Disk Pressure Testing of Hydrogen Environment Embrittlement

Abstract

The rapture appearances and pressures are compared for clamped disks, biaxially stressed to rupture under upward increasing pressures of helium or of an embrittling fluid such as gaseous hydrogen isotopes. Usually the downward surface is available for observation during the test in progress, but it can be exposed to a second embrittling medium. Factors studied include: (a) for the materials; chemistry (aluminum, cobalt, chromium, copper, iron, nickel, platinum, titanium, uranium, zirconium, etc., base), surface condition, thermomechanical processing, welding, etc., (b) for the testing conditions (- 196 to - 450°C), H2 pressure, purity, pressure increase rate, etc. Low-cycle fatigue and delayed failure tests can also be conducted and discontinuous cracking monitored by various techniques, especially permeation. The disk pressure test (DPT) can be used for selection and quality control of bulk materials, protective coatings against hydrogen environment embrittlement (HEE), and their processing. Materials selection is made according to screening tests of increasing severity. The DPT shows evidence of other causes of embrittlement and their synergistic effects with HEE, which is quite important. Other advantages of DPT, such as sensitivity, versatility, rapidity, simplicity of operation and maintenance, safety, low cost of specimens and equipment, etc., are outlined and compared to other methods.

Developments and Design of Novel (Non-Palladium-Based) Metal Membranes for Hydrogen Separation

“…v. high pressure and temperature over an extended period). Electrochemical permeation methods 67,136 have been used to confirm or extend hydrogen embrittlement mechanical tests. , …”

“…While a standard protocol for screening the durability of metal membranes has not been established, various mechanical tests can be used to assess the effect of hydrogen on metal membranes. Such useful tests include the following: delayed failure tests, fracture mechanics, slow strain-rate tensile tests, , Charpy impact tests, , creep rupture tests, stress/strain controlled fatigue tests, , and disk-pressure or disk-burst tests. , The standard test for measuring hydrogen embrittlement in steel is the incremental step loading test, which determines the onset of subcritical crack growth on a tensile or 4 point bend sample after treatment in hydrogen (e.g. through processing such as plating) .…”

“…The disk-burst test is highly relevant to assessing the performance of a metal for a H 2 separation membrane, and test samples can be designed to be interchangeable with the permeation test rigs described previously. Subjecting a membrane to the disk-burst test involves clamping a thin, circular disk along its edge and applying a pressure differential to cause biaxial flexure. , The resulting pressure to failure in hydrogen ( P H2 ) is compared with that of an identical sample subjected to He ( P He ) for a specific temperature. The ratio of these pressures is indicative of the susceptibility ( S H2 ) of the material to hydrogen degradation (i.e.…”

Developing Fatigue Pre-crack Procedure to Evaluate Fracture Toughness of Pipeline Steels Using Spiral Notch Torsion Test

“…A variety of testing methods [ASTM 2010, Carlisle 1959, Gaydos 2007 have been proposed for mechanical testing for steels affected by hydrogen embrittlement , including tensile test [Caskey 1983], notched tensile test [Walter 1969, ASTM 2010 [Fidelle 1974], constant displacement stress bar test [ASTM 2010], and torque bolt test [Carlisle 1959]. However, there has been little effort devoted to developing a test to characterize the fracture behavior of steel under mixed loading modes, particularly mode I and mode III, which is essential for design and development of these materials for hydrogen infrastructures.…”

The TITAN reversed-field-pinch fusion reactor study

“…Hydrogen embrittlement has been observed in ferrous alloys over a wicle range of temperatures, -100 to +700 °C. However, the most severe embrittlemeut in steels occurs around room temperature [96][97][98][99]. The temperature dependence of the tensile strength of a high-strength steel is shown in Figure 16.2-27.…”