Nickel-chromium-high molybdenum

Nickel-Chromium-High Molybdenum Alloys Titanium... 

Alloys rich in nickel, chromium, and molybdenum, such as C-22, C-276, and C-2000, offer the broadest range of corrosion inhibition. The high molybdenum content assists in diminishing corrosion by reducing acids, while the high chromium content assists in diminishing corrosion by oxidizing acids. ... 

INMETCO s High Temperature Metals Recovery process reclaims the nickel, chromium, iron, molybdenum and cobalt fi om the secondary wastes indicated above and produces a remelt alloy in cast pig form, weighing 25-30 pounds. The remelt alloy is shipped to most of the stainless steel manufacturers in the United States, as well as certain other international companies, for use as raw material feedstock in the production of more stainless steel. As an ISO 9002 certified facility, INMETCO, a fully permitted facility, is the only High Temperature Metals Recovery facility in North America dedicated to the recovery of nickel, chromium, iron and molybdenum from both hazardous and non-hazardous wastes. 

Manufacturers of nitinol products are known to electropolish the surface of the nitinol wire to produce an oxidized surface layer that contains only titanium and oxygen. This reduces the potential for nickel allergy and toxicity problems. The alloy MP35N used in the CS/SF device is a quaternary of cobalt, nickel, chromium, and molybdenum, and is known to have high strength and corrosion resistance. Additionally, this metal has been found to be biocompatible and MR compatible. These are all desirable properties for an implantable device, but its nickel content should be noted and considered when dealing with patients who are allergic to nickel. 

Due to the high chromium contents, duplex alloys are sensitive to 885 (475°C) embrittlement. This generally limits their usage to 600°F (SIS C) maximum for pressure vessels. Due to the presence of nickel, chromium, and molybdenum they are also susceptible to the formation of affect mechanical properties and corrosion resistance due to alloy depletion. The temperature range of 1100°F (593 C)-1600°F (882°C) and most rapidly at about 1450°F (788°C). The deleterious effects of phase formation are not obvious at the elevated temperature but can become a factor at room temperature. The formation of a phase in these alloys is sufficiently rapid to have an effect on properties due to slow cooling (air) after anneal. A measurable effect as a result of exposure in this temperature range due to welding has been demonstrated. 

Residual stresses occur from welding and other fabrication techniques even at very low stress values. Unfortunately, stress relief of equipment is not usually a reliable or practical solution. Careful design of equipment can eliminate crevices or splash zones in which chlorides can concentrate. The use of high-nickel stainless steel alloy 825 (40% nickel, 21% chromium, 3% molybdenum and 2% copper) or the ferritic/austenitic steels would solve this problem. 

Stainless steels, which contain high percentages of alloying elements, e.g. 18% chromium, 8% nickel and 3% molybdenum. Steels of this type are practically non-corrodible in appropriate circumstances. 

Most modern industrial materials are designed to be passive i.e., covered by an adherent, chemically inert, and pore-free oxide that is highly insoluble in aqueous solutions and hence dissolves at an extremely slow rate. Examples would be modern stainless steels, nickel-chromium-molybdenum, and titanium alloys. The concept of passivity is often defined by reference to the polarization curve for metals and alloys in aggressive acidic solutions, Fig. 22. This curve defines the potential regions within which the alloy would be expected to corrode actively or passively. 

NOTE Other standard specifications exist for iow carbon, manganese, molybdenum, columbium and low carbon, nickel, chromium, molybdenum, and copper high-yield strength steels. 

Chemical leach tests on the bulk settled dust samples showed that the dusts are quite chemically reactive. Leach solutions have high alkali-nities, due to the rapid partial dissolution of calcium hydroxide from concrete particles. Indoor dust samples produced higher pH levels (11.8-12.4) and alkalinities (—600 mg CaCOa) than outdoor dusts (pH 8.2-10.4 alkalinity —30mgL CaCOa), indicating that outdoor dust samples had reacted with rainfall or other water prior to collection. Thurston et al (2002) found that the leachate pH of the dusts decreased with decreasing particle size. Some metals or metalloids in the dusts (aluminum, chromium, antimony, molybdenum, barium, copper, zinc, cobalt, nickel) are readily leached by deionized water many of these form oxyanion species or carbonate complexes that are most mobile at the alkaline pH s generated by the leachates. 

Stainless steel welders are at high risk for developing asthma. The fumes emitted into the welders breathing zones contain hexavalent chromium, iron, nickel, manganese, titanium, molybdenum, copper, and chromium, as well as silica, calcium carbonate, volatile organic compounds from fluxes and fumes from burnt paints. I64 68 ... 

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