DIN 765:2024-09

This document is intended to replace the DIN 765:1955-03 standard withdrawn in August 1981. DIN 766:1954-07 contained a large number of chain types, such as tested, calibrated and tested, non-calibrated round steel chains of grades 2 and 3, as well as untested so-called commercial chains. This diversity within a single standard had repeatedly led to confusion in the past. The task for the future was therefore to prepare separate chain standards. The first step in this direction was taken in 1975, when an attempt was made to transfer the close-tolerance (then referred to as calibrated) round steel chains of grade 3 (then referred to as tempered) to E DIN 765:1975-04. This led to enormous protests from the companies affected in the NRK, as they could no longer market their products using the globally recognized DIN 766 standard number. This first attempt to separate the different types of chains therefore failed. These round steel chains subsequently remained in DIN 766:1986-01. Over the next few decades, the NRK focused once again on revising DIN 766:1954-07. Over time, this work led to the new standard numbers DIN 5685-3, DIN 5698-1, DIN 32891, and DIN EN 14330, in addition to the traditional standard number DIN 766. According to the current state of standardization, only closely tolerated tempered round steel chains of grade 3 for chain conveyors remain in DIN 766. The current project is therefore the revision of DIN 766:1986-01 for closely tolerated round steel chains of grade 3, but only for general purposes, as the use of round steel chains according to DIN 766:1986-01 as hoisting chains is no longer permitted under European standards. Due to the specifications in DIN EN 13157, hoist chains in accordance with DIN EN 818-7, grade T (type T) made of stainless steels shall now be used in manually operated hoists. Due to national regulations, it is recommended that steels for welded round steel chains and individual chain parts in accordance with DIN 17115 be used. For motor-driven hoists in accordance with DIN EN 14492-1 and DIN EN 14492-2, hoist chains made of stainless steel in accordance with DIN EN 818-7, quality class T (type T, DAT, and DT) shall be used. The application of the national standard DIN 17115 is also recommended for type T. This document thus marks the resumption of the project launched in 1975 to phase out close-tolerance (calibrated) round steel chains of grade 3 (then referred to as tempered) and its completion with this publication. This document applies to short-link, tested, close-tolerance round steel chains of grade 4, made of tempered quality steel and in bright or hot-dip galvanized versions, with a range for the nominal diameter, d, from 4 mm to 42 mm and an operating force (WF) from 2,5 kN to 280 kN, as well as for a permissible operating temperature from -20 °C to +550 °C. It specifies their dimensions and mechanical properties. Round steel chains in accordance with this document are used for general purposes throughout the field of technology. This document has been prepared by Working Committee NA 085-00-02 AA "Rundstahlketten, Einzelteile und Zubehör für allgemeine Zwecke" ("Round steel link chains, components and accessories for general purposes") at DIN Standards Committee Round Steel Link Chains (NRK).