This document outlines the technical considerations relevant to the use of ISO L-HM hydraulic oils in industrial hydraulic systems. It is intended to support engineering, maintenance and procurement teams when assessing hydraulic oil suitability within existing operating and approval frameworks.
Equipment covered
- Machine tools and presses
- Material handling systems
- Automated production equipment
Key operating risks addressed
- Pump and valve wear under continuous operation
- Loss of pressure or control stability
- Thermal stress during sustained duty cycles
Hydraulic oil technical basis
Industrial hydraulic systems typically operate under continuous or near-continuous duty and require consistent viscosity performance, defined antiwear protection and resistance to thermal degradation. Hydraulic oils used in these applications are commonly aligned with ISO 11158 L-HM and DIN 51524 Part 2 performance categories.
Hydraulic viscosity grade selection
| System condition | Typical viscosity grade | Selection rationale |
|---|---|---|
| High speed systems or low ambient temperatures | ISO VG 32 | Supports improved flow characteristics and responsive system control |
| General industrial hydraulic duty | ISO VG 46 | Provides balanced wear protection, thermal stability and efficiency |
| High load or elevated operating temperatures | ISO VG 68 | Improves film strength and component protection under sustained stress |
Equivalency and approval position
Hydraulic oils aligned with ISO 11158 L-HM or DIN 51524 Part 2 are generally considered technically suitable for industrial hydraulic systems when viscosity grades are selected in line with equipment manufacturer guidance and operating conditions.
Changeover guidance
- Changeover is typically carried out during planned maintenance activities
- System flushing is not normally required when replacing lubricants of the same specification category