ISO 9538:2025 pdf download,Aerospace series – Hydraulic tubing joints and fittings – Planar flexure test.
ISO 9538:2025 specifies a planar flexure test procedure for aerospace hydraulic tubing joints and fittings, covering both reconnectable and permanent types. The standard describes how to apply controlled bending (flexure) to the joint/fitting assembly to assess its mechanical durability and structural integrity under bending stresses expected in aircraft hydraulic systems. It is intended for fittings used with high-strength corrosion-resisting hydraulic tubes made of materials such as steel, titanium, and aluminium, including applications relevant to commercial and military aircraft. The document focuses on defining the test setup, the way the specimen is mounted, the loading or bending approach, and the evaluation of results using acceptance criteria. By standardizing the flexure test method and conditions, ISO 9538:2025 helps ensure consistent qualification and comparison of different joint and fitting designs, reducing the risk of premature damage, loosening, or loss of performance after flexing during service.