Bearing seat for transfer side working roll of hot rolling mill

Bearing seat for transfer side working roll of hot rolling mill

The Hot Rolling Mill Drive Side Work Roll Bearing Seat is one of the key precision components used in hot rolling mill equipment. Installed on the drive side of the work roll, the bearing seat provides stable bearing support and positioning while transferring mechanical loads between the work roll assembly and the mill structure.

In addition to supporting the work roll bearing, the drive-side bearing seat is part of the rolling mill power transmission system. It works with the main drive arrangement to transmit torque to the work roll. The supplied application data indicates that peak torque can reach approximately 500 kN·m, while rolling forces can reach approximately 2000–6000 kN on one side depending on the mill configuration.

The bearing seat also needs to maintain the required work roll positioning accuracy during operation. The specified work roll radial runout requirement can be as low as 0.04 mm for applications requiring strip thickness tolerance of approximately ±0.15%.

Operating Conditions

The bearing seat operates under demanding hot rolling conditions. The bearing position working temperature is specified at approximately 80–120°C, with instantaneous peaks of up to 180°C under certain operating conditions. Rolling speed can reach 15 m/s, with higher speeds of up to 20 m/s possible in configurations using oil-film bearings.

Work rolls may need to be replaced at least once per shift, making efficient disassembly and maintenance an important consideration in the bearing seat design. The component therefore needs to combine structural strength, dimensional accuracy, and practical maintenance requirements.

Repeated rolling loads and impact loads also require the bearing seat to maintain stable mechanical performance during continuous operation.

Material and Heat Treatment

The main material specified for the work roll bearing seat is ZG35CrNiMoV special-grade cast steel. The supplied chemical composition range includes C 0.33–0.37%, Cr 1.0–1.3%, Ni 1.2–1.6%, Mo 0.3–0.5%, and V 0.15–0.25%.

The material is specified for applications requiring strength and fatigue resistance under demanding rolling conditions. The supplied reference data indicates a yield strength of at least 650 MPa at 300°C and a fatigue-life reference of Nf ≥ 2 × 10⁶ cycles at Δσ = 400 MPa.

The work roll bearing seat body can receive quenching and tempering followed by aging, with a reference hardness of HB 300–330. Different functional components can use different materials and treatments. For example, the torque-transmission keyway can use 42CrMoA with nitriding treatment, while the sealed end cap can use duplex stainless steel 2205 with solution treatment.

The final material and heat-treatment requirements are determined according to the product drawing and customer specification.

Surface Strengthening

Critical surfaces of the bearing seat can receive additional surface treatment according to the application requirements.

For the bearing hole, the supplied process includes HVOF WC-12Co coating, with a reference coating thickness of 150–200 μm and hardness of HV ≥1300. This type of surface treatment can be applied where improved wear resistance is required at the bearing-related functional surface.

The sealing surface can receive laser hardening, with a reference hardened layer depth of 1.2–1.5 mm and hardness of HRC ≥52.

The actual surface treatment process is selected according to the material, surface function, operating environment, and customer technical requirements.

CNC Machining Process

GW Precision has established a structured machining process for large rolling mill precision components.

During the first vertical machining center operation, the component is machined according to the drawing geometry, with appropriate machining allowance reserved on the relevant surfaces. The machined area is cleaned, burrs and sharp edges are removed, and the first piece is inspected before continuing production.

The horizontal boring machine is then used for relevant holes, grooves, and surfaces. Reference machining allowances are retained according to the supplied process requirements, including approximately 1.5–2 mm on selected surfaces and grooves and 3–4 mm for certain hole operations.

A subsequent vertical machining operation performs finish milling and boring according to the specified dimensions and tolerances. The process is arranged to control dimensional accuracy and geometric tolerances of the bearing seat.

Bench-work operations are used for thread bottom holes, positioning holes, oil holes, and screw holes. After drilling and tapping, the component is cleaned and inspected.

The final inspection stage includes cleaning, removal of sharp burrs, and submission of the finished bearing seat for inspection.

Inspection and Quality Control

Quality inspection covers material verification, non-destructive testing, performance testing, and dynamic inspection according to the specified requirements.

For material inspection, chemical composition can be verified using an ICP spectrometer, with the supplied reference requirement of element deviation within ±0.01%.

Non-destructive testing includes ultrasonic testing according to EN 12680-3 Class 1 and magnetic particle inspection according to ASTM E709. These inspections help identify internal or surface discontinuities in critical components.

The supplied testing specifications also include static load testing, dynamic fatigue testing, and sealing performance testing. Where applicable, the reference requirements include 1.8 times rated load without deformation, 10⁷ fatigue cycles without cracks, and 0.6 MPa pressure holding without leakage.

Dynamic inspection can include G0.4 dynamic balance according to ISO 1940-1 and vibration intensity of ≤2.5 mm/s according to GB/T 29531.

GW Precision can manufacture the Hot Rolling Mill Drive Side Work Roll Bearing Seat according to customer drawings, material specifications, machining requirements, inspection standards, and application conditions.

Customized Manufacturing

The structure of a work roll bearing seat varies according to the hot rolling mill configuration, work roll dimensions, bearing arrangement, drive system, and maintenance requirements. GW Precision therefore supports customized manufacturing based on customer drawings and technical specifications.

Customers can specify different material requirements according to the application. The machining process, heat treatment, surface strengthening, inspection method, and packaging can also be arranged according to the product specification.

For export orders, the finished bearing seat can be packed in wooden cases according to transportation requirements. Sea transportation is available, with Shanghai Port provided as the reference nearest port in the supplied information. Delivery time depends on order quantity and production requirements.

Through controlled material selection, heat treatment, precision CNC machining, surface treatment, and multi-stage inspection, GW Precision provides customized work roll bearing seat manufacturing for hot rolling mill applications.

FAQ

1. Can You Make This Bearing Seat for The Working Roll Product According To The Customer's Requirement?

A: Yes, we can follow your specific requirements.

2. Can I Visit Your Factory Before We Ordering ？

A: Yes, welcome to our factory for field trip.

3. Where Is The Nearest Port To You Company?

A: Shanghai port is the nearest one.

4. Can We Choose Different Materials for the bearing seat for the working roll ?

A: Yes, it can be selected depend on your requirements.

5. How Long will It Take And Deliver To Me For the Bearing Seat for The Work Roll?

A: It usually takes one and a half to two months by sea. It depends on the quantity of your order.

6. What Is Your Cover Of The Package?

A: We use wooden box to export.

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