The rolling mill roll is mainly composed of a roll body, a roll neck, and a shaft head. The roll body is the middle part of the rolling mill roll that actually participates in the rolling of the metal. It has a smooth cylindrical or grooved surface. The roll neck is mounted in the bearing and the rolling force is transmitted to the frame through the bearing housing and the pressing device. The transmission end shaft head is connected to the gear base through the connecting shaft and transmits the rotational torque of the motor to the roller. The rolls can be arranged in the form of two rolls, three rolls, four rolls or multiple rolls in the rolling mill stand.
Rolling Mill Roll Types
There are many ways to classify rolls, including:
(1) According to product type, there are strip roll, section roll, and wire roll.
(2) According to the position of rolls in the rolling mill series, there are blanking rolls, roughing rolls, finishing rolls, etc. (3) According to the roll function, there is scale breaking roll, piercing roll, flattening roll, etc.
(4) According to the material of rolls, there are steel rolls, cast iron rolls, carbide rolls, ceramic rolls, etc.
(5) According to the manufacturing method, there are casting roll, forging roll, surfacing roll, inlaid roll, etc.
(6) According to the state of rolled steel, there are hot rolls and cold rolls.
Various classifications can be combined to give a clearer meaning to rolls, such as centrifugally cast high chromium cast iron work rolls for hot strip rolling
The performance and quality of rolls are generally determined by their chemical composition and manufacturing methods and can be evaluated by their structure, physical and mechanical properties, as well as the types of residual stresses existing in the rolls (see Roll Inspection). The use effect of rolls in rolling mills depends not only on the material quality and metallurgical quality of rolls but also on the use conditions, roll design, operation, and maintenance.
There are great differences in roll service conditions of different types of rolling mills, which are caused by the following factors:
(1) Rolling mill conditions. Such as rolling mill type, rolling mill, and roll design, pass design, water cooling conditions, and bearing types, etc.
(2) Rolling conditions. Such as rolling varieties, specifications and deformation resistance, reduction system and temperature system, production requirements and operation, etc.
(3) Requirements for product quality and surface quality.
Material and Use Table of Common Rollers
Roller neck tensile
High chromium steel
Tool steel (high carbon)
Large and medium section billet and roughing mill stand, strip mill roughing mill stand, backup roll
Large, medium and small section steel intermediate and finishing mill stand, strip work roll
Large, medium and small section roughing mill
Strip roughing rear frame, finishing front frame,
cold rolling strip work roll
Hot Strip Finishing Mill Stand, Small or Wire
Finishing Mill Stand
Chilled cast iron
Unbounded (Limited) Chilled Cast Iron
High chromium cast iron
Special cast iron
Finishing Mill Stand for Plate, Wire, Profile, and
Medium-rolling and finishing mill stand for
sheet, wire, profile, and pipe, and finishing mill
stand for strip and plate
Rough and medium mill stand for profiles, wires,
Finishing mill stand for a small section and wire
and strip pre-finishing mill stand
Precision rolling and finishing rolling of small,
wire and pipe
Small, wire rod finishing mill stand, cold rolled small steel
Small, wire finishing mill stand, strip finishing mill stand
Forged semi-steel and white iron
Opening, large roughing mill stand, Plate
Roughing mill stand
Cold rolled strip work roll, profile and welded
pipe forming roll
Cold and Hot Strip Mill
Large, Medium and Small Rough, Medium and
Finishing Mill Stands
Note: Composite roll neck material is selected according to strength requirements.
Therefore, different types of rolling mills and rolling mills with different operating conditions have different requirements for the performance of the roll, such as square billet and slab blooming mill rolls with good torsional and bending strength, toughness, biting, thermal cracking resistance, thermal shock resistance and wear resistance. The hot strip finishing mill stand requires high hardness, indentation resistance, wear resistance, spalling resistance and heat cracking resistance of roll surface.