Tungsten carbide roll rings have high hardness and its hardness variation with temperature is very small. Hardness value is four times of high speed steel at 700 ℃. But the elastic modulus, compressive strength, flexural strength and thermal conductivity are all higher than the tool steel more than one times. The hard alloy roll has high thermal conductivity, so the cooling effect is good. Hard alloy roll are more resistant to corrosion and thermal fatigue resistance than the tool steel roller.
Tungsten carbide roll rings have many advantages. Firstly they can improve the quality of steel products and make the surface quality and dimensional tolerances improved thoroughly. Secondly they can reduce replace times and down time. Certainly they can reduce the scrap rate and the labor intensity of the production workshop. Finally reduce the cost is an effective way for enterprises to increase.
However tungsten carbide roll rings have high sensitivity to crack and unable to withstand cold and hot with high hardness and big brittleness. Otherwise it easily to lead destructive accidents.
Tungsten carbide balls can made for shotgun cartridges. The shotgun cartridge is not same as ordinary cartridge. It is a ball full of something. The bullet is dispersed into many small balls when shoot from gun muzzle. Explosive power is acting on each balls. Every ball has lower energy. In the hunting activities, people are usually main for shooting birds or other small animals.
Mill ball produces amounts and relative sliding after it has loaded. The connect surface temperature of mill ball parts become rise and oxidation also become more quickly. From the test, we all know that the release energy in the process of fretting wear has been mostly used up with heating. Fretting wear area of mill steel ball often appear fatigue crack. But the contact stress is only produced in the shallow surface of the ball. And generally speaking, these crackles will no longer extension.
Fretting wear of the steel ball mill is difficult to eliminate completely. However take proper measures can reduce the wear degree. Such as reduce the fretting contact area, mill ball change to the whole structure, some of connect surface hardening, improve the ball tube finish, spray hard metal on the surface, improve the mill steel ball contact stress or increase the friction between the contact surfaces. Adding the material with high elastic strain limit can uptake fretting amplitude. This can prevent the ball tube fretting wear.
