ISO 15330 pdf download.Fasteners — Preloading test for the detection of hydrogen embrittlement — Parallel bearing surface method
1 Scope
This International Standard specifies a preloading test which is able to detect the occurence of hydrogen embrittlement of fasteners at room temperature. This test is applicable to – metric bolts, screws and studs; – thread rolling screws; – self-tapping screws; – self-drilling screws; – nuts; – washers which are made of steel and are under tensile stress. The test shall be carried out within a temperature range of 1 0 ∞C to 35 ∞C. The test is suitable only for in-process control and may be carried out after any step of the manufacturing process. It is not intended as an acceptance test. It is capable of assessing differences or changes in processing conditions or techniques and to determine the effectiveness of the various processing steps including pre- and post-coating treatments (baking) to reduce the mobile hydrogen in the fasteners. This test does not relieve the manufacturer or processor from the responsibility of imposing and monitoring suitable process control. NOTE The chance of detecting hydrogen embrittlement decreases significantly if the test is started more than 24 h after the last step of manufacturing process. Therefore, in normal cases this test is not suitable for acceptance testing. Special attention shall be given to the reference test in clause 7.3.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 273:1 979, Fasteners — Clearance holes for bolts and screws. ISO 2702:1 992, Heat-treated steel tapping screws — Mechanical properties.
3 Terms and definitions
For the purposes of this International Standard the following terms and definitions apply. 3.1 susceptibility to hydrogen embrittlement characteristic of a steel fastener to display brittle failure due to the presence of mobile hydrogen and when subjected to a significant degree of tensile stress and/or adverse service conditions NOTE 1 With increasing susceptibility to hydrogen embrittlement, the critical amount of mobile hydrogen which may cause brittle failure decreases markedly. NOTE 2 After the manufacturing process, susceptibility to hydrogen embrittlement cannot be reduced or changed into an unsusceptible condition, even by any post-coating heat treatment (baking). 3.2 risk of hydrogen embrittlement risk of failure which arises if fasteners made from steel which are susceptible to hydrogen embrittlement absorb hydrogen and are subjected to tensile stress and/or residual tensile stress NOTE The risk of hydrogen embrittlement can be reduced when in the relevant process steps hydrogen supply is minimized and/or when suitable post-coating heat treatment is carried out to enable hydrogen to effuse and/or to trap hydrogen irreversibly in the steel. 3.3 manufacturing lot quantity of fasteners of a single designation including product grade, property class and size, manufactured from bar, wire, rod or flat product from a single cast, processed through the same or similar steps at the same time or over a continuous time period through the same heat treatment and/or coating process, if any Same heat treatment or coating process means: – for a continuous process, the same treatment cycle without any setting modification; – for a discontinuous process, the same treatment cycle for identical consecutive loads (batches). NOTE The manufacturing lot may be split into a number of manufacturing batches for processing purposes and then reassembled into the same manufacturing lot.