Stainless steel components

Carbon steel contacting mill coolant had suffered general corrosion. Stainless steel components were unaffected. Although many factors contributed to wastage in these systems, deposits played an important role (Fig. 4.27A and B). Corrosion exactly mirrored deposition patterns. 

When stress-relief-annealing 300 series stainless steel components, care must be taken to avoid slow cooling through the sensitization range (see Weld Decay in this chapter). 

Galvanic corrosion may also occur by transport of relatively noble metals, either as particulate or as ions, to the surface of an active metal. For example, ions of copper, perhaps resulting from corrosion or erosion-corrosion at an upstream site, may be carried by cooling water to the surfaces of aluminum, steel, or even stainless steel components. If the ions are reduced and deposit on the component surfaces, localized galvanic corrosion may result. 

Note also that a galvanic couple can be established between passive regions and active regions of the same stainless steel component. For... 

There is one major pitfall which must be avoided in using stainless-steel components joined by welding it is known as weld decay. It is sometimes found that the heat-affected zone - the metal next to the weld which got hot but did not melt - corrodes badly. 

Barone, G., Stidsen, G., and Lavrich, D., Improving the performance of analytical instrumentation using passivated stainless steel components, Am. Lab. News, 31(19), 26, 1999. 

Common HPLC solvents with adequate purity are commercially available. Halogenated solvents may contain traces of acidic impurities that can react with stainless steel components of the HPLC system. Mixtures of halogenated solvents with water should not be stored for long periods, as they are likely to decompose. Mixtures of halogenated solvents with various ethers, e.g., diethyl ether, react to form products that are particularly corrosive to stainless steel. Halogenated solvents such as methylene chloride react with other organic solvents such as acetonitrile and, on standing, form crystalline products. 

Most HPLC equipment currently available has a high tolerance to most mobile-phase conditions that can be contemplated for use in RPC applications with peptides. If it is intended to use mobile phases containing halide salts in RPC separations of peptides with standard HPLC equipment made from type 316 stainless steel, it is essential that the equipment is properly flushed with neat water when not in operation to avoid corrosion by the residual halide ions, especially at low pH. Otherwise, the use of the less popular biocompatible metal-free HPLC equipment, marketed by several manufacturers, avoids potential problems of equipment malfunction due to corrosion of the stainless steel or the contamination of peptide samples by low levels of leached metal ions. With such metal-free HPLC equipment, titanium, glass, or perfluoro-polymeric components have been used to replace any wettable stainless steel components. 

The cooling tower, which is an efficient air scrubber can easily become a catchall for contaminants resulting from the location of the tower or from the industrial process. In arid areas, ingress of sand contributes to fouling, which reduces efficiency and contributes to biofilm and under-deposit corrosion. In coastal areas, sand laden with chlorides can cause corrosion of stainless steel components and impair chemical corrosion inhibitor performance. Heavy industries, such as steel or aluminum manufacture, produce severely contaminated cooling water resulting from direct contact with metal slags and lubricants. 

Dispensers for gasoline and diesel fuel typically use steel, cast iron, aluminum, brass, bronze, and sometimes stainless steel components. Of these, only the steel, cast iron, and stainless steel components are compatible with methanol. The other parts will need to be nickel-plated or substitutes made from a compatible metal. Gasboy, Tokheim, and Wayne-Dresser have produced methanol-compatible versions of their gasoline dispensers. 

All valves contain rubber components (gaskets, tank seals, seats, or sleeves) and at least one stainless steel part (spring). Both are vital to valve functionality. Some types of valves contain more plastic or stainless steel components than others. Drawings of individual subcomponents of the valve should be on hand for reference to the incoming components. Periodic checking of the rubber or other components may be needed to ensure that the supplier has not changed any compositions or processing procedures. 

This is generally believed to result from the substitution of chloride ions into the surface oxide lattice with subsequent breakdown of the passification of the underlying alloy. The elimination of inorganic chloride contamination from stainless steel components used in nuclear applications has been a goal of designers for many years. 

External parts such as the valve body, bonnet and cap should be cleaned by immersion in a bath such as hot Oakite solution or equivalent. These external parts may be cleaned by wire brushing, provided the brushes do not damage or contaminate the base metals. Only clean stainless steel brushes should be used on stainless steel components. For the ultimate best results, these parts could also be pickled and passivated. 

Conclusions. Examination of the failed pipe clamp revealed the presence of brittle fracture surfaces as well as an extensive array of branched transgranular cracks. The identification of the clamp material indicated it was a forged 304 stainless steel component... 

