ISO 4042 pdf download.Fasteners — Electroplated coatings
1 Scope
This International Standard specifies dimensional requirements for electroplated fasteners of steel or copper alloy. It specifies coating thicknesses and gives recommendations for hydrogen embrittlement relief for fasteners with high tensile strength or hardness and for surface-hardened fasteners. This International Standard primarily concerns the electroplating of threaded fasteners, but it may also be applied to other threaded parts. For the applicability to screws that cut or form their own mating threads, see clause 8. The specifications given in this International Standard may also be applied to non-threaded parts such as washers and pins.
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 965-1 :1 999, ISO general purpose metric screw threads — Tolerances — Part 1 : Principles and basic data. ISO 965-2:1 999, ISO general purpose metric screw threads — Tolerances — Part 2: Limits of sizes for general purpose bolt and nut threads — Medium quality . ISO 965-3:1 999, ISO general purpose metric screw threads — Tolerances — Part 3: Deviations for constructional threads . ISO 1 456:1 988, Metallic coatings — Electrodeposited coatings of nickel plus chromium and of copper plus nickel plus chromium. ISO 1 458:1 988, Metallic coating — Electrodeposited coatings of nickel . ISO 1 502:1 996, ISO general purpose metric screw threads — Gauges and gauging .
3 Terms and definitions
For the purposes of this International Standard, the definitions given in ISO 2064 (in particular, the definitions of significant surface, measuring area, local thickness and minimum local thickness) and ISO 3269 together with the following, apply. 3.1 batch quantity of identical fasteners from the same manufacturing lot processed together at one time 3.2 production run those batches of parts processed continuously without any changes in coating techniques or constituents 3.3 batch average thickness calculated average thickness of a coating if it was uniformly distributed over the surface of the parts of the batch 3.4 baking process of heating parts for a definite time at a given temperature in order to minimize the risk of hydrogen embrittlement 3.5 baking duration time at which the parts are held at the specified temperature which they shall have completely reached
4 Dimensional requirements and gauging
4.1 Dimensional requirements before electroplating Before coating, parts shall comply with the relevant International Standards if applicable or other standards as specified, except where threads or other features are specifically manufactured to allow, for functional reasons, the application of thicker coatings than are possible on normal threads. Coating thicknesses which can be applied on ISO metric threads in accordance with ISO 965-1 , ISO 965-2 and ISO 965-3 depend on the fundamental deviation available, which itself depends on the screw thread and the following tolerance positions:  g, f, e for external threads;  G for internal threads or H if required. The tolerance positions apply prior to application of the electroplated coating. 4.2 Dimensional requirements after electroplating After coating, ISO metric screw threads shall be gauged in accordance with ISO 1 502 with a GO gauge of tolerance position h for external threads and H for internal threads. Other product dimensions apply only before coating. NOTE Care should be exercised where relatively thick coatings may affect dimensions with small tolerances as in the case of internal drives; in these cases an agreement should be made between the supplier and the purchaser. The applicability of the recommended coatings to ISO metric threads is limited by the fundamental deviation of the threads concerned and hence, by the pitch and tolerance positions. The coating shall not cause the zero line (basic size) to be exceeded in the case of external threads, nor shall it fall below this line in the case of internal threads. This means that for an internal thread of tolerance position H, a measurable coating thickness can only be applied to the threads if the tolerance zone is not taken up to the zero line (basic size).