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Breaking Force Testing of Grade 8 Lifting Chain

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

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.