| Mark was smoking his cigar outside the door of his house when he saw a man, a stranger, approaching him. Suddenly he ceased to be visible! Mark, who had long desired to see a ghost, rushed into his house to record the phenomenon. There, seate... Read more of Mark Twain's Story at Scary Stories.ca |  InformationalPrivacy |
Steel MakingSulphurSulphur is another impurity and high sulphur is even a greate... High-chromium Or Rust-proof Steel High-chromium, or what is called stainless steel containing f... Mushet And Bessemer That Mushet was "used" by Ebbw Vale against Bessemer is, perh... Manganese MANGANESE is a metal much like iron. Its chemical symbol is M... Heat Treatment Of Steel Heat treatment consists in heating and cooling metal at defin... The Thermo-couple With the application of the thermo-couple, the measurement of... Heating Of Manganese Steel Another form of heat-treating furnace is that which is used ... Knowing What Takes Place How are we to know if we have given a piece of steel the ver... Application To The Automotive Industry The information given on the various parts of the Liberty eng... Effect Of Different Carburizing Material [Illustrations: FIGS. 33 to 37.] Each of these different p... Carburizing Low-carbon Sleeves Low-carbon sleeves are carburized and pushed on malleable-ir... Carbon Tool Steel Heat to a bright red, about 1,500 to 1,550 deg.F. Do not ham... Pickling The Forgings The forgings were then pickled in a hot solution of either ni... Non-shrinking Oil-hardening Steels Certain steels have a very low rate of expansion and contract... Tungsten Tungsten, as an alloy in steel, has been known and used for a... Nickel-chromium A combination of the characteristics of nickel and the charac... Instructions For Working High-speed Steel Owing to the wide variations in the composition of high-speed... Carbon In Tool Steel Carbon tool steel, or tool steel as it is commonly called, us... Heat Treatment Of Punches And Dies Shears Taps Etc HEATING.--The degree to which tools of the above classes shou... The Theory Of Tempering Steel that has been hardened is generally harder and more br... |
Correction For Cold-junction ErrorsCategory: PYROMETRY AND PYROMETERS The voltage generated by a thermo-couple of an electric pyrometer is dependent on the difference in temperature between its hot junction, inside the furnace, and the cold junction, or opposite end of the thermo-couple to which the copper wires are connected. If the temperature or this cold junction rises and falls, the indications of the instrument will vary, although the hot junction in the furnace may be at a constant temperature. A cold-junction temperature of 75 deg.F., or 25 deg.C., is usually adopted in commercial pyrometers, and the pointer on the pyrometer should stand at this point on the scale when the hot junction is not heated. If the cold-junction temperature rises about 75 deg.F., where base metal thermo-couples are used, the pyrometer will read approximately 1 deg. low for every 1 deg. rise in temperature above 75 deg.F. For example, if the instrument is adjusted for a cold-junction temperature of 75 deg., and the actual cold-junction temperature is 90 deg.F., the pyrometer will read 15 deg. low. If, however, the cold-junction temperature falls below 75 deg.F., the pyrometer will read high instead of low, approximately 1 deg. for every 1 deg. drop in temperature below 75 deg.F. With platinum thermo-couples, the error is approximately 1/2 deg. for 1 deg. change in temperature. Next: Correction By Zero Adjustment Previous: Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer
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