Significance and Use
5.1 Plating/coating Processes—This test method provides a means by which to detect possible hydrogen embrittlement of steel parts during manufacture by verifying strict controls during production operations such as surface preparation, pretreatments, and plating/coating. It is also intended to be used as a qualification test for new plating/coating processes and as a periodic inspection audit for the control of a plating/coating process.
5.2 Service Environment—This test method provides a means by which to detect possible hydrogen embrittlement of steel parts (plated/coated or bare) due to contact with chemicals during manufacturing, overhaul and service life. The details of testing in a service environment are found in Annex A5.
Scope
1.1 This test method describes mechanical test methods and defines acceptance criteria for coating and plating processes that can cause hydrogen embrittlement in steels. Subsequent exposure to chemicals encountered in service environments, such as fluids, cleaning treatments or maintenance chemicals that come in contact with the plated/coated or bare surface of the steel, can also be evaluated.
1.2 This test method is not intended to measure the relative susceptibility of different steels. The relative susceptibility of different materials to hydrogen embrittlement may be determined in accordance with Test Method F1459 and Test Method F1624.
1.3 This test method specifies the use of air melted AISI E4340 steel per SAE AMS-S-5000 (formerly MIL-S-5000) heat treated to 260 to 280 ksi (pounds per square inch ×1000) as the baseline. This combination of alloy and heat treat level has been used for many years and a large database has been accumulated in the aerospace industry on its specific response to exposure to a wide variety of maintenance chemicals, or electroplated coatings, or both. Components with ultimate strengths higher than 260 to 280 ksi may not be represented by the baseline. In such cases, the cognizant engineering authority shall determine the need for manufacturing specimens from the specific material and heat treat condition of the component. Deviations from the baseline shall be reported as required by 12.1.2. The sensitivity to hydrogen embrittlement shall be demonstrated for each lot of specimens as specified in 9.5.
1.4 Test procedures and acceptance requirements are specified for seven specimens of different sizes, geometries, and loading configurations.
1.5 Pass/Fail Requirements—For plating/coating processes, specimens must meet or exceed 200 h using a sustained load test (SLT) at the levels shown in Table 3.
| Type | Item | Sampling of | Requirement/Method |
| 1 | Tensile Strength | 4 each | Test Method E8. Tensile strength of each specimen must be within 10 ksi of the average. |
| 1  | HardnessA | 5 % | 51 to 53 HRC per Test Methods E18. |
| 1  | Dimensions | 100 % | Meet tolerances of |
| 1  | Notched Fracture Strength (NFS) | 10 ea | Test Methods E8/E8M. NFS of each specimen |
| 1c | Self-loading | 10 ea | Alternate: The number of |
| 1d | Self-loading | 10 ea | Alternate: The change in |
| Item | Treatment A | Treatment B | |
| Bath composition: | Range | Optimum |
|
|  Cadmium (as CdO) | 2.9 to 5.5 oz/gal (22 to 41 g/L) | 4.5 oz/gal (33.7 g/L) | same as Treatment A |
|  Total Sodium cyanide | 12.0 to 16.0 oz/gal (89.9 to 120 g/L) | 14 oz/gal (104 g/L) | same as Treatment A |
|  Ratio NaCN to CdO | 2.8/1 to 6.0/1 | 3.0/1 | same as Treatment A |
|  pH | 12.0 or greater | 12.0 | same as Treatment A |
|  Temperature | 70–90°F (21–32°C) | 75°F (24°C) | same as Treatment A |
|  Sodium hydroxide | 1.0 to 3.2 oz/gal (7.5 to 24.0 g/L) | 2.5 oz/gal (18.7 g/L) | same as Treatment A |
|  Brightener such as | Manufacturer's suggested range | None | |
|  Electroplating current | 10 A/ft2  (108 A/m2) | 60 A/ft2  (645 A/m 2) | |
|  Electroplating time | 30 minutes | 6 minutes | |
| Baking |
|
|
|
|  Baking temperature | 375 ± 25°F (190 ± 14°C) | same as Treatment A | |
|  Baking time: Type 1 | Do Not Bake | 23 h | |
|  Baking time: Type 2a | 8 h | 23 h | |
| Chromate TreatmentC | Yes | same as Treatment A | |
| Type 1a, 1b, 1c, 1d, 1e | 75 % of the tensile or bend NFS (Table 1). |
| Type 2a | 92 % of the Test Methods E8/E8M, E4 ultimate strength, obtained by deflecting a 2.300-inch diameter O-Ring specimen with a 2.525-inch stressing bar. |
1.5.1 The loading conditions and pass/fail requirements for service environments are specified in Annex A5.
1.5.2 If approved by the cognizant engineering authority, a quantitative, accelerated (≤ 24 h) incremental step-load (ISL) test as defined in Annex A3 may be used as an alternative to SLT.
1.6 This test method is divided into two parts. The first part gives general information concerning requirements for hydrogen embrittlement testing. The second is composed of annexes that give specific requirements for the various loading and specimen configurations covered by this test method (see section 9.1 for a list of types) and the details for testing service environments.
