Tungsten alloyed steels

Tungsten Alloyed Steels. Tungsten addition to the steel melt. 

Timgsten sources which can be added to the steel melt are  

Tungsten metal scrap Ferrotungsten Scheelite ore concentrates Melting base 

Tungsten addition as scheelite permits rapid attainment of alloy homogeneity at a recovery of 94%. The costs are significantly lower but the addition is limited to 5% W in steel. Higher amounts increase the slag volume and thus decrease the recovery. 

Addition of melting base offers the advantages of known chemistry, easy charge, and good solubility. 

---

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. 

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. 

High density tungsten alloy machine chips are recovered by oxidation at about 850°C, foUowed by reduction in hydrogen at 700—900°C. Typically, the resultant powders are about 3-p.m grain size and resinter readily. There can be some pickup of refractory materials used in furnace constmction, which must be controUed. This process is important commercially. Eor materials that may be contaminated with other metals or impurities, the preferred recovery process is the wet chemical conversion process used for recovery of tungsten from ores and process wastes. Materials can always be considered for use as additions in alloy steel melting. 

Iron carbide (3 1), Fe C mol wt 179.56 carbon 6.69 wt % density 7.64 g/cm mp 1650°C is obtained from high carbon iron melts as a dark gray air-sensitive powder by anodic isolation with hydrochloric acid. In the microstmcture of steels, cementite appears in the form of etch-resistant grain borders, needles, or lamellae. Fe C powder cannot be sintered with binder metals to produce cemented carbides because Fe C reacts with the binder phase. The hard components in alloy steels, such as chromium steels, are double carbides of the formulas (Cr,Fe)23Cg, (Fe,Cr)2C3, or (Fe,Cr)3C2, that derive from the binary chromium carbides, and can also contain tungsten or molybdenum. These double carbides are related to Tj-carbides, ternary compounds of the general formula M M C where M = iron metal M = refractory transition metal. 

The simple analytieal proeedure of tungsten determination in high alloy steel and niekel base alloys by atomie emission speetrometry with induetively eoupled plasma (AES-ICP) was developed. Proposed teehnique ineludes the dissolution of 0.1-0.5 g of material in mixed aeids (25 ml HCl, 3 ml HNO, 5 ml HF), eomplexation of tungsten by 9 % solution of oxalie aeid and measurement of tungsten emission intensity (k = 207.911 nm). 

A simple ealibration eurve based on distilled water is suitable for tungsten determination (linearity range is 1-50 mg/dm of W), no interferenee from Fe, Co, Cr, Ni was found. The aeeuraey of the method is eonfirmedby analysis of eertified referenee materials of high alloy steels and niekel based alloys (in range of 0.3 to 15 % W). The analyzed values are agreeing well with the eertified values. 

Solid-Type Stabilizers. (See Figure 4-180.) These stabilizers have no moving or replaceable parts, and consist of mandrel and blades that can be one piece alloy steel (integral blade stabilizer) or blades welded on the mandrel (weld-on blade stabilizer). The blades can be straight, or spiral, and their working surface is either hardfaced with tungsten carbide inserts or diamonds [57,58]. 

Stabilizer. Hardfacing Stabilizer. Alloy steel with tungsten carbide hardfacing. (Servco) compacts. (Servco)... 

Chromium compounds Cr203 surface scale Nickel- chromium—iron alloys Nickel-chromium— molybdenum (tungsten) alloys Ni-Cr alloys analytical methods, 6 502-514 composition of metal compared to chromium ferroalloys, 6 501t dispersoid former, 2 325, 327 disposal, 6 519-521 economic aspects, 6 496—500 effect on cobalt alloys, 7 220 effect on stainless steel corrosion resistance, 7 809... 

It is interesting to note that Brenner and Riddell (2-4) accidentally encountered electroless deposition of nickel and cobalt during electrodeposition of nickel-tungsten and cobalt-tungsten alloys (in the presence of sodium hypophosphite) on steel tubes in order to produce material with better hardness than that of steel. They found deposition efficiency higher than 100%, which was explained by an electroless deposition contribution to the electrodeposition process. 

Metals that are generally stiffer than brass include steels, nickel alloys, molybdennm alloys, and tungsten alloys. All but steel are generally expensive. Molybdennm and tnngsten alloys have high melting points. 

The metals and alloys that have been under test at National Northern were before the publication of Ref 7 the following plain carbon steels, alloy steels, stainless steels Ni, Al, Mg, Ti Cu alloys Zircalloy—2 Ta, U, Ber, Niobium (CoLumbium), W (Wolfram or Tungsten) and Mo. They have been in either one or more of the following starting forms sheet, plate, cylinders, cones, powders and pellets... 

Molybdenum is used in a variety of catalysts, especially combined with cobalt in desulfiirization of petroleum. Another major use for both metals is in alloy steels to which they impart hardness and strength. Tungsten is also used in lamp filaments. 

---