production of coke for the steel industry. When bituminous coals are heated in the absence of air over the range 300 to 550°C (570 to 1020°F), volatile materials are released and the solid coal particles soften, to become a plasticlike mass that swells and eventually resolidifies. 

The term plastic is not a definitive one. Metals, for instance, are also permanently deformable and therefore have a plastic behavior. Ho v else could roll aluminum be made into foil for kitchen use, or tungsten wire be drawn into a filament for an incandescent light bulb, or a 90 ton ingot of steel be forged into a rotor for a generator. Likewise the different glasses, which contain compounds of metals and nonmetals, can be permanently shaped at high temperatures. These cousins to polymers and plastics are not considered plastics within the plastic industry. 

One device relies on the plastic behavior of steel and consists of a metallic element designed to achieve lower capacity than the standard tie to... 

Whole steel frame is eventually stiffened, and the zone panel deformation is eliminated using this type of connections due to the increased stiffness of the side plates that ultimately provide the three panel zones. This connection system uses aU fillet-welded fabrication which predominately carries all shear actions as well as moments through the combination of vertical shear plates and fillet welds. The side plates should be designed with sufficient strength and stiffness to force aU significant plastic behavior of the connection system into the beam. 

The 18-8 stainless steels pit severely in fatty acids, salt brines, and salt solutions. Often the solution for such chronic behavior is to switch to plastics or glass fibers that do not pit because they are made of more inert material. 

The properties of the lamina constituents, the fibers and the matrix, have been only briefly discussed so far. Their stress-strain behavior is typified as one of the four classes depicted in Figure 1-8. Fibers generally exhibit linear elastic behavior, although reinforcing steel bars in concrete are more nearly elastic-pertectly plastic. Aluminum, as well as... 

As these problems were encountered in the past, it became evident that we did not have at hand the physical or mathematical description of the behavior of materials necessary to produce realistic solutions. Thus, during the past half century, there has been considerable effort expended toward the generation of both experimental data on the static and dynamic mechanical response of materials (steel, plastic, etc.) as well as the formulation of realistic constitutive theories (Appendix A PLASTICS DESIGN TOOLBOX). 

For those not familiar with this type information recognize that the viscoelastic behavior of plastics shows that their deformations are dependent on such factors as the time under load and temperature conditions. Therefore, when structural (load bearing) plastic products are to be designed, it must be remembered that the standard equations that have been historically available for designing steel springs, beams, plates, cylinders, etc. have all been derived under the assumptions that (1) the strains are small, (2) the modulus is constant, (3) the strains are independent of the loading rate or history and are immediately reversible, (4) the material is isotropic, and (5) the material behaves in the same way in tension and compression. 

The behavior of materials (plastics, steels, etc.) under dynamic loads is important in certain mechanical analyses of design problems. Unfortunately, sometimes the engineering design is based on the static loading properties of the material rather than dynamic properties. Quite often this means over-design at best and incorrect design resulting... 

The behavior of materials, particularly steel, in cavitating fluids results in an erosion mechanism, including mechanical erosion and electrochemical corrosion. The straightforward way to fight cavitation is to use hardened materials, chromium, chrome-nickel compounds, or elastomeric plastics. Other cures are to reduce the vapor pressure with additives, reduce the turbulence, change the liquid s temperature, or add air to act as a cushion for the collapsing bubbles. 

Plastic material suppliers provide material data sheets for each grade they produce. At first glance, there could be a tendency to apply the plastic information in a similar fashion to that of other materials. If such a procedure were to be followed, the result would not only lead to disappointment but also perhaps even to failure for many products. The reason for the difference in treating the plastic data sheets from those of other materials is the behavior of plastics under load and under varying environmental conditions, which normally are not factors with other materials such as steel (Chapter 2). 

Plastics are no different in this respect than other materials. If steel, aluminum, and ceramics were to be made into a different complex shapes and no prior history on their behavior for that processing shape existed, a period of trial and error would be required to ensure their meeting the required measurements. If relevant processing information or experience did exist, it would be possible for these metallic (or plastic) products to meet the requirements with the first product produced. Experience on new steel shapes always took trial and error time that included different shaped high pressure hydraulic steel cylinders that failed in service when used in a new injection molding hydraulically operating machine (author s experience). 

The basic approach in designing any product made from any material (steel, aluminum, wood, plastic, etc.) involves knowing the behaviors and characteristics of the materials and manufacturing influences on the materials. In turn this knowledge is to be correctly applied such as using, when required, the processed material s static and/or dynamic properties. Should a need arise for data at conditions different from those at which test data are available, with few exceptions, it would not be too difficult or costly to obtain. 

Because melts have different properties and there are many ways to control processes, detailed factual predictions of final output are difficult to arrive. Research and hands-on operation have been directed mainly at explaining the behavior of melts or plastics like with other materials (steel, glass, and so on). Modem equipment and controls are overcoming some of this unpredictability. Ideally, processes and equipment should be designed to take advantage of the novel properties of plastics rather than to overcome them. 

Coal tar epoxy and plasticized chlorinated rubber laquer coated on mild steel were studied by Scantlebury et al (28). Impedance plots show a gradual decrease in the value of R t and the onset of Warburg-type behavior with increasing Immersion time in 3 weight percent sodium chloride solution. Appearance of an inductive loop when the coal-tar epoxy had a pin-hole was clearly demonstrated. 

Refs 1) L.G. Green, A-M. Weston, and J.H. van Velkinburg, "Mechanical Behavior of Plastic-Bonded Explosives Vertically Dropped on a Smooth, Rigid, Steel Target Surface , LLL Rept UCRL-51022 (1971) 2) Ibid, "Mechanical... 

This physical behavior of the plastics is very important due to the fact that in practice the steel car body and... 

Materials such as metals, alloys, steels and plastics form the theme of the fourth chapter. The behavior and use of cast irons, low alloy carbon steels and their application in atmospheric corrosion, fresh waters, seawater and soils are presented. This is followed by a discussion of stainless steels, martensitic steels and duplex steels and their behavior in various media. Aluminum and its alloys and their corrosion behavior in acids, fresh water, seawater, outdoor atmospheres and soils, copper and its alloys and their corrosion resistance in various media, nickel and its alloys and their corrosion behavior in various industrial environments, titanium and its alloys and their performance in various chemical environments, cobalt alloys and their applications, corrosion behavior of lead and its alloys, magnesium and its alloys together with their corrosion behavior, zinc and its alloys, along with their corrosion behavior, zirconium, its alloys and their corrosion behavior, tin and tin plate with their applications in atmospheric corrosion are discussed. The final part of the chapter concerns refractories and ceramics and polymeric materials and their application in various corrosive media. 

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