Tungsten Dart Billet,Tungsten Dart Price

Properties Of Cemented Tungsten Carbide

Details: Category: Tungsten Information; Published on Monday, 29 July 2013 13:55; Written by Yuri; Hits: 2142

A cemented carbide is a composite material comprised of individual tungsten carbide grains imbedded in a ductile metal binder matrix of either cobalt or nickel. The physical and metallurgical properties of a particular “grade” of carbide are determined by its composition (its constituents and their relative amounts), the size distribution of the tungsten carbide grains after sintering, the binder metal type and content, the quality of the raw materials used, and the workmanship with which the material is made. Those most commonly measured to assess quality and define application areas are described below. The ASTM and/or ISO standard that applies to each of these measurements is also noted.

Density or specific gravity is the weight per unit volume of a cemented carbide measured in grams per cubic centimeter (g/cm3). It is essentially the weighted average of the densities of all of the components contained in the product and is therefore a check on its composition. For grades containing only tungsten carbide and a binder metal, the density of the composite decreases as the lighter binder metal content increases.

Hardness is the resistance of a cemented carbide to penetration by a diamond indenter under a specific load. It is measured on the Rockwell A (Ra) scale in the US and on the Vickers (HV10 or HV30) scale in Europe and elsewhere. Hardness is primarily a function of composition and grain size with higher binder metal contents and coarser tungsten carbide grain sizes producing lower hardness values. Conversely, low binder contents and fine grain sizes produce high hardness values. Hardness is directly related to abrasive wear resistance.

Transverse Rupture Strength (TRS) is a measure of the tensile strength of a cemented carbide in a three point bending test performed on standard rectangular bars. It is reported in units of pounds or thousands of pounds per square inch (psi or kpsi), or in Newtons per square millimeter (N/mm2). TRS is perhaps the best measure of the relative utility of individual production batches since it surveys a reasonable volume of material and will detect low levels of critical internal defects. Products having relatively high TRS values are generally applied where shock, impact, or failure by breakage are factors.

Residual Porosity is determined by visually examining the polished surface of a sintered sample at 100X or 200X magnification. Ratings for “A” type porosity (pores less than 10 microns in diameter), “B” type porosity (pores larger than 10 microns in diameter), and “C” type porosity (carbon inclusions) are determined by comparing the size and frequencies of each pore type in the sample with those in standard photographs. Each standard photograph is associated with a numerical rating that is used to represent the porosity levels in the sample. In general, edge strength and toughness decrease as the level of residual porosity increases. At high levels of porosity, the wear resistance of the product may also be adversely affected.

Magnetic Saturation is the degree to which the metal binder in a cemented carbide is saturated with carbon. It is most useful for materials having a cobalt binder. For a known cobalt content magnetic saturation values indicate how much carbon the cemented carbide contains – from unacceptably low values that indicate the presence of an undesirable carbon-deficient phase (known as eta phase) to unacceptably high values indicating the presence of free carbon (carbon “porosity”) in the product. Magnetic saturation is sometimes used as an indicator of relative strength among lots of a specific grade.

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com

Gradient Cemented Carbides

Details: Category: Tungsten Information; Published on Friday, 26 July 2013 13:57; Written by Yuri; Hits: 2014

Gradient cemented carbides allow tailoring important properties such as stiffness and toughness in a single hardmetal component in different areas such as skin and core. Established gradients in the cemented carbide industry are the so-called γ-phase-free gradients for metal cutting applications and macro-gradients for rock tools applications . However R&D publications on development of γ-phase-free gradients in cemented carbides have become fewer over the last decade. A reasonable explanation is the increased focus on the development of novel CVD and PVD coatings for machining applications, especially relating to coating composition, nanostructure, adjustment of texture, residual stress, post treatment processes and bonding between layers and layer to substrates and more.

Computational thermodynamics has been successfully applied to model the kinetics of gradient formation in both Co-based cemented carbides. Good agreement between experiment and simulation regarding layer thickness, phase fraction distribution and element profiles was obtained on DICTRA modelling of gradient formation kinetics considering that all diffusion occurred in the liquid binder phase of a dispersed system model for example in Ni-based cemented carbides.

Nitridation of cemented carbides and cermets has once again been resurrected by various research schools in order to generate gradients that show superior wear properties in metal machining.

