In addition to the conventional mechanical properties, various rolling mills have put forward a series of special requirements for the performance of the rolls, which are different from other products.
1. Fracture resistance. The ability of roll body and roll neck to withstand working stress without transverse fracture. For the specific conditions of use, the main thing is that it should have sufficient strength and toughness, and there should be no manufacturing defects that may cause fracture.
2. Wear resistance. The ability of the working part of the roll body to resist weight loss or size reduction during the rolling process. It should be noted that the wear resistance of the roll in the hot state and the wear resistance in the cold state are not necessarily the same. The relatively good wear resistance of a roll in the cold state does not mean that it has good relative wear resistance in the hot state, and vice versa. The wear mechanisms of the work rolls coexist in various types, including rolling friction, sliding friction caused by plastic deformation of the rolled material, and abrasive wear caused by scale.
3. Anti-peeling. The ability of the roll to not cause the roll body to fall off under the long-term contact stress.
4. Thermal cracking resistance. The work rolls for hot rolling are subjected to thermal fatigue caused by the shock and heat from the rolled material and cooling liquid, and the ability to resist this effect without producing network cracks or making the network cracks thinner and shallower.
5. Thermal shock resistance. When the work roll bites into the hot billet, the temperature of the roll surface rises rapidly locally or due to friction when the steel is jammed. The ability to resist this thermal shock without cracks and peeling off is called thermal shock resistance. An important indicator of the performance of work rolls.
In addition, there are roughness resistance, bite resistance, etc. For a specific roll of a specific rolling mill, its performance requirements will be emphasized, and sometimes several properties are required.
It needs to be clearly pointed out that the various performances mentioned above are all for specific working conditions, so they are all relative concepts.