Chromium-molybdenum alloys

Table 2.24 Breakdown potentials (mV) for 316 stainless steel, titanium and cobalt-chromium-molybdenum alloy in oxygen-free 0.17 m NaCl solution at 37°C using a silver/ silver chloride reference electrode.

Table 2.25 Breakdown potentials for 316S12 stainless steel (cold worked), high nitrogen stainless steel (cold worked), titanium-6Al-4V and cast-cobalt-chromium-molybdenum alloy in continuously aerated aqueous acidified chloride solution 0.23 m [C1 ] pH 1.5 at 25°C. ...

Nickel-chromium alloys, 77 100-101 dental applications, 8 308, 310 Nickel-chromium-iron alloys, 73 519, 522 Nickel-chromium-molybdenum alloy C, in galvanic series, 7 805t... 

Cobalt-chromium alloy (see Chromium and chromium compounds) Cobalt-chromium-molybdenum alloys (see Cobalt and cobalt compounds) Cobalt metal powder (see Cobalt and eobalt compounds)... 

Normally a steel is considered in tins category if it has a yield strength of 160,000 psi or more. The first of these steels to be produced was a chromium-molybdenum alloy steel, shortly followed by a stronger chromium-nickel-moly bdenum grade. 

Elevated levels of chromium in blood, serum, urine, and other tissues and organs have been observed in patients with cobalt-chromium knee and hip arthroplasts (Michel et al. 1987 Sunderman et al. 1989). Whether corrosion or wear of the implant can release chromium (or other metal components) into the systemic circulation depends on the nature of the device. In one study, the mean postoperative blood and urine levels of chromium of nine patients with total hip replacements made from a cast cobalt-chromium-molybdenum alloy were 3.9 and 6.2 pg/F, respectively, compared with preoperative blood and urine levels of 1.4 and 0.4 pg/F, respectively. High blood and urinary levels of chromium persisted when measured at intervals over a year or more after surgery. These data suggest significant wear or corrosion... 

Explosively clad metals, of which Deta-Clad4 is an example, are used mostly for small items such as tube sheets and heads for small heat exchangers or vessels. It is usually not economical for large surfaces or complex shapes. Nickel-chromium-molybdenum alloys and some other expensive metals can be applied to carbon steel by explosive bonding. 

Anodic Polarization of Iron-Chromium-Molybdenum Alloys... 

Table 7-28. Carbon-Molybdenum and Chromium-Molybdenum Alloy Steel Pipe for...

Nickel-chromium-molybdenum alloys are used in reactor vessels in the production of acetic acid. These alloys are cost-effective compared to Ni-Cr stainless steels and have good resistance to oxidizing corrosive media Ni-Mo alloys have good resistance to reducing media. Molybdenum together with the chromium stabilizes the passive film in the presence of chlorides and is particularly effective in increasing resistance to pitting and crevice corrosion. 

Most steel wheelchairs are made of mild steel (1040 or 1060) or chromium-molybdenum alloy (4130 or 4140) seamless tubing commonly called chro-moly. Mild steel is very inexpensive and easy to work with. It is wildly available, and performs well for many appUcations. However, it has a low strength to weight ratio compared to other materials. Chro-moly is widely used because of its weldability, ease of fabrication, mild hardenabihty, and high fatigueabihty. Commonly wheelchairs are made of tubing 0.028 to 0.035 in. in wall thickness but diameters vary depending on the expected loads between 0.25 and 1.25 in. 

Stainless steel, which is typically used for bone plates, screws, and nails, is particularly susceptible to corrosion, although its chromium and molybdenum content (about 17% and 3%. respectively) helps to make it more resistant. Cobalt-chromium-molybdenum alloys exhibit excellent durability and strength, making them apposite for artificial joints, although their coefficients of friction make them unsuitable for load-bearing surfaces. 

Put] Putman, J.W., Grant, N.J., Bloom, D.S., a Phase in Chromium-Molybdenum Alloys with Iron or Nickel in Symposium on the Nature, Occurrence, and Effects of Sigma Phase , American Society for Testing Materials, Philadelphia, PA, 61-68 (1950) (Morphology, Phase Diagram, Experimental, 6)... 

Bae] Baen, S.R., Duwez, P, Constitution of Iron-Chromium-Molybdenum Alloys at 1200F , Trans. Amer. Inst. Min. Met. Eng., 191, 331-335 (1951) (Crys. Straeture, Morphology, Phase Diagram, Experimental, 13)... 

Figure 3.22 shows the peak 3p3/2 of chromium measured on an iron-chromium-molybdenum alloy surface covered by thin oxide film [5]. The background noise has been subtracted, and the double peak of chromium has been deconvoluted into two peaks that correspond to oxidized and metallic chromium. Even though this procedure... 

Figure 3.22 Deconvolution of XPS peak Cr ipy2 measured on a passive film that formed on an iron-chromium-molybdenum alloy (adapted from ref. [5]).

Figure 6.5 illustrates how the presence of an oxidizing agent affects the observed polarization behavior of a metal. It shows the polarization curves of a nickel-chromium-molybdenum alloy in sulfuric acid, with and without ferric sulfate added... 

The need to develop new materials for artificial hip joints is driven, in part, by the local and systemic biological consequences of wear debris arising from the currently used materials. As a result, most studies of artificial joint materials, such as alumina, cobalt-chromium-molybdenum alloys (CoCrMo), and ultrahigh molecular weight polyethylene (UHMWPE), concentrate on wear analyses, most reliably carried out with a hip-joint simulator and involving wear-... 

Nickel-copper and nickel-chromium-molybdenum alloys are the nickel-base alloys that are t5fpically used in seawater. The nickel-copper alloys have good corrosion resistance in high velocity seawater, but do exhibit localized corrosion in quiescent seawater [79]. Alloy 625, a nickel-chromium-molybdenum alloy, is susceptible to crevice corrosion in both quiescent and flow conditions [97-700]. Other nickel-chromium-molybdenum alloys, such as Alloys C-276, C-22, 59 and 686 have increased seawater crevice corrosion resistance as compared to Alloy 625 [97,98],... 

Klein, P. A., Ferrara, R. J., and Kain, R. M., Crevice Corrosion of Nickel-Chromium-Molybdenum Alloys in Natural and Chlorinated Seawater, Paper 112, CORROSION/89, NACE International, Houston, TX, 1989. 

Metals are used in the cardiovascular area including heart valves, heart pacemaker leads, and heart pacemaker cases. These metals include titanium, titanium aUojrs, cobalt-chromium alloys, and cobalt-nickel alloys. Metals used for aneurism clips include cobalt-chromium-molybdenum alloys, cobalt-nickel-chromium-molybdenum allojfs, and, previously, stainless steels were used. Metal seeds are used for fractionated hyperthermia treatment of prostate disease, and corrosion analysis showed the alloy, PdCo may be suitable for the seed implants [52],... 

Kilner, T., The Relationship of Microstructure to the Mechanical Properties of a Cobalt-Chromium-Molybdenum Alloy Used for Prosthetic Devices," Ph.D. thesis. University of Toronto, 1984. 

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