Hydrogen embrittlement is the change in brittleness of metals due to hydrogen penetrating and being absorbed into the metal crystal lattice. Hydrogen absorption can occur during the manufacturing process or during surface treatment, e.g. during galvanic zinc plating of the component. Components consisting of high-strength steels with a high martensite content, as are used both in the automotive and aircraft industries, are especially susceptible to damage due to hydrogen embrittlement. Fokker Landing Gears in Helmond (Netherlands)uses creep testing systems from Messphysik in order to minimize this risk.
High-strength steels are used primarily for fasteners, load carrying landing gear component as well as zinc-plated bolts in the automotive and aircraft industries. If the load is high enough, a brittle fracture can occur without any recognizable indications of the imminent failure. Appropriate tests, e.g. according to NADCAP requirements in the aviation industry, are essential in order to handle this potential safety risk.
Fokker Landing Gears recently equipped its mechanical laboratory with three type Kappa 50 LA creep testing machines from Messphysik for this purpose. Hydrogen embrittlement is tested mechanically in accordance with the international ASTM F519 standard using these lever-arm creep testing systems. The required specimens are produced and undergo surface treatment in parallel with the manufacturing process for the original components. Three testing systems, in which four specimens each are tested simultaneously, were installed owing to the number of specimens and the test duration of 200 hours.
Fokker Landing Gears, as a supplier to renowned companies in the aircraft industry, thereby demonstrates that the manufacturing process is under complete control. One of the convincing features of the Messphysik creep testing systems is the flexibility provided by the testControl machine electronics and testXpert testing software. Expert advice and the compact size of the testing systems were also decisive selection criteria.
