Hydraulic power units in metallurgical lines operate under some of the most demanding industrial conditions.
High pressure, continuous duty, heavy contamination and frequent shock loads define their working environment.

Applications such as continuous casting segment reduction, shearing operations and coiler tension control require hydraulic systems to operate for long periods at 25–31.5 MPa, while also handling repeated impacts and start-stop cycles.

Industry Background

Many existing production lines were originally equipped with piston pumps or conventional external gear pumps.
As these systems age and are upgraded with variable-frequency or servo drives, several limitations become increasingly evident:

Internal leakage rises under sustained high pressure, making it difficult to reach setpoints without increasing relief pressure

Pressure fluctuation becomes more pronounced during impact loads, affecting cutting quality and coiler tension stability

High sensitivity to oil cleanliness leads to wear, scoring or sticking when filtration is not consistently maintained

These issues reduce system efficiency and increase unplanned maintenance.

Core Requirement

Metallurgical hydraulic systems require:

Stable pressure output under long-term high load

Controlled response during shock and impact conditions

Tolerance to contamination in real operating environments

Reliable performance with predictable maintenance intervals

Solution Approach: FG Series High-Pressure Internal Gear Pumps

To meet these requirements, more new installations and retrofit projects are adopting FG internal gear pumps as the main hydraulic power source.

Key Technical Parameters

Rated pressure up to 31.5 MPa
Maximum pressure up to 35 MPa

Displacement range from FG1 25–63.7 mL/r to FG2 64.7–162.8 mL/r

Speed range from 200 to 3000 r/min

These specifications cover both distributed hydraulic systems and large centralized stations.

Structural Advantages

Internal gear design provides low pulsation, improving stability under impact loads

Robust structure reduces sensitivity to oil contamination

Stable volumetric efficiency across a wide operating range

With reasonable filtration, FG pumps maintain long service life in high-temperature, dusty environments

System Design Strategy

In modern metallurgical hydraulic stations, engineers often adopt a structured configuration:

A large-displacement FG2 pump is used as the main high-pressure source for primary cylinders

Auxiliary circuits such as lubrication, clamping and secondary actuators are supplied by FG21 dual pumps or mid-range FG1 pumps

This approach simplifies system layout while maintaining separation between main and auxiliary functions

It also reduces overall noise and avoids the strict cleanliness requirements typical of piston pump systems

Performance Improvements in Operation

Field experience shows several consistent improvements after adopting FG pumps:

High-pressure segments maintain more stable output, reducing the need for overcompensation

Pressure drop during shearing and impact loads is minimized

Actuator response becomes more stable and predictable

Unplanned pump-related downtime decreases, improving overall system availability

Maintenance teams can shift from reactive repairs to scheduled maintenance

Engineering Value

FG internal gear pumps provide a balanced solution for metallurgical applications by combining:

High-pressure capability for continuous heavy-duty operation

Tolerance to contamination in harsh environments

Stable performance under shock loads

Reduced maintenance complexity

Summary

For metallurgical hydraulic systems, reliability depends on aligning pump performance with real operating conditions rather than ideal assumptions.

FG internal gear pumps enable:

Stable high-pressure operation

Improved resistance to contamination

Reduced fluctuation under impact loads

More predictable maintenance and lower downtime risk

This makes them a practical and scalable solution for both new metallurgical lines and retrofit projects.