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Steel MakingA Chromium-cobalt SteelThe Latrobe Steel Company make a high-speed steel without tun... Heat Treatment Of Punches And Dies Shears Taps Etc HEATING.--The degree to which tools of the above classes shou... Heat Treatment Of Milling Cutters Drills Reamers Etc THE FIRE.--Gas and electric furnaces designed for high heats ... Carbon-steel Forgings Low-stressed, carbon-steel forgings include such parts as car... Hardening The forgings can be hardened by cooling in still air or quen... Complete Calibration Of Pyrometers For the complete calibration of a thermo-couple of unknown e... Chromium Chromium when alloyed with steel, has the characteristic func... Annealing Method Forgings which are too hard to machine are put in pots with ... Effect Of Different Carburizing Material [Illustrations: FIGS. 33 to 37.] Each of these different p... Alloying Elements Commercial steels of even the simplest types are therefore p... Take Time For Hardening Uneven heating and poor quenching has caused loss of many ve... Carbon In Tool Steel Carbon tool steel, or tool steel as it is commonly called, us... Correction For Cold-junction Errors The voltage generated by a thermo-couple of an electric pyrom... Temperatures To Use As soon as the temperature of the steel reaches 100 deg.C. (... Open Hearth Process The open hearth furnace consists of a big brick room with a l... 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... Preparing Parts For Local Case-hardening At the works of the Dayton Engineering Laboratories Company, ... The Forging Of Steel So much depends upon the forging of steel that this operation... Gas Consumption For Carburizing Although the advantages offered by the gas-fired furnace for ... |
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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