Optimizing 6-Hi Leveler Machines: The Ultimate Guide to Bronze Flange Self-Lubricating Bushes

In the metal processing industry, the 6-Hi Leveler Machine is a crucial piece of equipment used to achieve perfect flatness in high-strength metal sheets and heavy plates. However, the extreme radial loads, continuous vibration, and strict requirements for sheet surface cleanliness present a massive challenge for traditional roller bearings and lubricated bushings.

The most reliable engineering solution for these harsh operating conditions is the Bronze Material Flange Type Self-Lubricating Bush (often referred to as an oilless flanged bearing).

In this article, we will explore the specific application locations of these flanged bushes within a 6-Hi leveler and detail the optimal material selection to ensure maximum durability and precision.

Why Choose a “Flange Type” Self-Lubricating Bush?

Before diving into specific locations, it is vital to understand why the flange type is superior to a standard straight cylindrical bush.

In a 6-Hi leveler, the compact arrangement of work rolls, intermediate rolls, and backup rolls leaves limited space. A flanged bearing is a “two-in-one” solution:

1. The cylindrical body absorbs massive radial loads (the pressing force).

2. The flange face acts as a built-in thrust washer, absorbing axial loads and preventing the bush from being extruded or shifting out of its housing due to heavy machine vibration.

Key Application Locations in a 6-Hi Leveler Machine

To ensure smooth, maintenance-free operation, flange-type self-lubricating bushes are strategically installed in the following critical zones:

1. Backup Roll Bearing Housings (End Supports)

The backup rolls bear the vast majority of the pressure required to flatten the metal sheet. During operation, these rolls experience micro-axial movements. The flanged bronze bush perfectly handles the extreme radial pressure while the flanged edge absorbs the axial thrust, preventing metal-to-metal friction without the need for constant greasing.

2. Screw-Down & Tilting Mechanisms

Used to adjust the roll gap and the tilt of the leveler, these mechanisms operate under extremely high static loads at very low speeds. Traditional lubricated bearings often suffer from “stick-slip” in these conditions. The solid lubricants in the bronze bush ensure smooth, high-precision adjustments, allowing the leveling gaps to be set accurately.

3. Roll Bending Mechanisms (Hydraulic Clevis & Pins)

To correct center buckles or edge waves in the metal, 6-Hi levelers use bending mechanisms to alter roll deflection. The joints and hinge pins in these mechanisms operate with small oscillating angles under massive stress. The flanged oilless bushing prevents axial shifting of the pin while handling the high-stress oscillations flawlessly.

4. Side Guide Rollers & Pinch Rolls

At the entry and exit points of the leveler, guide rollers experience continuous impacts and axial forces from the edges of the metal plates. Flange-type bushes provide excellent shock resistance and reliable axial positioning for these guiding systems.

Material Selection: Engineered for Heavy Duty

For the demanding environment of a 6-Hi Leveler—characterized by heavy loads, low speeds, and the presence of iron oxide scale—standard bronze is not enough. The bush must be manufactured from a high-strength base metal embedded with specially formulated solid lubricants.

1. The Base Material: High-Tensile Brass (CuZn25Al5Mn4Fe3)

For leveling equipment, High-Tensile Brass (often cast as JDB-1) is the gold standard.

• Exceptional Load Capacity: It offers extreme yield strength and compressive strength, capable of withstanding static loads up to 250 N/mm² and dynamic loads up to 100 N/mm². This ensures the bearing will not deform plastically under the crushing force of the leveler.

• (Alternative): If the leveler operates in a highly corrosive environment (e.g., using heavy cutting fluids or emulsions), Aluminum Bronze can be selected as the base material for superior corrosion resistance.

2. The Solid Lubricant Plugs: Graphite + PTFE/MoS2

The inner diameter and the flange friction face are machined with holes and embedded with solid lubricant plugs.

• How it works: As friction occurs, the solid lubricant releases and coats the mating shaft, creating a thin, highly durable solid lubrication film.

• The “Clean” Advantage: Because these bushes operate completely dry (oilless), there is zero risk of grease or oil dripping onto the metal sheets. Furthermore, unlike wet grease which attracts iron dust and acts as an abrasive, the dry lubricating film remains unaffected by factory dust and oxide scales.

Conclusion

Upgrading your 6-Hi Leveler Machine with Bronze Material Flange Type Self-Lubricating Bushes is a strategic move to reduce maintenance downtime, eliminate sheet contamination from oil leaks, and ensure long-term, high-precision leveling.

When specifying your bearings, always ensure that both the inner cylinder and the flange face are embedded with solid lubricants to handle the complex radial and axial forces of metal forming machinery.

Looking for Custom Self-Lubricating Bearings for Your Rolling Mill or Leveler?
viiplus.com specializes in manufacturing high-tensile bronze flange bushes tailored for heavy-duty metalworking equipment. Contact our engineering team today for a quote and technical support!