| Once upon a time there were two men who had gone cliff climbing. Suddenly, one man lost his footing and went tumbling down to the bottom. The other man frantically screamed, "Roger!", and was relieved to hear a faint reply. "Okay Rodge," shoute... Read more of Idiot resuce at Free Jokes.ca |  InformationalPrivacy |
Steel MakingHardening OperationHardening a gear is accomplished as follows: The gear is tak... High Speed Steel For centuries the secret art of making tool steel was handed ... Heat Treatment Of Punches And Dies Shears Taps Etc HEATING.--The degree to which tools of the above classes shou... Preventing Carburizing By Copper-plating Copper-plating has been found effective and must have a thick... Care In Annealing Not only will benefits in machining be found by careful anne... Effect Of Different Carburizing Material [Illustrations: FIGS. 33 to 37.] Each of these different p... Rate Of Absorption According to Guillet, the absorption of carbon is favored by ... Sulphur Sulphur is another impurity and high sulphur is even a greate... Typical Oil-fired Furnaces Several types of standard oil-fired furnaces are shown herew... Phosphorus Phosphorus is one of the impurities in steel, and it has been... Refining The Grain This is remedied by reheating the piece to a temperature slig... The Quenching Tank The quenching tank is an important feature of apparatus in c... Properties Of Alloy Steels The following table shows the percentages of carbon, manganes... Preventing Cracks In Hardening The blacksmith in the small shop, where equipment is usually ... Vanadium Vanadium has a very marked effect upon alloy steels rich in c... Silicon Silicon prevents, to a large extent, defects such as gas bubb... Detrimental Elements Sulphur and phosphorus are two elements known to be detrimen... Making Steel Balls Steel balls are made from rods or coils according to size, st... Placing Of Pyrometers When installing a pyrometer, care should be taken that it re... Quenching Tool Steel To secure proper hardness, the cooling of quenching of steel ... |
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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