4.5.1
Fastener lots shall have receiving inspection and testing performed by an entity whose quality management system is in compliance with, or registered to, an appropriate ISO or equivalent standard (e.g., ISO 17025:2017, General Requirements for the Competence of Testing and Calibration Laboratories, ISO 9001:2015, AS9100D, etc.).
4.5.2
Fastener lots shall be verified by inspection and tests as required in this section and summarized in Table 1. When these inspections and tests are performed on a sampling basis, the required sampling size (A, B, or C) is identified in Table 1 and the corresponding sampling quantity is called out in Table 2. Note: These inspections/tests are performed upon receipt of the fasteners and is in addition to those performed by the fastener manufacturer. Their purpose is to verify the quality of the fastener lot and the integrity of the delivered documentation.
4.5.3
Fastener lot acceptance criteria for inspections and tests shall be zero failures.
4.5.4 Dimensional Inspection
4.5.4.1
All Level I threaded fasteners shall be inspected in accordance with the System 22 criteria of ASME B1.3− 2007, Screw Thread Gaging Systems for Acceptability: Inch and Metric Screw Threads (UN, UNR, UNJ, M, and MJ).
4.5.4.2
Level II and III threaded fasteners shall have dimensional inspection performed on a sampling basis in accordance with the System 21 or 22 criteria of ASME B1.3-2007.
4.5.5 Visual Inspection for Finish
4.5.5.1
Visual inspection for finish (e.g. dry film lubricant, plating) shall be performed on a sampling basis on level I, II, and III fasteners in accordance with the applicable specification. The applicable finish specification will include inspection requirements such as magnification, environment and inspection criteria.
4.5.6 Visual Inspection for Lot Uniformity
Visual inspection shall be performed on all level I, II, and III fasteners at 1X magnification, verifying the fasteners are uniform in appearance, and free from rust, scale, seams, bursts, voids, nicks, gouges, and burrs.
4.5.7 Chemical Analysis
4.5.7.1
Chemical analysis shall be performed on a sampling basis for level II fasteners that have been procured from a nonqualified supplier or have incomplete traceability.
4.5.7.2
For the case of level II fasteners that are procured through a nonqualified supplier and do not have complete traceability, chemical analysis shall be performed using a quantitative technique that allows comparison to the composition ranges specified in the controlling material specification. (reference Table 1, footnote 3)
Note: Chemical analysis is used to verify the integrity of the fastener lot and delivered documentation when procuring through a nonqualified supplier or to provide material identification when the traceability paperwork is incomplete. Level I fasteners require qualified suppliers and complete traceability, additional chemical analysis is not required. Chemical analysis is not required for level III fasteners.
Note: Optical Emission Spectroscopy (OES) is the preferred test method for quantitative elemental analysis. Semi-quantitative methods include X-ray Fluorescence (XRF) and
Energy Dispersive Spectroscopy (EDS), and may be used to verify the correct alloy but do not provide a sufficient level of accuracy to satisfy this requirement.
4.5.8 Tensile Testing
4.5.8.1
Tensile testing shall be performed on a sampling basis for level II threaded fasteners such as bolts, screws, nuts, and nut plates that have been procured from a nonqualified suppliers or have incomplete traceability.
4.5.8.2
Tensile testing shall be performed in accordance with one of the following standards:
- a. NASM1312-8, Fastener Test Methods, Method 8, Tensile Strength − Rev 2
- b. NAM1312-108, Fastener Test Methods, Metric, Method 108, Tensile Strength − Rev 1
- c. ASTM F606/F606M-16, Standard Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
4.5.8.3
Tensile test reports shall identify the location of the tensile break, the ultimate load/strength, and the specification minimum and maximum values.
Note: Load extension curves are not required. Level II fasteners that are smaller than #10 or shorter than 2 times their diameter may need to be procured through a qualified supplier with complete traceability, since tensile testing at receiving inspection may not be possible.