Nitrogen in steel

Nitrogen in steel, insufficient aluminum to take up nitrogen (Al N2) strain-aging is aging intensified by cold working. 

Hanin, M., Villeneuve, D. Determination of oxygen and nitrogen in steel by gas chromatography after reductive fusion in an inert gas. Chim. Anal. 48, 442 (1966). 

Hanin, M. Determination of nitrogen in steel after reduction melting under argon and gas chromatography. Chim. Anal. 53, 296 (1971). 

Inhibiting nitrogen taken up by aluminum as Al N2 in fully killed and fine grain steels (nitrogen in steel stabilizes iron carbides.)... 

A different case is the interstitial solid solution, for instance of carbon or nitrogen in steel. Here a large difference in the radii is required because it enables the dissolved atoms to sit in an interstitial position. 

Pickering, F.B. (1998). Some beneficial effects of nitrogen in steel. High Nitrogen Steels 1988 Conference proceedings. The Institute of Metals, London, Brookfield, 1989, p>p.lO-... 

Ekl] Eklund, L., The Solubility of Nitrogen in Steel (in Swedish), Jernkontorets Ann., 123, 545-556 (1939) (Phase Diagram, Phase Relations, Experimental, 13)... 

The complexity of the apparatus needed for ion implantation makes this method of case hardening of limited application. Further, the case depth is considerably lower than that produced by carburizing or nitriding. The depth of implantation of nitrogen in a steel is about 0.00006 cm (19), ie, so thin that it is difficult to measure the hardness profile by conventional microhardness measurements. 

Austenitic Stainless Steels. These steels, based on iron—chromium—nickel alloys, are not hardenable by heat treatment and are predominandy austenitic. They include Types 301, 302, 302B, 303, 304, 304L, 305, 308, 309, 310, 314, 316, 316L, 317, 321, and 347. The L refers to 0.03% carbon max, which is readily available. In some austenitic stainless steels, all or part of the nickel is replaced by manganese and nitrogen in proper amounts, as in one proprietary steel and Types 201 and 202 (see Table 4). 

In North America, calcium cyanamide is no longer used as fertiliser, but it has limited use in special agricultural appHcations for defoHants, fungicides, herbicides, and as a weed killer. The primary industrial use is as a chemical intermediate for the manufacture of calcium cyanide, hydrogen cyanamide solution, and dicyandiamide. Calcium cyanamide is also used to add nitrogen to steel. 

In 110-kV high-voltage grids, gas pressure cables (external and internal gas pressure cables) are mainly laid in steel conduit. In service, the steel pipe is filled with nitrogen at a gas pressure of 15 to 16 bar. Figure 14-1 shows the cross-section of such an external gas pressure cable. 

The gases from the reactor are then cooled and subjected to a caustic wash to remove unreacted hydrogen chloride. This is then followed by a methanol wash to remove water introduced during the caustic wash. A final purification to remove aldehydes and ethylidene dichloride, formed during side reactions, is then carried out by low-temperature fractionation. The resulting pure vinyl chloride is then stored under nitrogen in a stainless steel tank. 

All subsequent green coke operations were made in a second coker, which was fashioned from steel pipe approximately 18 cm in diameter and 25 cm in length. A metal plate was welded to one end and a metal collar was welded to the other end such that a steel lid could be bolted to the system. Typically, about 250 to 500 g of pitch were sealed imder nitrogen in the coker reactor and the system placed in a large temperature-programmable furnace. The heat treatment process was as follows. The temperature was raised 5°C/min to 350 °C and then l°C/min to 425°C and the temperature held at 425°C for 90 minutes. Finally the temperature was raised further at 3°C/min to between 500 and 600°C, and held there for 3 hours. The coker was cooled to room temperature and the material recovered to determine green coke yield. 

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. ...

It is claimed that since S, Ca and A1 will be present as precipitates they would not in general be detected as grain boundary segregants and their ineffectiveness is indicated by the brackets in equation 8.10. Lea and Hondros do not consider the possible roles of carbon or nitrogen in the cracking of their steels, but from the data obtained phosphorous had the most deleterious effects. 

---