ASTM F519 hydrogen embrittlement of steel in the coating process
The ASTM F519 standard describes a mechanical test method (tensile or flexure load) and defines acceptance criteria for coating and plating processes that can cause hydrogen embrittlement in steels. Subsequent exposure to chemicals encountered in service environments that come in contact with the plated/coated or bare surface of the steel can also be evaluated.
Test principle Specimen types Testing software requirements Interpretation of test results Suitable testing systems Interesting customer projects
Test principle to ASTM F519
To evaluate hydrogen embrittlement according to ASTM F519, a minimum of 14 specimens from the same batch are required. The first ten specimens are used for tensile testing according to ASTM E8 to determine the notched fracture strength (NFS). Acceptance criterion for this test is that the notched fracture strength (NFS) of each specimen must be within 10 ksi (69 N/mm²) of the mean value. After that, multiple notched specimens from the same batch (min. 4) are simultaneously tested in a 200-hour sustained load test (SLT).
For testing of coating and plating processes, the specimens must sustain the load for 200 hours. The specimens are installed in series by means of intermediate adapters, thus all specimens experience the same load (75% of the NFS). Multiple batches can be tested at the same time if the notched fracture strength of the batches is within ±1%.
Types of specimens
The following specimen types are used for the evaluation of hydrogen embrittlement to ASTM F519:
Type 1: notched specimens
- Type 1a: notched, round, tensile load
- Type 1a.1: standard size
- Type 1a. 2: oversized - Type 1b: notched, round, tension, self loading fixture
- Type 1c: notched, round, bend, self loading fixture
- Type 1d: notched, C-Ring, bend, self loading fixture
- Type 1e: notched, square, bend
Type 2: unnotched specimens
- Type 2a: O-Ring, bend, self loading fixture
Testing software requirements
The special ASTM F519 requirements are met with our testXpert testing software:
- Test interruptions due to specimen breakage with automatic recalculation of the test duration are detected.
- Multiple specimens from different batches (max. 4 batches of 4 specimens each) are tested simultaneously and evaluated individually per batch.
- Easy and intuitive operation when performing the test and the automatic evaluation of tamper-proof test results.
- testXpert provides the option to perform the initial tensile test to determine the notched fracture strength (NFS) and automatically assume the NFS value for the hydrogen embrittlement evaluation.
Interpretation of the test results
- None of the four specimens break:
the plating/coating process is evaluated as non-brittle. - One of four specimens breaks:
if only one of a min. of four specimens breaks within the 200 hours, the broken specimen is removed from the load string and replaced by an unnotched dummy specimen. The three remaining specimens are then further loaded. After completion of the 200 hours of loading, additional loading to 90% NFS is performed for two hours at a time in 5% increments. If the three remaining specimens withstand 90% NFS for two hours, the plating/coating process is considered non-embrittling. - Two or more specimens break:
if two or more specimens break within the 200 hours of testing, the plating/coating process is considered embrittling.
