High-strength stainless steel

R.D. Moser, P.M. Singh, L.F. Kahn, K.E. Kurtis, Chloride-induced corrosion resistance of high-strength stainless steels in simulated alkaline and carbonated concrete pore solutions, Corros. Sci. 57 (2012) (2012) 241-253. 

The cladding and wrapper tubes are made of high-strength stainless steels that can endure the high-temperature and fast-neutron—irradiation conditions. 

Absorption trains of early ammonia oxidation processes to nitric acid were constructed of chemical stoneware or acid-proof brick, which restricted acid production to near ambient atmospheric pressure because of the low strength of the structural materials. The discovery that Duriron (silicon-iron) or high chrome stainless steels could tolerate these corrosive conditions well allowed the adoption of pressure absorption. This measure markedly decreased the size of the absorbers required and reduced nitrogen oxide stack losses. Pressure operation was easiest to achieve by compression of the feed gases at the front end of the process. In this way improved acid production is obtained at comparable capital costs per unit of product by operation at atmospheric pressure. 

Some metals, when stressed, crack on exposure to a variety of corrosive aqueous solutions with no evidence that the damaging solutions need be specific. For example, a stressed high-strength carbon steel or a martensitic stainless steel... 

The effect of pure acids on stainless steels depends on whether the acid is reducing or oxidizing. If the acid has low oxidizing strength, the stainless will corrode rapidly. If, however, the oxidizing strength of the acid is sufficiently high, the stainless steels will resist corrosion. 

The chief industrial attribute of the cobalt-base alloys is their resistance to wear. They hold a unique position in that they are also corrosion-resistant (when the carbon content is low), and maintain their strengths and wear resistance at high temperatures, by virtue of reasonable microstructural stability (relative to, say, the austenitic manganese steels, the tool steels, and the high-silicon stainless steels). 

Figure 2.8 3-D atom probe picture of a high alloy stainless steel containing Fe, Cr, Ni, Ti, Al, Cu and Mo. For visibility only the atoms of copper (light) and aluminum (dark) are shown. These atoms are not evenly distributed but have formed Al-Cu particles, whereby the strength of the alloy is enhanced. (Reprinted with the permission of Dr Mats Hattestrand, Chalmers Institute of Technology, Gothenburg, and AB Sandvik Steel, Sweden.)...

After boronizing, the corrosion rate of boronized low carbon steel AISI 1018 is about 100 times lower than the corrosion rate of unboronized one based on the electrochemical measurement (Suwattananont, 2005). The boronized high strength alloy steel AISI 4340 and austenitic stainless steel AISI 304 have corrosion rate about several times lower than the corrosion rate of imboronized steels. The comparison of the tafel plots between boronized and imboronized AISI 1018 steel is shown in Fig. 8. 

The highly aHoyed austenitic stainless steels are proprietary modifications of the standard AISI 316 stainless steel. These have higher creep—mpture strengths than the standard steels, yet retain the good corrosion resistance and forming characteristics of the standard austenitic stainless steels. Nickel-Base Superalloys. 

The fifth component is the stmcture, a material selected for weak absorption for neutrons, and having adequate strength and resistance to corrosion. In thermal reactors, uranium oxide pellets are held and supported by metal tubes, called the cladding. The cladding is composed of zirconium, in the form of an alloy called Zircaloy. Some early reactors used aluminum fast reactors use stainless steel. Additional hardware is required to hold the bundles of fuel rods within a fuel assembly and to support the assembhes that are inserted and removed from the reactor core. Stainless steel is commonly used for such hardware. If the reactor is operated at high temperature and pressure, a thick-walled steel reactor vessel is needed. 

Drums. Typical selection for the number of dmms used in the various appHcations is two to four for cobbers, one or two for roughers, and two or three for finishers. The inner dmm sheU, usually 3 mm thick, is specified Series 302 or 304 stainless steel. Dmm heads are usually of high tensile strength aluminum alloy or brass. Recessed head bolt constmction having an effective seal is specified. 

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