The simultaneous determination of arsenic,antimony and bismuth in ferrotungsten was studied by inductively coupled plasma atomic emission spectrometry.The sample was decomposed with oxalic acid and hydrogen peroxide.In the medium of mixed acid,tungsten was converted to tungstate precipitates and thus separated from sample solution.When residual tungsten in sample solution was less than 150 μg/mL,it did not interfere in the determination.The interference of residual tungsten could be eliminated by the background correction mode and matrix matching. The proposed method has been applied to the determination of arsenic,antimony and bismuth in ferro-tungsten,with the recoveries of 95 %-105 %,and the relative standard deviation(RSD) of 0.86 %-3.6 %.



 

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An inductively coupled plasma atomic emission spectrometry (ICP—AES) procedure has been developed for the determination of aluminium, cobalt, chromium, copper, manganese, molybdenum, nickel, silicon, titanium and vanadium in ferrotungsten. The sample is dissolved by a combination oxalic acid and hydrogen peroxide and the decomposition is completed with a mixture of sulphuric and phosphoric acids in a PTFE vessel without application of hydrofluoric acid. In this way silicon is quantitatively converted into a solution form. No separation of elements from the matrix is required. Calibration graphs have been prepared using synthetic standard samples and verified by means of the Czechoslovak standard ferrotungsten and analysed ferrotungsten samples. For comparison, the samples were analysed by flame atomic absorption spectrometry. The silicon content was also verified by gravimetric and titrimetric methods. The results and accuracy of the method are discussed.

 

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The following content is the other part of GTAW development on tungsten electrode.

Initially, the electrode overheated quickly and, despite tungsten's high melting temperature, particles of tungsten were transferred to the weld. To address this problem, the polarity of the electrode was changed from positive to negative, but the change made it unsuitable for welding many non-ferrous materials. Finally, the development of alternating current units made it possible to stabilize the arc and produce high quality aluminum and magnesium welds.

Developments continued during the following decades. Linde developed water-cooled torches that helped prevent overheating when welding with high currents. During the 1950s, as the process continued to gain popularity, some users turned to carbon dioxide as an alternative to the more expensive welding atmospheres consisting of argon and helium, but this proved unacceptable for welding aluminum and magnesium because it reduced weld quality, so it is rarely used with GTAW today. The use of any shielding gas containing an oxygen compound, such as carbon dioxide, quickly contaminates the tungsten electrode, making it unsuitable for the TIG process. In 1953, a new process based on GTAW was developed, called plasma arc welding. It affords greater control and improves weld quality by using a nozzle to focus the electric arc, but is largely limited to automated systems, whereas GTAW remains primarily a manual, hand-held method. Development within the GTAW process has continued as well, and today a number of variations exist. Among the most popular are the pulsed-current, manual programmed, hot-wire, dabber, and increased penetration GTAW methods. The following content is the other part of GTAW development on tungsten electrode.

The electrode overheated quickly initially and tungsten particles were transferred to the weld in spite of tungsten's high melting temperature. To deal with this problem, the electrode polarity was changed from positive to negative, but the change made it unsuitable for welding many non-ferrous materials. Finally, the development of alternating current units made it possible to stabilize the arc and produce high quality aluminum and magnesium welds.

Developments continued during the following decades. Linde developed water-cooled torches that helped prevent overheating when welding with high currents. During the 1950s, as the process continued to gain popularity, some users turned to carbon dioxide as an alternative to the more expensive welding atmospheres consisting of argon and helium, but this proved unacceptable for welding aluminum and magnesium because it reduced weld quality, so it is rarely used with GTAW today. The use of any shielding gas containing an oxygen compound, such as carbon dioxide, quickly contaminates the tungsten electrode, making it unsuitable for the TIG process. In 1953, a new process based on GTAW was developed, called plasma arc welding. It affords greater control and improves weld quality by using a nozzle to focus the electric arc, but is largely limited to automated systems, whereas GTAW remains primarily a manual, hand-held method. Development within the GTAW process has continued as well, and today a number of variations exist. Among the most popular are the pulsed-current, manual programmed, hot-wire, dabber, and increased penetration GTAW methods. 

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The following content is one part of GTAW development on tungsten electrode.

Arc welding develop slowly after the discovery of short pulsed electric arc in 1800 by Humphry Davy, and of the continuous electric arc in 1802 by Vasily Petrov. C.L.Coffin had the idea of welding in an inert gas atmosphere in 1890, but even in the early 20th century, because these metals react rapidly with air and result in porous, dross - filled welds, welding non-ferrous materials(such as, aluminum and magnesium), remained difficult. Processes using flux-covered electrodes didn’t keep the weld area from contamination well. To solve the problem, bottled inert gases were applied at the eailier1930s. A few years later, a direct current, gas-shielded welding process emerged in the aircraft industry for welding magnesium.

Russell Meredith of Northrop Aircraft perfected the process in 1941. Because it used a tungsten electrode arc and helium as a shielding gas, Meredith named the process Heliarc, but it is often referred to as tungsten inert gas welding (TIG); in parts of the world where tungsten is called wolfram, it is known as WIG. The American Welding Society's official term is gas tungsten arc welding (GTAW).  Linde Air Products developed a wide range of air-cooled and water-cooled torches, gas lenses to improve shielding, and other accessories that increased the using of the process. 

