EN ISO 6149-4:2017 PDF

Overview

EN ISO 6149-4:2017 specifies the dimensions, design, test methods and performance requirements for external hex and internal hex port plugs intended for use with ISO 6149‑1 ports in fluid power and general applications. The document covers metric screw threads per ISO 261 with O‑ring sealing, and is intended for components used at working pressures up to 63 MPa (630 bar) (permissible pressure depends on size, materials and application). The standard also includes important safety guidance about intermixing types of ports and stud ends.

Key topics and technical requirements

• Port plug types: external hex (hexagon head) and internal hex (Allen) port plugs designed to fit ISO 6149‑1 ports.
• Threads: metric screw threads conforming to ISO 261, tolerance class 6g.
• Dimensions & tolerances: plug dimensions shown in figures/tables of the standard; hex tolerances referenced to ISO 4759‑1 (external hex product grade C, internal hex product grade A). Minimum geometric relationships include across-corner and side-flat proportions. External hex corners are chamfered 10°–30°.
• Sealing: plugs may use elastomeric O‑rings (referenced quality and acceptance criteria such as ISO 3601‑3).
• Performance & testing: specifies working pressure/temperature suitability (typical range −40 °C to +120 °C). Conformance to dimensions alone does not guarantee rated performance-manufacturers must perform the tests described in the standard to verify performance.
• Safety warning: mixing stud ends or ports conforming to ISO 6149‑4 with ports from ISO 1179, ISO 9974, ISO 11926 can create hazardous situations.

Applications and who uses this standard

• Hydraulic and fluid power system designers and OEMs specifying threaded port plugs for manifolds, valves, pumps, reservoirs and general hydraulic equipment.
• Manufacturers and quality engineers producing or testing external hex/internal hex port plugs to ensure dimensional and performance compliance.
• Procurement/specification engineers and test laboratories validating working pressure, temperature and sealing performance.
• Maintenance teams and safety officers assessing compatibility risks when replacing plugs or interfacing different port standards.

Related standards

• ISO 6149‑1 (ports with truncated housing for O‑ring seal)
• ISO 6149‑2 (stud ends)
• ISO 261 (metric screw threads)
• ISO 3601‑3 (O‑ring acceptance)
• ISO 4759‑1 (fastener tolerances)
• ISO 19879, ISO 9227 and others referenced for test methods and coatings

EN ISO 6149-4:2017 is essential when specifying or supplying metric, O‑ring sealed port plugs for high-pressure hydraulic systems-use it to ensure dimensional interchangeability, tested performance and safer component selection.