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Show HIS EFFECT OF iupii se of Metal Produces Self-Hardening Self-Hardening Steel of Great Toughness. JolvNlcnum, Its u?o ami effect In tho mifaoturo of hlKh-gnula steel, Is fully l!ned In a circular recently issued by Colorado School of Mines. Chen molybdenum or on of Its alloys ' free from objectionable hnpm-i'.ies en ndded to steel in proper amount. if tho steel is given proper treatment. addition is toxin-! lo i:npart to the ?1 valuable propo. ties. U-1 . a?n" ied tensile strengtn. hisM ductility, snoM and durability. Although moytti-um moytti-um and tungsten do not have exactly liar effects on steel. It has been defined de-fined that molybdenum has an ef-tiveness ef-tiveness equivalent to from two to e times the amount of tungsten, vbdenum Is used In combination with Dinlum. or mansranese. and carbon to iuce self-hardenini? steel, which Is 1 to be tougher than the correspond-tunpsten correspond-tunpsten steel, tvpical eelf-hrxrder.insr steel la one 'taininpr 4 to 6 per cent molybdenum, j 2 per cent chromium, and 1.S5 per t carbon. Small percentages of mo- . lenum are valuable in high-speed tool A characteristic steel of this type me. containing 1.5 to 2 per cent mo-lenum, mo-lenum, 4 to -4.5 per cent chromium, to IS per cent tungsten, and .06 per t carbon. Molybdenum is also used i:gh-speed steels where cobalt is used conjunction with tungsten. This type jteel contains O."o to 1.5 per cent mo-lenum, mo-lenum, 4 to 55.5 per cent cobalt, and :o 15 per cent tungsten. Molybdenum ised In small amount, less than 1 per t. In conjunction with tungsten, co-., co-., chromium and vanadium, in a hlgh-sd hlgh-sd tool steel called Iridium steel, which - e ported to do 60 per cent more work n the best tungsten steel, he introduction of high-speed tool :1s has completely revolutionized male ma-le shop practice, and flanges and es in which holes were formerly cored ranched are now drilled to advantage. h-speed tool steels are now made that cut 500 feet a minute on steel, and 1 cast iron at the rate of twenty-five : es a minute. Planing speeds have r i increased to eighty feet a minute. . Js used In making permanent mag- . contain 2 to 3 per cent molybdenum, .- to 0.7 per cent carbon, and 0.5 per : chromium. Acldproof steel contains 5 per cent molybdenum and 10 per1 i chromium. An alloy containing 2 ! per cent molybdenum, 60 per cent mium, and 35 per cent iron is said eslst even the action If boiling aqua - i. z eel having h'.gh tensile strength and -; .lc limit contains 0.C5 to 0.5 per cent i: "bdenum, 1 per cent chromium, and . 3 per cent nickel. Such steel has - !al value for crank shafts, propeller " :s, and other machine parts that are cted to alternating and repeated ''ses, viz., In frames and axles of au-V au-V -biles and railroad rolling siock. Such is also employed in making larse ' and rifle barrels, where it has the ntage of being highly resistant to the T:-ve action of the gases generated by ii sives. The addition of 0.o to 0.5 t cent molybdenum is advantageous in r-manufacture of armor plate and ds for small guns. The molybdenum id to make the steel softer when it is aled so that It can be planed more :''Iy, and, upon hardening, the molyb- , : m Increases Its tensile strength. |