Corrosion resistance listed

The thermal insulation value and other properties of the brick and protective membrane layer between the brick and the process fluid it contains can be determined from property values (such as corrosion resistivity) listed in catalogs supphed by the brick manufacturers or relevant engineering standards. See Some Commonly Used Specifications, Codes, Standards, and Texts. 

Note from the Sec. 28 editors to the readers of this handbook Historically, previous editions of Perrys Chemical Engineers Handbook carried an extensive series of so-called corrosion resistance tables [listing recommended materials of construciion (MOC) versus various corrosive environments]. This practice goes back, at least, to the Materials of Construction Sec. 18, 1941, 2d ed. Unfortunately, if valid at all, these data are only usable as indicators of what will not work for. sure, the.se listings should not be used as recommendations of what materials are con o.sion resistant. The section editors have elected to no longer include these data tabulations. 

Stainless steels contain 11% or more chromium. Table 5.1 lists common commercial grades and compositions of stainless steels. It is chromium that imparts the stainless character to steel. Oxygen combines with chromium and iron to form a highly adherent and protective oxide film. If the film is ruptured in certain oxidizing environments, it rapidly heals with no substantial corrosion. This film does not readily form until at least 11% chromium is dissolved in the alloy. Below 11% chromium, corrosion resistance to oxygenated water is almost the same as in unalloyed iron. 

Tables 2.3 through 2.5 give general corrosion-resistance ratings of different materials. Table 2.3 lists various metals and Table 2.4 gives ratings for various nonmetals. Table 2.5 gives typical corrosion rates of steel and zinc panels exposed to the atmosphere in various locations about the U.S. Figure 2.1 also illustrates relative corrosion rates of steel and zinc in major areas of the world.

In many applications tantalum can be substituted for platinum and gold, and there are some environments in which tantalum is more corrosion resistant than platinum. Table 3.37 lists the main chemicals for which tantalum is not a suitable substitute for platinum and, conversely, those for wliich tantalum is better than platinum. Tantalum is rapidly embrittled by nascent hydrogen even at room temperature. Therefore, it is very important to avoid the formation of galvanic couples between tantalum and other metals. 

Many of the uses listed in Table A are a matter of everyday observation. In nddition we may nole that the electrical conductivity of pure A1 is 63.5% of the omduedvity of an equal whune of pure Cu when the lower density of A1 is considered its conductiviQr is 2.1 times that of Cu on a wt for wt. basis. This, coupled with its corrosion resistance and ready workability makes it an ideal metal for power lines and. indeed, more than 90% of all overhead electrical transmission lines in the USA are A1 alloy. 

Material Properties. Materials possess various mechanical and chemical properties, and, therefore, it is possible to select materials appropriate for severe corrosion conditions. For example, if the equipment is under cyclic loading, a material with high fatigue strength is desired. Similarly, it is desirable to have corrosion-resistant materials for the corrosive environments. There are several sources for obtaining information on materials properties. Some are listed in Table 4-173. 

Corrosion resistance data lists on specific materials offered for sale. However the engineer must also consider mechanical and physical properties and, last but not least, the cost of the material, its fabrication and protection. Thus reference must be made to books, journals and data that provide this information. 

As will have become apparent, nickel and corrosion-resistant nickel alloys have wide ranges of application, particularly in industries where strongly acidic, strongly alkaline or strongly saline environments are encountered. Table 4.29 lists some of the more important applications in those industries where these conditions most frequently arise, i.e. in the chemical, petrochemical, oil and gas, nuclear and conventional power generating, textile, paper, marine, desalination and food processing industries. The list is by no means exhaustive and there are many other applications of a similar nature in these and other industries. The table should, nevertheless, serve... 

Plants producing and handling halogens and halogen compounds Tantalum finds extensive use in the production and handling of hydrochloric and hydrobromic acid, chlorine and bromine and many of their derivatives. Absorbers, coolers and heaters which show considerable advantages in terms of heat-flux capabilities and corrosion resistance have been used on hydrochloric acid duties for over 40 years and condensers have been used in bromine plants for at least the same period. Typical applications of tantalum in the bromine and chlorine industries are listed in Table 5.27 . 

Methods of applying paint today are numerous and it is impossible to list and describe them in detail in a section of this size. Where corrosion resistance of the finished article is a major consideration, it is possible to apply controls to ensure that maximum corrosion protection is obtained from the selected application process. 

