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Steel MakingAnnealingANNEALING can be done by heating to temperatures ranging from... Double Annealing Water annealing consists in heating the piece, allowing it to... Silicon SILICON is a very widespread element (symbol Si), being an es... Carbon In Tool Steel Carbon tool steel, or tool steel as it is commonly called, us... A Satisfactory Luting Mixture A mixture of fireclay and sand will be found very satisfactor... Critical Points One of the most important means of investigating the properti... Annealing Alloy Steel The term alloy steel, from the steel maker's point of view, r... Introduction Of Carbon The matter to which these notes are primarily directed is the... Pyrometers Armor plate makers sometimes use the copper ball or Siemens' ... Temperature Recording And Regulation Each furnace is equipped with pyrometers, but the reading an... Tool Or Crucible Steel Crucible steel can be annealed either in muffled furnace or b... Affinity Of Nickel Steel For Carbon The carbon- and nickel-steel gears are carburized separately... Heat Treatment Of Milling Cutters Drills Reamers Etc THE FIRE.--Gas and electric furnaces designed for high heats ... High-carbon Machinery Steel The carbon content of this steel is above 30 points and is ha... Correction For Cold-junction Errors The voltage generated by a thermo-couple of an electric pyrom... Heat-treating Equipment And Methods For Mass Production The heat-treating department of the Brown-Lipe-Chapin Company... Annealing Of High-speed Steel For annealing high-speed steel, some makers recommend using g... Suggestions For Handling High-speed Steels The following suggestions for handling high-speed steels are ... Heat Treatment Of Gear Blanks This section is based on a paper read before the American Gea... Drop Forging Dies The kind of steel used in the die of course influences the he... |
QuenchingCategory: CASE-HARDENING OR SURFACE-CARBURIZING It is considered good practice to quench alloy steels from the pot, especially if the case is of any appreciable depth. The texture of carbon steel will be weakened by the prolonged high heat of carburizing, so that if we need a tough core, we must reheat it above its critical range, which is about 1,600 deg.F. for soft steel, but lower for manganese and nickel steels. Quenching is done in either water, oil, or air, depending upon the results desired. The steel is then very carefully reheated to refine the case, the temperature varying from 1,350 to 1,450 deg.F., depending on whether the material is an alloy or a simple steel, and quenched in either water or oil. There are many possibilities yet to be developed with the carburizing of alloy steels, which can produce a very tough, tenacious austenitic case which becomes hard on cooling in air, and still retains a soft, pearlitic core. An austenitic case is not necessarily file hard, but has a very great resistance to abrasive wear. The more carbon a steel has to begin with the more slowly will it absorb carbon and the lower the temperature required. Low-carbon steel of from 15 to 20 points is generally used and the carbon brought up to 80 or 85 points. Tool steels may be carbonized as high as 250 points. In addition to the carburizing materials given, a mixture of 40 per cent of barium carbonate and 60 per cent charcoal gives much faster penetration than charcoal, bone or leather. The penetration of this mixture on ordinary low-carbon steel is shown in Fig. 32, over a range of from 2 to 12 hr. Next: Effect Of Different Carburizing Material Previous: Carburizing Material
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