What are the characteristics of the work of the roll and how to classify according to the hardness value

Roll is one of the most important parts of the mill, the rolled parts through the rotation of the roll to produce plastic deformation, rolled to meet the requirements of the shape and dimensional accuracy of the product, the other parts of the mill are for the installation, support, adjustment, replacement of rolls and guide the rolled parts correctly in and out of the rolls and the settings. Rolls are composed of roll bodies, roll necks and shaft heads. The roll neck is mounted in the bearing and transmits the rolling force to the frame through the bearing seat and the press-down device. The shaft head is connected to the connecting shaft to transmit the rolling torque. Shaft head has plum blossom shaft head, universal shaft head, with keyway or cylindrical shaft head and other three main forms.

1. Roll work is characterized by: roll in the rolling process, directly or indirectly and rolling contact, forcing the rolled parts to produce plastic deformation, so bear a lot of rolling pressure, rolling torque and dynamic load. Especially when hot rolling, due to the high temperature of the rolled parts, the rolls cooled with coolant, the working conditions are extremely poor, so the strength of the rolls, stiffness, toughness, surface hardness, abrasion resistance, roll shape have strict requirements to ensure that the quality of the rolled parts and yield.
2. Rolls can be divided into according to its hardness value:
(1) soft roll. Shaw’s hardness of about 30-40, used for open billet machine, large section steel mill roughing mill, etc..
(2) semi-hard roll. Shore hardness of about 40-60, for large, medium, small steel mill and plate mill roughing mill.

(3) hard surface rolls. Shore hardness of about 60-85, for thin plate, plate, medium-sized steel and small steel mill roughing mill and four-roll mill support roll.
(4) Special hard rolls. Shore hardness of about 85-100, for cold rolling mill.

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