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Steel MakingStandard AnalysisThe selection of a standard analysis by the manufacturer is t... Alloying Elements Commercial steels of even the simplest types are therefore p... Flange Shields For Furnaces Such portable flame shields as the one illustrated in Fig. 1... Rate Of Absorption According to Guillet, the absorption of carbon is favored by ... Double Annealing Water annealing consists in heating the piece, allowing it to... Preventing Carburizing By Copper-plating Copper-plating has been found effective and must have a thick... Annealing In Bone Steel and cast iron may both be annealed in granulated bone. ... Molybdenum Molybdenum steels have been made commercially for twenty-five... Steel Worked In Austenitic State As a general rule steel should be worked when it is in the a... Robert Mushet Robert (Forester) Mushet (1811-1891), born in the Forest of D... Placing The Thermo-couples The following illustrations from the Taylor Instrument Compan... Open Hearth Process The open hearth furnace consists of a big brick room with a l... Steel For Chisels And Punches The highest grades of carbon or tempering steels are to be re... Correction By Zero Adjustment Many pyrometers are supplied with a zero adjuster, by means ... Separating The Work From The Compound During the pulling of the heat, the pots are dumped upon a ca... Detrimental Elements Sulphur and phosphorus are two elements known to be detrimen... Temperature For Annealing Theoretically, annealing should be accomplished at a tempera... Heavy Forging Practice In heavy forging practice where the metal is being worked at... The Quenching Tank The quenching tank is an important feature of apparatus in c... Introduction Of Carbon The matter to which these notes are primarily directed is the... |
SiliconCategory: COMPOSITION AND PROPERTIES OF STEEL SILICON is a very widespread element (symbol Si), being an essential constituent of nearly all the rocks of the earth. It is similar to carbon in many of its chemical properties; for instance it burns very readily in oxygen, and consequently native silicon is unknown--it is always found in combination with one or more other elements. When it bums, each atom of silicon unites with two atoms of oxygen to form a compound known to chemists as silica (SiO2), and to the small boy as sand and agate. Iron ore (an oxide of iron) contains more or less sand and dirt mixed in it when it is mined, and not only the iron oxide but also some of the silicon oxide is robbed of its oxygen by the smelting process. Pig iron--the product of the blast furnace--therefore contains from 1 to 3 per cent of silicon, and some silicon remains in the metal after it has been purified and converted into steel. However, silicon, as noted above, burns very readily in oxygen, and this property is of good use in steel making. At the end of the steel-making process the metal contains more or less oxygen, which must be removed. This is sometimes done (especially in the so-called acid process) by adding a small amount of silicon to the hot metal just before it leaves the furnace, and stirring it in. It thereupon abstracts oxygen from the metal wherever it finds it, changing to silica (SiO2) which rises and floats on the surface of the cleaned metal. Most of the silicon remaining in the metal is an excess over that which is required to remove the dangerous oxygen, and the final analysis of many steels show enough silicon (from 0.20 to 0.40) to make sure that this step in the manufacture has been properly done. Next: Manganese Previous: Phosphorus
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