In part 6 we know that catering failure happens when the tungsten carbide cutter’s surfaces are stricken by particulate-bearing liquid or gas, especially when the operating temperatures are much higher and the more fine-grained the carbide is, the easier for the failure to occur.. In this part we will talk about adhesion wear/galling as another failure mode.

7. Adhesion wear/galling 

Adhesion wear occurs when a tungsten carbide cutter’s surface and that of a mating part or the work material rub together or slide past each other with sufficient force to create excessive friction and pressure at high points of contact between the materials. The high temperatures and pressures generated in these contact zones result in plastic deformation at the material surfaces, penetration of one surface by the high points on the other, and finally the transfer of material (welding) of one material to the other. As material builds up on one of the surfaces, the still higher points of contact create more heat, leading to more deformation, penetration, and material transfer. This process is often referred to as “galling”. Failure by adhesion wear can take several forms, but typically the buildup reaches a stage where it eventually is dislodged pulling chunks of the carbide surface with it.

 (To be continued. This article is divided into 9 parts and this is part 7, for part 6 please refer to http://news.chinatungsten.com/en/tungsten-information/79384-ti-10152)

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
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The tungsten-based bucking bar has one or more smooth surface which is held up against the back of a rivet while it is being shot. The energy gets transferred from the source (the rivet gun) through a medium (the rivet) to the receiver (the bucking bar). The gun is on one end, and the bucking bar is on the other. The gun impacts the rivet, which sends the impulse to the bucking bar, which actually bounces off the rivet and "swings" back at it (by virtue of the person holding it firmly in place), smashing the rivet in turn. This happens many times per second - depending on air pressure and trigger operation. The primary skill required when bucking rivets is to hold the bucking bar stable and square to the rivet. Other than that, just let physics do the work. You don’t have to push on the rivet, just hold it steady.

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
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In part 5 we know that although carbide material is hard, tungsten carbide cutters can still deform plastically due to a high enough temperature to soften the binder metal, and such a tiny thermal deformation can result in the function failure of assembly tools. In this part we will talk about cracking which is also one of the most common failure modes of tungsten carbide cutters.

6. Cratering failure

Failure known as “cratering” is a localized form of erosion in which a depression develops at the point where a continuous stream of metal or particulate-bearing liquid or gas strikes the working surface of the tungsten carbide cutter’s component. At operating temperatures high enough to soften the binder metal (those exceeding about 900° C.) cratering can take place rapidly. Very fine-grained carbides are particularly susceptible to cratering since smaller grains are locked into the carbide surface by a relatively thin layer of binder metal. As the crater increases in size and depth the carbide is weakened to the point where normal operating stresses produce mechanical failure in the area of the crater.

(To be continued. This article is divided into 9 parts and this is part 6, for part 5 please refer to http://news.chinatungsten.com/en/tungsten-information/79348-ti-10146 ; for part 7 please refer to http://news.chinatungsten.com/en/tungsten-information/79387-ti-10153)

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email:sales@chinatungsten.com
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Tungsten alloy is a kind of composite materials that tungsten whose quality fraction is 80%-98% distributes to Ni-Fe-W sosoloid, as it is wished, tungsten alloy combines with the high density, high strength of tungsten and good ductility of matrix, so it has a series of properties of physics, chemistry and mechanics.

Tungsten alloy has wide usage in military industry with its good properties, one of applications is tungsten alloy anti-material rifle bullet, anti-material rifle continues the thinking of anti-tank rifle which was used in twice World War, it can launch large caliber machine gun bullet cooperating with anti-material rifle bullet, it can penetrate light tank which has thin armor, and kill personnel in the tank, it can also kill sniper hiding behind blindage mainly used for dealing with vehicles, oil depot, radar, telescopic surveillance mirror, copper flying at low altitude and jet landing on the ground. 

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
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