How to use Cemented Carbide Roll Rings

Attention should be paid as follows when purchasing and using cemented carbide roll ring:

1. Grades selection
An overall understanding of the properties of cemented carbide grades of is a basis for correctly selecting the grades for cemented carbide roll ring used in the stands of rolling mills and an optimal combination of grades is required for the various stands of rolling mills.

2. Roll rings installation
Steel-case mounting and assembly of cemented carbide roll ring should be strictly performed according to the precision required by design process. Proper fitting is needed for the cemented carbide roll ring, roll mandrel for stands and conical sleeves, which can not be over tight or loose. When it is too tight, the roll rings are in a tensile state and more fluctuation of rolling force will make the roll rings break. When it is too loose, it causes leads the roll rings, roll mandrel and conical sleeve to slide relatively during rolling, which scratches conical sleeves and roll mandrel so resulting in cracks. Before running the mills make a check if thecemented carbide roll ring meets the needs and roll ring. the assembling faces of the conical sleeve and the roll mandrel need to be cleaned. It is forbidden to knock at the roll rings with a hammer or other hard materials when running the mill. It is forbidden for the roll rings to impact each other during the transportation and installation to prevent roll rings from damage.

3. Cooling and cooling water quality
Cooling is intended to reduce the influence on roll rings, thermal corrosion, fatigue and stress during milling. It can prevent the roll rings from cracking and slow down the diffusion of cracks, prolonging the life time of grooves. It plays an important role in optimizing the performance of roll rings. The reference data for cooling are as follows: the temperature of cooling water is below 25 ° C; pressure of cooling water is 5-6 bar with a water volume of 24-30 m3 /hr/stand. The water is jetted in a radial direction and the angle between the water jet and the rotating direction of roll rings is 15-30 degrees. The width of the water column is 2 times that of the groove and the water should be jetted directly into the grooves and the water should not be scattering or misty.

4. Reasonable rolled quantity
During rolling microcracks in grooves can not be avoided, and they need to be reground when they are at a certain depth (normally controlled at 0.2mm). Excess rolling causes the depth of microcracks to extend rapidly and dangers of crushed rolls increases, which should be prevented.

5. Regrinding of grooves
Microcracks will occur after the rolling of the groove for some time and when the microcracks extend to 0.2mm the cemented carbide roll ring has to be reground. Microcracks must be reground thoroughly when regrinding, otherwise the unground microcracks will make the microcracks extend more rapidly during the next rolling and probably make the roll ring crack.