Low carbon

Their boiling points increase with the number of carbon atoms. For molecules of low carbon numbers, the addition of a carbon increases the boiling point about 25°C. Further additions result in a smaller increase. The density increases with the molecular weight 0.626 kg/1 for pentane which has 5 atoms of carbon, 0.791 kg/1 for pentacosane which has 25 carbon atoms, but the density is always much lower than 1. 

Group I. This includes the lower members of the various homologous series (4-5 atoms in a normal chain) that contain oxygen and/or nitrogen in their structures they are soluble iu water because of their low carbon content. If the compound is soluble in both water and ether, it would also be soluble in other solvents so that further solubility tests are generally unnecessary the test with sodium bicarbonate solution should, however, be performed (see Section XI,6). 

Chromium is the most effective addition to improve the resistance of steels to corrosion and oxidation at elevated temperatures, and the chromium—molybdenum steels are an important class of alloys for use in steam (qv) power plants, petroleum (qv) refineries, and chemical-process equipment. The chromium content in these steels varies from 0.5 to 10%. As a group, the low carbon chromium—molybdenum steels have similar creep—mpture strengths, regardless of the chromium content, but corrosion and oxidation resistance increase progressively with chromium content. 

Soft magnetic materials are characterized by high permeabiUty and low coercivity. There are sis principal groups of commercially important soft magnetic materials iron and low carbon steels, iron—siUcon alloys, iron—aluminum and iron—aluminum—silicon alloys, nickel—iron alloys, iron-cobalt alloys, and ferrites. In addition, iron-boron-based amorphous soft magnetic alloys are commercially available. Some have properties similar to the best grades of the permalloys whereas others exhibit core losses substantially below those of the oriented siUcon steels. Table 1 summarizes the properties of some of these materials. 

SiMn = silicomanganese LCFeMn = low carbon ferromanganese LCSiMn = low carbon siUcomanganese FeMnN = nitrided ferromanganese and... 

This product is mainly used within the ferroalloy plant as the reducing agent in a silicothermic process to produce the low carbon grade of refined ferromanganese. 

Refined Ferromanganese. Refined ferromanganese refers to alloys that are not carbon saturated and range from less than 0.10 to 1.50% maximum carbon. Medium carbon grades are used in special grades of steels where in final additions carbon control is important. The low carbon grades are used mainly in the production of certain grades of stainless steels. 

In the past, all grades of refined ferromanganese were made by various modifications of multistep silicon reduction processes. Depending on the carbon content desired in the product, a manganese ore and lime mixture was allowed to react with the silicon in silicomanganese or low carbon silicomanganese in an open, electric-arc furnace. The equilibrium reaction is... 

Weak Acid. Stainless steels (SS) have exceUent corrosion resistance to weak nitric acid and are the primary materials of constmction for a weak acid process. Low carbon stainless steels are preferred because of their resistance to corrosion at weld points. However, higher grade materials of constmction are required for certain sections of the weak acid process. These are limited to high temperature areas around the gau2e (ca 900°G) and to places in which contact with hot Hquid nitric acid is likely to be experienced (the cooler condenser and tail gas preheater). 

High chromium (20—27%) SS provides better corrosion resistance to nitric acid at elevated temperatures than low carbon SS. It has been used to... 

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