Nickel alloys brass

Being very clean and pure minimizes the materials compatibility concerns for LNG. However, LNG presents a new materials compatibility concern operation at cryogenic temperatures.3 For LNG fuel tanks, stainless steel is the preferred material and instances of materials compatibility problems are rare. Aluminum also has been used as a tank material without materials compatibility problems. Carbon steels are not used since their performance at low temperatures is questionable, i.e., they become susceptible to brittle fractures. While tanks are usually made from stainless steel or aluminum, LNG fittings may use some nickel alloys, brass, and copper, in addition to stainless steel and aluminum. 

Table 14. Properties of Copper-Nickel Alloys and Leaded Nickel Bronze and Brass...

Metal Fabrics or Screens These are available in several types of weave in nickel, copper, brass, bronze, aluminum, steel, stainless steel. Monel, and other alloys. In the plain weave, 400 mesh is the closest... 

It is not possible to plate rhodium directly on to reactive metals of the type mentioned above, in view of the acid nature of the electrolyte, but copper and its alloys, e.g. nickel-silver, brass, phosphor-bronze, beryllium-copper, which are of special importance in the electrical contact field, may be plated directly. Even in this case, however, an undercoat is generally desirable. 

A similar method of test was used at the International Nickel Company s Corrosion Laboratory at North Carolina. The specimen discs are mounted on insulated vertical spindles and submerged in sea-water, which is supplied continuously to the tank in which the specimens are immersed. The maximum peripheral speed of the spinning disc is about 760cms , and the characteristic pattern of attack is shown in Fig. 19.3a. Studies of variation of depth of attack with velocity indicate that at low velocities (up to about 450 cm s ) alloys such as Admiralty brass, Cu-lONi and cupro-nickel alloys containing iron maintain their protective film with a consequent small and similar depth of attack for the diflferent alloys. At higher velocities the rate increases due to breakdown of the film. 

A form of corrosion in which of one or more elemental constituents of an alloy is leached, often leaving a porous structure. Examples are dezincification of brass and denickelization of nickel alloys. 

Metals that are generally stiffer than brass include steels, nickel alloys, molybdennm alloys, and tungsten alloys. All but steel are generally expensive. Molybdennm and tnngsten alloys have high melting points. 

The nickel silvers generally are classified as brasses. Cupronickels fall more into basic copper-nickel alloys. Possible minor ingredients are manganese, iron, and zinc. These alloys can be used for severe drawing, spinning, and stamping operations because Ihey do not harden readily. They also are extensively used for condenser lubes and plates, heat exchangers, and other process equipment. 

Copper alloys (brass, bronze, etc.) for very shock-sensitive perchlorate salts Aluminum (dissolves at room temperature) High nickel alloys (dissolves), others Cotton Wood... 

Appendix A contains a materials selection guide for aerated freshwater systems. As indicated in Note 27 of Appendix A, in freshwater systems, admiralty brass should be limited to a maximum pH value of 7.2 from ammonia and copper-nickel alloys and should not be used in waters containing more sulfides than 0.007 mg/L The materials selection guide is also satisfactory for seawater, although pump cases and impellers should be a suitable duplex stainless steel or nickel-aluminum-bronze (properly heat treated). Neoprene-lined water boxes should be considered. For piping, fiber-reinforced plastic (up to 150 psi [1,035 kPa] operating pressure) and neoprene-lined steel should also be considered. Titanium and high-molybdenum SS tubes should be considered where low maintenance is required or the cost can be justified by life expectancy. 

The choice between brass and copper-nickel alloys is contingent on ammonia content and temperature of process side. Brass should not be used when the pH due to ammonia exceeds 7.2. Copper-nickel alloys should not be used If the sulfides in the water exceed 0.007 mg/L. 

Copper and Copper Alloys Seamless copper, bronze, brass, copper-nickel-alloy and copper-silicon-alloy pipe and tubing are produced by extrusion. Tubing is available in outside-diameter sizes from Vie to 16 in and in a range of wall thicknesses varying from 0.005 in for the smallest tubing to 0.75 in for the 16-in size. Tubing is usually specified by outside diameter and wall thickness. 

Copper-Nickel Alloy (0.5 Fe) 90/10 Copper-Nickel Alloy (1.5 Fe) Aluminum Brass Admiralty Copper... 

Selective leaching applies to the situation where one element of an alloy is removed preferentially to another metallic constituent. The most common example of this phenomenon is the so-called dezincification of brass (see Section 10.2.1), but it may also occur through the selective removal of nickel from cupro nickel alloys and aluminium from aluminium bronze. 

For 1-1/2-inch and smaller check valves, specify 250-pound SWP brass, screwed, horizontal-piston type, nickel-alloy seat and disc. 

This situation can be observed, for example, in the case of aluminium brass and of the 90 10 Cu Ni and 70 30 Cu Ni copper nickel alloys interacting with artificial sea water... 

The curves relate to the behaviour of aluminium brass and of the 90 10 and 70 30 copper nickel alloys in artificial sea water at pH 8.2 and a temperature of 40 °C. The surface area of the electrodes was about 33.7 cm, while the sea water flow rate was 1.0 ms. The geometry of the three electrolytic cells was the same. 

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