Overview
ISO 12151-4:2007 establishes the general and dimensional requirements for hose fittings with ISO 6149 metric stud ends intended for hydraulic fluid power and general use. It covers carbon-steel hose fittings for nominal hose inside diameters from 6.3 mm to 38 mm (per ISO 4397). The standard defines design, manufacture, marking, designation and performance verification for metric stud-end hose fittings used with compatible hoses and ports sealed by O‑rings.
Key Topics and Requirements
- Scope and materials: Specifies carbon steel fittings by default; other materials may be agreed between manufacturer and user. Fits hoses sized 6.3–38 mm nominal ID (ISO 4397).
- Metric stud ends and threads: Stud-end threads and port interfaces conform to ISO 6149-2 (heavy-duty S series) or ISO 6149-3 (light-duty L series) and ISO 261 metric thread forms.
- Performance and testing:
- Hose assemblies tested per ISO 6605 (no leakage/failure).
- Fittings’ working pressure verified per ISO 19879.
- Working pressure of an assembly = lower of pressures specified in ISO 6149 series or the hose specification.
- Dimensions and tolerances:
- Detailed dimensional tables and figures for straight and 90° elbow stud fittings.
- Hex across-flat tolerances per ISO 4759-1 (product grade C).
- Surface roughness (Ramax) for machined surfaces = 6.3 µm unless otherwise specified.
- Finish and corrosion resistance:
- Carbon-steel parts require plating/coating that passes a 72 h neutral salt spray test (ISO 9227), with defined exceptions for wear zones.
- Designation and marking:
- Standardized alphanumeric designation format (example: Hose fitting ISO 12151-4 - SDE - LM18 × 12,5).
- Fittings must be permanently marked with manufacturer name/trademark.
- Assembly guidance:
- Annex A contains practical instructions for assembling fittings into ISO 6149-1 straight thread O‑ring ports (O‑ring handling, lubrication and protective caps).
Applications and Who Uses It
- Hydraulic system designers and OEMs specifying reliable hose-to-port connections in industrial and mobile hydraulic systems.
- Manufacturers of hose fittings and hose assemblies for ensuring dimensional interchangeability and test compliance.
- Quality, testing and procurement teams that require standardized designation, corrosion resistance and documented verification testing.
- Maintenance and assembly technicians using Annex A assembly guidance for O‑ring port connections.
Practical uses include hydraulic power units, industrial machinery, mobile equipment, and general-pressure hose installations where metric stud-end O‑ring sealing is required.
Related Standards
Keywords: ISO 12151-4:2007, hose fittings, ISO 6149, metric stud ends, hydraulic fluid power, hose assemblies, ISO 4397, ISO 6605, ISO 19879.
Open preview (PDF)Connections for hydraulic fluid power and general use — Hose fittings — Part 4: Hose fittings with ISO 6149 metric stud ends