Tool steels molybdenum

Alloys.1—The most important alloy of molybdenum is ferro-molybdenum, which is used as an addition to steel. The effect of molybdenum on steel is similar to that of tungsten, but is more marked the tensile strength is increased and the elastic limit raised. For highspeed tool-steels molybdenum is often used in conjunction with tungsten. It has been found that the addition of molybdenum in small quantities (up to 15 per cent.) to steel increases the liability to corrosion, especially in acid and salt solutions. An important use of steels containing 3 to 4 per cent, of molybdenum and 1-0 to 1-5 per cent, of carbon is for the manufacture of permanent magnets. ... 

Powder Formation. Metallic powders can be formed by any number of techniques, including the reduction of corresponding oxides and salts, the thermal dissociation of metal compounds, electrolysis, atomization, gas-phase synthesis or decomposition, or mechanical attrition. The atomization method is the one most commonly used, because it can produce powders from alloys as well as from pure metals. In the atomization process, a molten metal is forced through an orifice and the stream is broken up with a jet of water or gas. The molten metal forms droplets to minimize the surface area, which solidify very rapidly. Currently, iron-nickel-molybdenum alloys, stainless steels, tool steels, nickel alloys, titanium alloys, and aluminum alloys, as well as many pure metals, are manufactured by atomization processes. 

Niobium in Tool Steels. In the matrix method of tool-steel development, the composition of the heat-treated matrix determines the steel s initial composition. Carbide volume-fraction requirements then are calculated, based upon historical data, and the carbon content is adjusted accordingly. This approach has been used to design new steels in which niobium is substituted for all or part of the vanadium present as carbides in the heat-treated material. Niobium provides dispersion hardening and grain refinement, and forms carbides that are as hard as vanadium, tungsten, and molybdenum carbides. 

High speed steels are highly alloyed tool steels which exhibit enhanced hardness and wear resistance at high temperatures. These steels have a high carbon content and varying amounts of chromium, molybdenum, tungsten and vanadium. 

More Mo is consumed annually than any other refractory metal. The major use for Mo is as an alloying element in alloy steels, tool steels, stainless steels, Ni-based and Co-based superalloys. In these materials, it increases the hardenability, toughness, high-temperature strength, and corrosion resistance. Molybdenum is important in the missile industry, where it is used for high-temperature structural parts, such as nozzles, leading edges of control surfaces, support vanes, struts, reentry cones, radiation shields and heat sinks. In the electrical and electronic industries. Mo is... 

The undesirable properties said to be produced by molybdenum are red-shortness, and the appearance of cracks while rolling or forging. This results in a lack of dependability which is not permissible. In molybdenum tool steel, some users report that cracks are produced by the quenching process others that they do not hold a thin cutting edge after retreatment as well as before some find that such tools show irregular cutting speeds, that the material is seamy, and contains physical imperfections. 

A.P.G. Gervasio, G.C. Luca, A.A. Menegario, B.F. Reis, H. Bergamin-Filho, On-line electrolytic dissolution of alloys in flow injection analysis. Determination of iron, tungsten, molybdenum, vanadium and chromium in tool steels by inductively coupled plasma atomic emission spectrometry, Anal. Chim. Acta 405 (2000) 213. 

A.P.G. Gervasio, P.R. Fortes, S.R.P. Meneses, C.E.S. Miranda, E.A.G. Zagatto, An improved flow-injection system for spectrophotometric determination of molybdenum and tungsten in tool steels, Talanta 69 (2006) 927. 

Hardened tool steel is another kind of difficult-to-machine material that is studied in this chapter. M7 is molybdenum-type high-speed steel designed with higher carbon and vanadium to provide high hardness (up to HRC 65-67) and good wear resistance. 

Molybdenum (Mo). A minute amount of molybdenum improves certain metallurgical properties of alloy steels such as deep hardening and fracture toughness. Molybdenum is used often in larger amounts in certain high-speed-tool steels to replace tungsten, primarily for economic reasons, often with nearly equivalent results. 

Molybdenum-alloy high-speed-tool steels ... 

Molybdenum improves the wear resistance in tool steels, especially in high-speed steels. This again makes use of its tendency to form hard carbides. 

Tool steels are high carbon steels (up to about 1 wt % C) that contain appreciable amounts of tungsten or molybdenum. These elements increase the ability of a tool steel to retain its hardness to relatively high temperature. This property is important since most metal cutting tools... 

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