Breaking Force Testing of Grade 8 Lifting Chain

SCIC·Shanghai Chigong Industrial Co., Ltd.·Lifting Chain Division

Technical Extract

 

What the standard actually requires — and what SCIC verifies on every lot

Clause extract from EN 818-1:1996+A1:2008 and EN 818-2:1996+A1:2008  (DIN EN 818-1:2008-12 / DIN EN 818-2:2008-12)
Rev. 1  ·  October 2026
Medium tolerance  ·  Grade 8

 

Question 1  —  Test Method

The link is pulled until it breaks — never stopped at the minimum.

  • Breaking force is a destructive result by definition: “maximum force which the chain withstands during the course of a static tensile test to destruction”.
  • The force/extension diagram is recorded throughout, and total ultimate elongation is read at fracture — so the test cannot terminate at a target load.
  • Pass requires the recorded peak ≥ Table 5 minimum and elongation ≥ 20 %. A failing sample is re-tested on two further samples.
EN 818-1 §3.7 · §6.5.3 · §6.5.4 · §6.7 · §6.8EN 818-2 §5.4.2 · §6.3.3
Question 2  —  Rate of Loading

A controlled force rate: 10 N/mm²/s, evenly applied.

  • “The rate of loading shall be evenly applied (e.g. at a rate of 10 N/mm²/s).” The reference is stress on the nominal link section — not crosshead travel.
  • No mm/min value exists in EN 818-1 or -2, by design: the mm/min equivalent depends on each machine’s stiffness and jaw seating, so it must be established by a calibration run.
  • Practical cross-check: at 10 N/mm²/s the minimum breaking force is reached in ≈ 80 s for every size from 4 to 45 mm — much faster means the rate is too high.
EN 818-1 §6.5.3 · Annex A (machine, class 1)EN 818-2 §6.3.1

 

Table 5 extract — forces and the equivalent machine setting

d (mm) WLL
(t)		 MPF
(kN)		 BF min
(kN)		 Load rate
(kN/min)		 Elong. A
(min %)
6 1.12 28.3 45.2 33.9 20
8 2 50.3 80.4 60.3 20
10 3.15 78.5 126 94.2 20
13 5.3 133 212 159 20
16 8 201 322 241 20
18 10 254 407 305 20
20 12.5 314 503 377 20
22 15 380 608 456 20
26 21.2 531 849 637 20
32 31.5 804 1290 965 20
36 40 1020 1630 1222 20
45 63 1590 2540 1909 20

Load rate = 10 N/mm²/s × nominal link area (2 × πd²/4), converted to kN/min for machine setting. Highlighted row: d13 — 212 kN minimum reached in ≈ 80 s at 159 kN/min.

 

 

SCIC quality control & assurance — applied to every lifting chain we supply

Sampling: 200 m lots  ·  3 / 2 / 1 destructive samples by size
EN 818-1 Table 2  ·  EN 818-2 §6.2

1Steel & heat traceability

Cast and check analysis verified against EN 818-2 Table 4 — S ≤ 0.025 / 0.030 %, P ≤ 0.025 / 0.030 %. Heat number retained through to the finished lot.

2Heat treatment verified

Full hardening from above AC3, tempered ≥ 400 °C (≥ 1 h equivalent). Effectiveness confirmed by the re-heat test — samples re-heated 1 h at 400 °C must still pass BF and bend.

3100 % proof loading

Every metre proof-loaded to Table 5 MPF, then inspected link by link under proper lighting; faulty links cut out and replaced. Proof force re-applied after acid cleaning or plating.

4Destructive testing per lot

Samples drawn at random per 200 m lot and pulled to fracture at 10 N/mm²/s on a class-1 machine. Peak force and elongation recorded on the force/extension diagram and retained.

5Bend & dimensional checks

Single-link bend test to Table 5 minimum deflection, then examined for cracks and defects. Material diameter measured clear of the weld and away from flattening; pitch within tolerance.

6Marking & documentation

Grade “8” and manufacturer mark at every 20th link or 1 m. Inspection certificate to EN 10204 type 3.1 as standard, type 3.2 on request; records traceable to lot and heat.

 

 

 

Clause index — EN 818-1: §3.7 breaking force · §3.9 total ultimate elongation · §5.3.1 MPF · §5.3.2 BF and A · §5.3.3 bend · §6.2–6.4 sampling · §6.5 static tensile test · §6.5.3 procedure and rate · §6.5.4 elongation · §6.7 acceptance · §6.8 re-tests · Annex A machine · Annex B bend equipment.   EN 818-2: §5.3.1 material · §5.3.2 heat treatment · §5.4.1–5.4.3 mechanical properties · §6.2 lot and samples · §6.3.1–6.3.3 testing and acceptance · §6.4 bend · §7 marking · Table 4 S/P · Table 5 WLL, MPF, BF, bend.

Prepared by SCIC for client training and reference. This is an extract, not a substitute: the complete current editions of EN 818-1 and EN 818-2 govern in all cases, together with the applicable national adoption and any contractual specification. Values shown are for medium tolerance Grade 8 chain (EN 818-2). Questions on a specific order — contact your SCIC account manager.