The fuel pins are transferred into slotted cans and the redundant graphite sleeves and additional stainless steel components are stored in drums as Intermediate Level Waste (ILW). This not only converts the fuel into a form suitable for reprocessing but also results in a 3 or 4 fold increase in storage density. 

To improve the corrosion resistance of the stainless steel components, particularly in the weld-affected areas, it is a common practice to passivate the product contact surfaces of installed piping and equipment by circulating a solution of strong oxidant such as nitric or citric acid, or a chelating agent. Passivation removes free iron from the metal surface and creates a thin protective layer of chromium oxide. It is not uncommon to repeat the passivation treatment periodically (every few years) to restore the passive layer. 

Austenitic stainless steels like 31 OS, 316, or 316L are typically used for the construction of cathode and anode current collectors and bipolar separator plates. Corrosion of these steel components is a major lifetime-limiting factor in MCFC. The corrosion behavior of stainless steel components in molten carbonate conditions has been studied extensively during the past decade. Research is being aimed at increasing the corrosion resistance of these components by altering the alloy composition or by surface modification techniques. ... 

If your experimental design performs to your satisfaction, you can then upgrade to more durable components. High quality stainless steel components should be used in every system intended for any length of service. Other materials can be substituted, but they must stand up to the condi-... 

Chromatography of proteins often requires the use of high-salt mobile phase, which is corrosive to stainless steel.7 HPLC systems and columns for this application often use titanium or PEEK to substitute for stainless steel components in their fluidics. Other systems have built-in column switching for isolating active components using affinity/IEC or other tandem two-dimensional chromatography (Figure 4.13d). 

Since 1973 [3] and 1975 in Dresden 2 [4], on line measurements of redox potential have been performed in the BWRs (Boiling Water Reactors) primary coolant in order to verify the IGSCC (Intergranular Stress Corrosion Craking) susceptibility of austenitic stainless steel components. Such measurements turned out to be fundamental for estimating the effect of hydrogen addition as a remedy for IGSCC [5-6]. 

Pd-40Cu was approximately matched by using Monel in the module components in direct contact with the membrane (the membrane support), whereas in the other case 304 stainless steel was used for the membrane support As shown in Table 5.1, the coefficient of thermal expansion of 304 stainless steel is substantially greater than the coefficient of thermal expansion of Pd-40Cu. Failure occurred after only a few cycles in the case of the 304 stainless steel components, whereas the Monel components demonstrated much improved durability. 

Unnecessary costs are incurred for repair and replacement because of improper selection of materials such as the stainless steel components for environments where they fail to perform satisfactorily. Concrete spalling because of the corrosion of reinforcing steel may be a consequence of a lack of awareness of the reasoning used in construction codes of practice. Thus the costs incurred in the case of premature degradation of public buildings by corrosion must be met by the community and financed by third parties for the repairs. 

Yearly inspection or twice in a year inspection of stainless steel components especially load bearing components is desirable. Where staining or corrosion is found, corrosion products may be removed and the loss of cross section and integrity assessed. Load bearing or other safely components should be tested for SCC. When necessary, components should be more corrosion-resistant stainless steel parts. 

From 1983 until its shutdown in 1994 PFR experienced cracking in type 321 stainless steel components in its secondary circuits, some cracks leading to sodium leaks. As a result a substantial repair and inspection programme was required in the final seven years of PFR operation. Although the two earliest leaks were in pipework (in 1983 and 1986) the majority were in steam generator vessels. The pipework leaks were only retrospectively identified as being caused by the same mechanism. 

An alumina adhesive layer is placed on both ends of catalytic bed, in order to provide a radial flow for gases coming from the mixing chamber and the membrane tube is inserted inside the catalytic bed. Furthermore, in order to allow simultaneously the sweep gas inlet and the permeate outlet, a stainless steel component (Fig. 6.5) is inserted at the top of the reactor. 

One of the more difficult features to quantify in detail is welded joints and assemblies. A common way to indicate the standard of finish on welded stainless steel components is by the provision of small examples. It is comparatively easy to achieve any required finish on a small component that is fully accessible and manoeuvrable, but quite a different matter to attain the same quality over every minute region of a large and complex fabrication. To remove subjective judgement as far as practical from the inspector s task it may be useful to have examples of a slightly lower grade of finish, and/or of what is not acceptable at any point of the final equipment, for comparison. 

Another important development in forging technology is the use of austenitic stainless steel components for fast breeder reactors (FBRs). Components of the reactor vessel for Monju, the prototype FBR in Japan, were manufactured using type 304 stainless steel. Significant advances in production technologies were made to fabricate the austenitic steel... 

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