ISO 965-4:2021 pdf download – ISO general purpose metric screw threads — Tolerances — Part 4: Limits of sizes for hot-dip galvanized external screw threads to mate with internal screw threads tapped with tolerance position H or G after galvanizing.
1 Scope This document specifies limit deviations and limits of sizes for the pitch and crest diameters of the hot- dip galvanized metric external screw threads conforming to the coarse thread series of ISO 262 (from M8 to M64) having a basic profile according to ISO 68-1. This document is applicable to the hot-dip galvanized metric external screw threads to mate with the internal screw threads tapped with tolerance position H or G after galvanizing.
2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 965-1, ISO general purpose metric screw threads — Tolerances — Part 1: Principles and basic data ISO 965-5, ISO general purpose metric screw threads — Tolerances — Part 5: Limits of sizes for internal screw threads to mate with hot-dip galvanized external screw threads with maximum size of tolerance position h before galvanizing ISO 5408, Screw threads — Vocabulary
3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 5408 apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://www.iso .org/obp — IEC Electropedia: available at https://www.electropedia .org/
4 General After the hot-dip galvanization the external threaded products with the tolerance class 6az shall be centrifuged immediately. Products made with thread tolerances in accordance with this document may show lower ultimate tensile loads than the full loadability specified in ISO 898-1 due to reduction of the stress area. External screw threads with thread tolerances according to this document shall not be mated with internal screw threads with thread tolerances in accordance with ISO 965-5 because such combinations will create severe risk for thread stripping.
5 Designation The complete designation of metric screw threads shall be done according to ISO 965-1. The tolerance class designation for external screw threads, ISO 965-4, is 6az. EXAMPLE M12 – 6az
7 Limits of sizes – External screw threads – Coarse thread series Tolerance quality: medium Thread engagement group: normal Tolerance class: 6az The limits of sizes for external screw threads are specified in Table 2. The actual root contour shall not at any point transgress the basic profile and fundamental deviation.
For hot-dip galvanized screw threads, the tolerances apply to the parts before galvanizing. After galvanizing, the actual thread profile shall not at any point transgress the maximum material limits for tolerance position h and are intended to mate with internal screw threads of tolerance position H or G only. NOTE See Annex A for the external screw thread minor diameter, d 3 , used by ISO/TC 2 to calculate the nominal stress area, A s,nom .
