Tungsten in Steel

Tungsten alloying is important mainly for the following steel grades  

High speed steels (HSS) consume by far the most tungsten in steelmaking, although they account for less than 0.02% of the total steel production (1997 about 700 million metric tons). In fact the tungsten story in special steel making is the story of high speed steel [8.8]. 

By shifting the eutectoid point to lower carbon concentrations, tungsten increases the amount of undissolved and excess carbide in the hardened steel. Tungsten is a carbideforming element and binds the carbon to form straight tungsten carbide or combines with 

Other alloying elements to form complex carbides (MeC, M23C6). The chemistry of these carbides depends on the concentration of carbon and the alloying elements present as well as on the heat treatment applied. For the same level of carbon in the steel tungsten will produce a larger carbide voliune than other allo5ung elements [8.3], 

The effects of tungsten on steel properties in terms of carbide volume, shape and distribution, and fine-grained structure are  

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Procedure (tungsten in steel). Dissolve 0.5 g of the steel, accurately weighed, in 30 mL of the mixed acid by heating, oxidise with concentrated nitric acid, and evaporate to fuming. Extract with 100 mL water, boil, transfer to a 500 mL... 

From an environmental standpoint, cemented carbide tools are preferable to high speed steel because any tungsten in steel is lost by dilution (see Section 11.1) in contrast to cemented carbide scrap, which is a valuable source for recycling [8.10]. 

M. Kroneis, Tungsten in Steel, in Proc. 1st Int. Tungsten Symposium, Stockholm, pp. 96-107, Mining Journals Books Ltd., London (1979). 

Tungsten hexafluoride is shipped as a Hquid under its own vapor pressure in nickel or steel cylinders in quantities of 45 kilograms per cylinder or less however, it has been shown that the purity of WF packaged in steel cylinders can degrade over time (21). It is classified as a corrosive Hquid by the... 

Niobium is important as an alloy addition in steels (see Steel). This use consumes over 90% of the niobium produced. Niobium is also vital as an alloying element in superalloys for aircraft turbine engines. Other uses, mainly in aerospace appHcations, take advantage of its heat resistance when alloyed singly or with groups of elements such as titanium, tirconium, hafnium, or tungsten. Niobium alloyed with titanium or with tin is also important in the superconductor industry (see High temperature alloys Refractories). 

OPTIMIZATION OF THE METHOD FOR TUNGSTEN DETERMINATION IN STEELS AND ALLOYS BY INDUCTIVELY... 

Tungsten and tungsten carbide harden steel and gives temperature resistance. It has a fixed spot in steel for tools and drill heads. 

Hydrogen chloride gas may be stored in steel cyhnders free of contaminants. Monel, pure nickel, or its aUoy, inconel, may also be used for storage and transportation up to 500°C. Hydrochloric acid may be stored in glass bottles or in containers made up of tantalum or tantalum-molybdenum alloys, or other alloys of zirconium, molybdenum, and tungsten. 

Armor-piercing (AP) ammunition has a projectile or projectile core constructed entirely from a combination of tungsten alloys, steel, iron, brass, bronze, beryllium copper, or depleted uranium. The most effective AP bullets are usually confined to rifle bullets, as velocity and range are important factors in AP requirements. Some revolver and pistol ammunition is described as metal piercing but, although it would be effective against vehicle bodywork and some body armor, it would be ineffective against heavy armor plate. AP bullets are, with very few exceptions, jacketed. 

The term rarer elements as originally employed in the sense of their comparative rare occurrence and limited availability must now, in a number of cases, be regarded as a misnomer. Large quantities of some of these elements are utilized annually, and the range of their application is slowly but surely widening. A few examples may be mentioned the use of molybdenum, tungsten, titanium, and beryllium in the steel industry, of tungsten in the manufacture of incandescent lamps, and of titanium and uranium in the paint industry. The interpretation of the term rarer elements, as applied to the elements described in this chapter, is perhaps best accepted in the sense of their comparatively rare occurrence in routine qualitative analysis. 

For this work, the liquid nitrogen HPGe detector and MCA in a standard system for field measurements (Iso-Cart) was replaced by a portable HPGe detector with built-in MCA (Trans-SPEC-100). The detector is nominally 40% relative efficiency a size commonly used for field measurements. The tungsten and steel collimators are cylindrical sleeves surrounding the crystal and projecting forward. The absorbing material is 4.7 mm thick. 

Corresponding Co compounds may form during liquid-phase sintering of cemented carbides if the carbon balance is low analogous Fe compounds (containing also Mo, V, and Cr) occur in tungsten alloyed steel. 

The application of tungsten metal which, at the beginning of the 20th century, was used only as a filament in incandescent bulbs and as alloying element in steel, as well as of its alloys, is nowadays very widespread and covers quite different fields such as lighting, electronics, high-temperature technology, medicine, aviation, military uses, sports, and so on. 

W-Cu, V-ThO2). Electrical discharge machining allows close dimensional tolerances, accuracy of form, and a high-quality surface finish to be achieved. Both hardened steels and hardmetals can be machined (Fig. 7.12). Tungsten in wire eroding is not only used as a guide and contact for the wire electrodes, but also as erosion wire. 

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