| Once, while Jesus was journeying about, He passed near a town where a man named Jairus lived. This man was a ruler in the synagogue, and he had just one little daughter about twelve years of age. At the time that Jesus was there the little ... Read more of THE STORY OF JAIRUS'S DAUGHTER at Children Stories.ca |  InformationalPrivacy |
Steel MakingSulphurSulphur is another impurity and high sulphur is even a greate... Connecting Rods The material used for all connecting rods on the Liberty engi... Correction By Zero Adjustment Many pyrometers are supplied with a zero adjuster, by means ... Making Steel Balls Steel balls are made from rods or coils according to size, st... Steel Can Be Worked Cold As noted above, steel can be worked cold, as in the case of ... Using Illuminating Gas The choice of a carburizing furnace depends greatly on the fa... The Electric Process The fourth method of manufacturing steel is by the electric f... Phosphorus Phosphorus is one of the impurities in steel, and it has been... Complete Calibration Of Pyrometers For the complete calibration of a thermo-couple of unknown e... Temperature Recording And Regulation Each furnace is equipped with pyrometers, but the reading an... Hardening High-speed Steel In forging use coke for fuel in the forge. Heat steel slowly ... Refining The Grain This is remedied by reheating the piece to a temperature slig... Judging The Heat Of Steel While the use of a pyrometer is of course the only way to hav... Heat-treating Department The heat-treating department occupies an L-shaped building. ... Crankshaft The crankshaft was the most highly stressed part of the entir... Hardening Carbon Steel For Tools For years the toolmaker had full sway in regard to make of st... Silicon Silicon prevents, to a large extent, defects such as gas bubb... Manganese MANGANESE is a metal much like iron. Its chemical symbol is M... The Forging Of Steel So much depends upon the forging of steel that this operation... The Effect Of Tempering On Water-quenched Gages The following information has been supplied by Automatic and ... |
HardeningCategory: ALLOYS AND THEIR EFFECT UPON STEEL The forgings can be hardened by cooling in still air or quenching in oil or water from a temperature between 1,650 and 1,750 deg.F. The physical properties do not vary greatly when the carbon is within the range of composition given, or when the steel is hardened and tempered in air, oil, or water. When used for valves the following specification of physical properties have been used: Yield point, pounds per square inch 70,000 Tensile strength, pounds per square inch 90,000 Elongation in 2 in., per cent 18 Reduction of area, per cent 50 The usual heat treatment is to quench in oil from 1,650 deg.F. and temper or draw at 1,100 to 1,200 deg.F. One valve manufacturer stated that valves of this steel are hardened by heating the previously annealed valves to 1,650 deg.F. and cooling in still air. This treatment gives a scleroscope hardness of about 50. In addition to use in valves this steel should prove very satisfactory for shafting for water-pumps and other automobile parts subject to objectionable corrosion. TABLE 2.--COMPARISON OF PHYSICAL PROPERTIES FOR HIGH-CHROMIUM STEELS OF DIFFERENT CARBON CONTENT -------------------------------------------------------------------------- C 0.20 C 0.27 C 0.50 Mn 0.45 Mn 0.50 Cr 12.56 Cr 12.24 Cr 14.84 ----------------------------------------------------------------------- Quenched in oil from degrees Fahrenheit 1,600 1,600 1,650 Tempered at degrees Fahrenheit 1,160 1,080 1,100 Yield point, pounds per square inch 78,300 75,000 91,616 Tensile strength, pounds per square inch 104,600 104,250 123,648 Elongation in 2 in., per cent 25.0 23.5 14.5 Reduction of area, per cent 52.5 51.4 33.5 -------------------------------------------------------------------------- TABLE 3.--COMPARISON OF PHYSICAL PROPERTIES BETWEEN AIR, OIL AND WATER-HARDENED STEEL HAVING CHEMICAL ANALYSIS IN PERCENTAGE OF ------------------------------------------------------------------------- Carbon 0.24 Manganese 0.30 Phosphorus 0.035 Sulphur 0.035 Chromium 12.85 Silicon 0.20 ------------------------------------------------------------------------- Hardened Elastic Tensile Hardening from, Tempered limit, strength,ElongationReduction medium degrees at, degrees per lb. lb. Per in 2 in. of area, FahrenheitFahrenheit sq. in. sq. in. per cent per cent ------------------------------------------------------------------- 930 158,815 192,415 13.0 40.5 1,100 99,680 120,065 21.0 59.2 Air 1,650 1,300 70,785 101,250 26.0 64.6 1,380 66,080 98,335 28.0 63.6 1,470 70,785 96,990 27.0 64.7 ------------------------------------------------------------------- 930 163,070 202,720 8.0 18.2 Oil 1,650 1,100 88,255 116,480 20.0 56.9 1,300 77,950 105,505 25.5 63.8 1,380 88,255 98,785 27.0 66.3 ------------------------------------------------------------------- 930 158,815 202,050 12.0 34.2 Water 1,650 1,100 90,270 120,735 22.0 59.8 1,300 66,080 102,590 25.8 64.8 1,380 67,200 97,890 27.0 65.2 ------------------------------------------------------------------------- This steel can be drawn into wire, rolled into sheets and strips and drawn into seamless tubes. Next: Corrosion Previous: Annealing
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