BS ISO 4778:2019 pdf download – Round steel short link chains for lifting purposes — Chain slings of welded construction — Grade 8 After proof loading, the difference between the longest and shortest chain legs of a multi-leg chain sling,when measured under a tension of 20 % of the working load limit, shall not exceed 10 mm for chain legs up to 2 m in length. For chain slings in excess of 2 m, the difference between the longest and shortest chain legs may be increased by 5 mm/m. 4.2 Components 4.2.1 Chain legs Chain legs shall comply with ISO 3076. 4.2.2 Master links Master links shall comply with ISO 16798. The inside dimension and the cross-section of the material shall be such that: a) the master link fits to a shank hook (e.g. according to ISO 17440; see Annex C); b) the inside width of the master link is not less than 1,2 times the maximum width (see dimension b 2 in ISO 17440:2014, Figure A.1 and Table A.1) of the shank hook; c) for chain slings with hooks as lower terminal components the inside dimensions and the crosssection are such as to allow the lower terminal component when not loaded to be hooked back into the master link while it is on the shank hook. Master links may be of round or other suitable cross-section. But the cross-section of the material shall be chosen so that: a) after proof loading (see 4.4.1) the master link does not show any significant permanent deformation; b) the minimum total ultimate elongation at fracture is at least that of the sling chain. NOTE A method of calculating the cross-section of master links is given in Annex D. IMPORTANT — Egg- or pear-shaped links shall be designed to exclude unintended inverting. 4.2.3 Intermediate master links, joining links and end links Intermediate master links, joining links and end links shall comply with ISO 16798 except for the clauses relating to link dimensions. The internal dimensions of intermediate master links, joining links and end links shall be such that they ensure free articulation of the links. The cross-section of the material shall be such that: a) after proof loading (see 4.4.1) the intermediate master links, joining links and end links do not show any significant permanent deformation; b) the minimum total ultimate elongation at fracture is at least that of the sling chain. IMPORTANT —...
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