Pressure vessels and appurtenances should be constructed of stainless steel or other corrosion-resistant materials. Ideally, these steam generators should receive hot demineralized FW to minimize chemical treatment requirements. Alternatively, where a main boiler plant is installed, 100% steam condensate provides a good source of FW. In practice, it is very difficult to accurately control the correct amount of chemical feed. Chemicals are typically restricted to potable grade, deposit control agents such as polyacrylates, and other materials listed under the Code of Federal Regulations, CFR 21 173.310, or National Sanitary Foundation (NSF International) approval system. These boilers may be electrically heated or gas-fired. 

Other CVD Corrosion-Resistance Applications. The following is a listing of typical applications where CVD is used either in production or experimentally for corrosion protection. 

Some of the more important properties of materials that are used for the construction of embankments or fills include gradation, unit weight, specific gravity, moisture-density characteristics, shear strength, compressibility, bearing capacity, permeability, and corrosion resistance. Table 4.21 provides a list of the standard test methods usually used to assess the suitability of conventional earthen fill materials for use in embankment or fill construction. 

The physical properties of lead and several of its compounds are listed in Table 3-2. Lead readily tarnishes in the atmosphere but is one of the most stable fabricated metals because of its corrosive resistance to air, water, and soil (Howe 1981). A waste that contains lead or lead compounds may (or may not) be characterized a hazardous waste following testing by the Toxicity Characteristic Leaching Procedure (TCLP) as prescribed by the Resource Conservation and Recovery Act (RCRA) regulations. 

In general, the requirements for plate and plate materials listed in Table 5.1 can be classified as electrical properties, corrosion resistance, mechanical properties, gas permeability or soundness, weight, and cost. Although the output power of a stack is determined by many factors, one simple interpretation of the 2010 DoE cost target is US 2 per plate, which has often been quoted as a convenient estimation [8]. In addition to the cost requirements, the other requirements are all linked either directly or indirectly to the functions of the plate mentioned earlier. 

The equipment shall be identified with item and serial numbers. Material shipped separately shall be identified with securely affixed, corrosion resistant metal tags indicating the item and serial number of the equipment for which it is intended. In addition, crated equipment shall be shipped with duplicate packing lists, one inside and one on the outside of the shipping container. 

Nickel and Nickel Alloys A wide range of ferrous and nonfer-rous nickel and nickel-bearing alloys are available. They are usually selected because of their improved resistance to chemical attack or their superior resistance to the effects of high temperature. In general terms their cost and corrosion resistance are somewhat a function of their nickel content. The 300 Series stainless steels are the most generally used. Some other frequently used alloys are listed in Table 10-39 together with their nominm compositions. For metallurgical and corrosion resistance data, see Sec. 25. 

The above metals are used in many industrial processes. Cadmium, for instance, is plated onto fabricated metal parts to provide corrosion resistance, lubricity and other desirable properties it is used in rechargeable batteries, television and fluorescent light phosphors, inorganic coloring agents for paint, plastic and printing ink, and as a catalyst. Applications of the metals listed above are detailed in Table 2-1, categorized by Standard Industrial Classification (SIC) codes. These industries are discussed further in Section 4.0. 

Physical Properties. An overview of the metallurgy (qv) and solid-state physics of the rare earths is available (6). The rare earths form alloys with most metals. They can be present interstitially, in solid solutions, or as intermetallic compounds in a second phase. Alloying with other elements can make the rare earths either pyrophoric or corrosion resistant. It is extremely important, when determining physical constants, that the materials are very pure and well characterized. All impurity levels in the sample should be known. Some properties of the lanthanides are listed in Table 3. 

Electroplated materials are generally employed for a specific property or function. There is, of course, some overlap for example, decorative use certainly requires some degree of corrosion resistance. The various usages and the principal plating metals employed are as listed. There are also smaller amounts of other metals and alloys used for specific applications. 

The CC—13- and (3-alloys are used where higher strengths are required, such as in shafts, oil and gas wells, and medical implants. Again, Pd and Ru variations of the basic alloys are available where improved corrosion resistance is needed. Several of the listed P-alloys were developed for implants. These alloys were designed to be free of aluminum and vanadium, which have created some concern related to potential toxicity when used in implants (50). 

Based on factors such as cast, mechanical properties, physical properties, ease of fabrication (design) and the corrosion resistance data available in the literature the choice of materials can lead to a short list of two or three materials. At this stage it is prudent that the engineer design prototype laboratory scale model equipment from the short-list of selected metals or alloys, and determine the corrosion rates in the environment of interest. These accelerated tests will enable the engineer to select the best candidate material, making proper allowance for the corrosion of the metal or alloy over the lifetime of the equipment. 

It is virtually an impossible task to list materials suitable for successful operation in every conceivable set of environmental conditions. The choice of material for use in a given environment depends upon the corrosion resistance of the material as the primary factor. The cost of the material is also an important factor in the ultimate selection of the material. 

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