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com

Tungsten Alloy Subprojectile for AHEAD

Details: Category: Tungsten Information; Published on Friday, 26 July 2013 10:04; Hits: 2077

The 35mm by 228mm AHEAD ammunition is an original cartridge type, programmed detonator ammunition, composed of a Programmable Fuze System, tungsten alloy subprojectiles, ejection standoff ammunition, a thin-walled body, nitrified fibre firing ammunition and steel ammunition cartridge. This tungsten military defense is become more and more widely used in the military field.

In the anti-missile role it uses Advanced Hit Efficiency And Destruction (AHEAD) ammunition. This round ejects 152 tungsten projectiles at a predetermined distance, between 40 and 10 m, from the target. A 25-round burst of AHEAD rounds produces 3,800 of these small projectiles to destroy the incoming missile. Cruise missiles can be destroyed at 2.5 km and high speed missiles at 1.5 km range by tungsten military defense. A more common projectile to see in service is the advanced hit efficiency and destruction [AHEAD] round. Given the size of the diameter and the larger length of the projectile, as opposed to a 35mm AHEAD round, more tungsten alloy subprojectiles are carried - one hundred and eighty as opposed to one hundred and fifty-two . The submunitions of this tungsten military defense are tungsten-alloy [WHA] spheres, designed for both penetration and 'mass effect', to increase the likelihood of engaging the incoming 'vampire' or 'bogie'. The round is termed the MCP170 and uses a programmable magnetic fuze which uses information provided by the coil velocity gauge near the gun's muzzle in order to automatically compute the correct estimated time to target.

The combat efficiency of the AHEAD ammunition is due to the payload of 152 tungsten alloy subprojectiles weighing 3.3 grams each. These subprojectiles are activated at a certain distance in front of the intercepted target, forming a mass of lethal subprojectiles, greatly augmenting the probability of a kill. The tungsten alloy subprojectiles have a sharp edge, ensuring that this tungsten military defense can inroad into the target with precise accuracy, tungsten military defense also provides the kinetic energy to destroy the electrical components, payloads or motor of the target.

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com

About Tungsten Carbide Tips

Details: Category: Tungsten Information; Published on Friday, 26 July 2013 13:47; Written by Yuri; Hits: 1765

Carbide (Or rather called Tungsten Carbide and Titanium Carbide) is normal materials which are widely used for any kinds of cutting tools. For example: Saw Blades, Lathe Tools, Drill, Turning and Milling Tools and Dental Bits are always made from Carbide Materials. Carbide is widely used at these tools because carbide's wear-resistant, sharper and useful time is longer than other materials. In additional, carbide balls are also used in pen tips, because it is more wear-resistant.

Like tools of tungsten carbide saw blades, its main body is made from Steel. Tungsten carbide tips are brazed on the saw blades. Fine-quality tungsten carbide tips is excellent wear-resistant, its useful time can up to 20 times than Steel tips.

Tungsten carbide tips has turned in the last, but you can re-grind them just like you grind steel tools, but tungsten carbide tips is harder, so grinding tools is different. Normally, we use diamond tools or tungsten carbide grinding wheels.

Most of the whole tools are not made from carbide, because carbide's price is very expensive and it is very brittle. So, steel is better materials which are used for making main body, it is more stronger, not easy to crack and broken.

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com

Tungsten Alloy Shielding for Nuclear Scale

Details: Category: Tungsten Information; Published on Thursday, 25 July 2013 11:19; Hits: 1917

Tungsten alloy shielding is necessary for nuclear scale. Nuclear scale utilizes rays which released by radioactive isotope and absorbed partially or scattered to realize quantification when rays pass through matters. Nuclear scale is used to measure the matters in transport system. Radioactive source and receiver are located on the upper side and downside of conveyer belt. According to counting rate that rays pass through matters, nuclear scale can weigh the amount of matter in delivering constantly. More regular and even sizes of matters are, the higher accuracy is. Nuclear scale is primary used for measuring dynamic matters. It has been widely used in building materials, coal, chemical industry or other industries. It can be also used for various kinds of conveyor such as scraper, screwing and anchor chain.

The radioactive sources of nuclear scale are ⁶⁰Co and ¹³⁷Cs.

Tungsten alloy shielding for nuclear scale can protect staffs from radiation. The density of tungsten alloy is higher twice than lead. The high density allows a reduction in sized of shielding components without compromising effectiveness of shielding characteristics. Otherwise tungsten alloy has the advantage of non-toxicity.

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com