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With the continuous development and improvement of TIG welding (Tungsten Inert Gas), plasma welding, spraying, cutting and other technologies, people have put forward higher requirements to electrode material performance; certainly, including cerium tungsten electrode, there are several requirements of cerium tungsten electrode welding performance showing in the following:

(1) Increasing the arc performance - lower work function (that is, the need for better active substance and content);

(2) Applies to more welding atmosphere - the need for greater chemical stability;

(3) Also requires that they have a better material structure;

(4) Under high temperature conditions, it is able to put up with stream erosion;

(5) What is more, the mort important point is the one that, requiring it without radioactivity, to eliminate the radioactivity that to harm the environment and human health. The following is a comparative on cerium tungsten electrode and thorium tungsten electrode performance:

(1) Compared to the thorium tungsten electrode, cerium tungsten electrode work function material, oxidation resistance and X-ray dose and other properties are significantly improved.

(2) Cerium tungsten electrode influenced by the decrease of cathode spot reduce and the lower of cathode voltage drop, so that the arc emission current density increases, which raising the minimum arc current, the allowable current and breaking arc spacing and other properties. These parameters will increase as the increase of the content of cerium oxide in the experimental range, and during plasma cutting, its ends will be rendered 'natural sharpened' characteristics.

(3) Cerium tungsten electrode melting deep, weld width, burning rate and the reliability of repeated arc is superior to thorium tungsten electrode. During welding the ultra-thin foil devices and precious metals, the performance of 4% cerium tungsten electrode is better.

 

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A rapid analysis method of X-ray fluorescence spectrometry for determining tungsten in ferrotungsten was established with pure iron as flux and centrifugal casting method for sample preparation.The result indicated tungsten had excellent distribution uniformity in sample after melting.No significant difference existed among samples after melting.Meanwhile,test measurement and exclusion were conducted on the potential spectral overlap interference factors in the sample.National standard sample and manually prepared calibration samples were used to draw calibration curve,with linearity scope of 50.00%-85.00%.A comparison was conducted between the testing result of gravimetric method and the proposed method,and the difference was within ±0.20%.The method can meet the the routine testing requirements for fast determination of tungsten in ferrotungsten.

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Concentrate or Not: Non-concentrate

Shape: Lump or powder

Alloy or Not: Is Alloy

Dimensions: 10 to 130mm

HS Code: 7202801000

Model Number: FeW80-A, FeW80-B, FeW80-C, FeW70

Chemical Composition: Fe, W, C, P, S, Si, MN, Cu, As, Bi...

Packaging Detail: 100kg per iron bucket

Specifications:

1. Properties: Wolfram is one of the important alloy elements which are used to make special steel. While Wolfram reduce a little elongation rate of steel, it raises strength limit and yield point and also raises hardness and abrasion resistance of steel. It is very important that tungsten has good influence on high temperature mechanical properties of steel to improve heat resistance and tempering stability of steel.

2. Chemical Compositions (GB/T3648-1996)

Chemical Compositions (%)W C P S Si MN Cu As Bi PB SB SN

≤ FeW80-A 75.0-85.0 0.10 0.03 0.06 0.5 0.25 0.10 0.06 0.05 0.05 0.05 0.06

Usage: It is applicable to act as the tungsten additive in steel smelting or alloy materials.

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Ferro Tungsten (FeW) Powder Typical Applications:

1) Powder metallurgy, Rare earth (RE) products, fabricating superalloys

2) Ferro tungsten is used in the production of high speed steels and tool steels, which refers to their ability to cut metals at high speeds. 

Ferro Tungsten (FeW) Powder Packaging:

Drums, Pallet boxes, Loose bulk

Ferro Tungsten (FeW) TSCA (SARA Title III) Status:

Listed. For further information please call the E.P.A. at +1.202.554.1404

Ferro Tungsten (FeW) CAS Number:

1) CAS# 7440-33-7 (Tungsten)

2) CAS# 7439-89-6 (Iron)

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Drill bits are cutting tools used to create cylindrical holes, almost always of circular cross-section. Drill bits come in many sizes and have many uses. Bits are usually connected to a mechanism, often simply referred to as a drill, which rotates them and provides torque and axial force to create the hole.

The shank is the part of the drill bit grasped by the chuck of a drill. The cutting edges of the drill bit are at one end, and the shank is at the other.

Drill bits come in standard sizes, described in the drill bit sizes article. A comprehensive drill bit and tap size chartlists metric and imperial sized drill bits alongside the required screw tap sizes.

Exceptionally, specially-shaped bits can cut holes of non-circular cross-section.

The term drill may refer to either a drilling machine or a drill bit for use in a drilling machine. In this article, for clarity, drill bit or bit is used throughout to refer to a bit for use in a drilling machine, and drill refers always to a drilling machine.

Many different materials are used for or on drill bits, depending on the required application. Many hard materials, such as carbides, are much more brittle than steel, and are far more subject to breaking, particularly if the drill is not held at a very constant angle to the workpiece; e.g., when hand-held.

Tungsten carbide and other carbides are extremely hard, and can drill virtually all materials while holding an edge longer than other bits. The material is expensive and much more brittle than steels; consequently they are mainly used for drill bit tips, small pieces of hard material fixed or brazed onto the tip of a bit made of less hard metal. However, it is becoming common in job shops to use solid carbide bits. In very small sizes it is difficult to fit carbide tips; in some industries, most notably PCB manufacturing, requiring many holes with diameters less than 1 mm, solid carbide bits are used.

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Ferro Tungsten (FeW) Chemical Properties Available:

1) Usual Grades and Nominal Chemical Composition

2) Standard chemistry:

W= 74-80%  C= 0.25% max  Si= 1% max  Mn= 0.5% max

Ferro Tungsten (FeW) Powder Physical Properties Available:

Lumps, pieces, granules & powder 

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