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Steel MakingThe Theory Of TemperingSteel that has been hardened is generally harder and more br... Carburizing Material The simplest carburizing substance is charcoal. It is also th... Carbon In Tool Steel Carbon tool steel, or tool steel as it is commonly called, us... Robert Mushet Robert (Forester) Mushet (1811-1891), born in the Forest of D... Temperature Recording And Regulation Each furnace is equipped with pyrometers, but the reading an... Composition Of Transmission-gear Steel If the nickel content of this steel is eliminated, and the pe... Complete Calibration Of Pyrometers For the complete calibration of a thermo-couple of unknown e... Protective Screens For Furnaces Workmen needlessly exposed to the flames, heat and glare from... Leeds And Northrup Optical Pyrometer The principles of this very popular method of measuring tempe... Heat Treatment Of Lathe Planer And Similar Tools FIRE.--For these tools a good fire is one made of hard foundr... Properties Of Steel Steels are known by certain tests. Early tests were more or l... Highly Stressed Parts The highly stressed parts on the Liberty engine consisted of ... Application To The Automotive Industry The information given on the various parts of the Liberty eng... Knowing What Takes Place How are we to know if we have given a piece of steel the ver... Compensating Leads By the use of compensating leads, formed of the same materia... Connecting Rods The material used for all connecting rods on the Liberty engi... Carburizing Low-carbon Sleeves Low-carbon sleeves are carburized and pushed on malleable-ir... S A E Heat Treatments The Society of Automotive Engineers have adopted certain heat... Separating The Work From The Compound During the pulling of the heat, the pots are dumped upon a ca... Rate Of Absorption According to Guillet, the absorption of carbon is favored by ... |
Hardening High-speed SteelsCategory: HIGH-SPEED STEEL We will now take up the matter of hardening high-speed steels. The most ordinary tools used are for lathes and planers. The forging should be done at carbon-steel heat. Rough-grind while still hot and preheat to about carbon-steel hardening heat, then heat quickly in high-speed furnace to white heat, and quench in oil. If a very hard substance is to be cut, the point of tool may be quenched in kerosene or water and when nearly black, finish cooling in oil. Tempering must be done to suit the material to be cut. For cutting cast iron, brass castings, or hard steel, tempering should be done merely to take strains out of steel. On ordinary machinery steel or nickel steel the temper can be drawn to a dark blue or up to 900 deg.F. If the tool is of a special form or character, the risk of melting or scaling the point cannot be taken. In these cases the tool should be packed, but if there is no packing equipment, a tool can be heated to as high heat as is safe without risk to cutting edges, and cyanide or prussiate of potash can be sprinkled over the face and then quenched in oil. Some very adverse criticism may be heard on this point, but experience has proved that such tools will stand up very nicely and be perfectly free from scales or pipes. Where packing cannot be done, milling cutters, and tools to be hardened all over, can be placed in muffled furnace, brought to 2,220 deg. and quenched in oil. All such tools, however, must be preheated slowly to 1,400 to 1,500 deg. then placed in a high-speed furnace and brought up quickly. Do not soak high-speed steel at high heats. Quench in oil. We must bear in mind that the heating furnace is likely to expand tools, therefore provision must be made to leave extra stock to take care of such expansion. Tools with shanks such as counter bores, taps, reamers, drills, etc., should be heated no further than they are wanted hard, and quench in oil. If a forge is not at hand and heating must be done, use a muffle furnace and cover small shanks with a paste from fire clay or ground asbestos. Hollow mills, spring threading dies, and large cutting tools with small shanks should have the holes thoroughly packed or covered with asbestos cement as far as they are wanted soft. Next: Cutting-off Steel From Bar Previous: Quality And Structure
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