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WLL 450T Polyester Round Slings
A WLL 450T polyester round sling is rated 450,000 kg on a single vertical leg, with a minimum breaking load of 3,150,000 kg at 7:1 and a proof load of 900,000 kg. Continuous high-tenacity polyester core, heavy duty woven sleeve, no metal in the load path.
Nothing at this size is bought off a shelf. A 450 t sling exists because one lift needed it, and the useful question for a buyer is not what the article is — the figure above answers that — but how it gets approved, built and released. That is what this page covers.
Where the 450 Tonne Size Comes From
It usually comes out of the arithmetic of one lift. A 900 t module on four legs at 30° asks for about 429 t per leg once the 2.1 assembly factor is applied — 95% of a 450 t rating. A 400 tonne sling is short of that; a 500 tonne sling covers it with capacity the lift does not use. That gap is the reason this size is ordered.
| Arrangement | Mode factor | Working load limit |
|---|---|---|
| Vertical | 1.0 | 450 t (450,000 kg) |
| Choked | 0.8 | 360 t (360,000 kg) |
| Basket, 0–7° | 2.0 | 900 t (900,000 kg) |
| Basket, 7–45° | 1.4 | 630 t (630,000 kg) |
| Basket, 45–60° | 1.0 | 450 t (450,000 kg) |
Multi-leg assembly factors: 2 legs 1.4 (0–45°) and 1.0 (45–60°); 3 and 4 legs 2.1 (0–45°) and 1.5 (45–60°). O 900 t basket figure is academic on most sites — there are few hooks and fewer beams rated to match it, so the sling is normally the strongest item in the set, not the weakest.
How a 450 Tonne Sling Is Built and Released
Six stages, and the first two decide everything that follows.
| Stage | What is settled | What you receive |
|---|---|---|
| 1. Lift data | Load, centre of gravity, leg count and angle, the hook or shackle the body will sit in. | A sizing proposal, with the working rating in each arrangement. |
| 2. Approval drawing | Length and its convention, sleeve build, eye or endless form, marking layout, set identification. | A drawing to sign — this is the document everything else is checked against. |
| 3. Core build | Yarn lot, end count, continuous loop, no stitch or splice in the load path. | Batch record tying the sling to its yarn lot. |
| 4. Sleeve and closing | Double-layer sleeve, wear pads at the choke point, closing stitch, label position. | In-process check before the body goes to the bed. |
| 5. Proof load | 900,000 kg applied to each sling individually. | A test record against that sling’s serial number. |
| 6. Marking and packing | WLL in kg, effective length, standard, manufacturer, serial or batch. | Coiled body, crate or pallet, certificate pack. |
If a supplier cannot show you stage 2 and stage 5 for the sling you are being offered, the rest of the paperwork is decoration.
What Has to Be Settled Before the Drawing
These six answers are what turn an enquiry into a drawing. Supplying them together usually removes a round of questions:
- Length and its convention. Lay-flat length or full circumference of the loop — the difference is a factor of two, and the sling cannot be shortened later.
- The interface. Bowl and pin size of the hook or bow shackle, so the body bears on a radius rather than a pinch point. A spreader beam changes this answer entirely if the legs would otherwise splay wide.
- Leg count and angle. The rating is per leg; the assembly factor belongs to the configuration.
- Marking and set identification. Whether the slings are one set, and how that set is identified on the label.
- Fibre. Polyester as standard; an aramid version where the load is hot.
- Documents and delivery. Certificate format, packing, and the port the crate ships from.
Technical Specifications
| Product | WLL 450T polyester round sling / 450 tonne round sling / 450,000 kg heavy duty round lifting sling |
|---|---|
| Standard | AS 4497:2018; EN 1492-2 and ISO 4878 on request |
| Working load limit (vertical) | 450,000 kg (450 t) |
| Minimum breaking load | 3,150,000 kg (7 × WLL) |
| Proof load | 900,000 kg (2 × WLL), applied to every sling |
| Safety factor | 7:1 |
| Configuration | Endless loop as standard; two stitched eyes on request |
| Core | High-tenacity polyester parallel yarn, continuous loop |
| Sleeve | Heavy duty woven polyester, double layer; wear pads at the choke point on request |
| Elongation at WLL | Approx. 2–3% |
| Working temperature | −40 °C to +100 °C with a polyester core |
| Effective length | Made to the approval drawing — lay-flat length or full circumference |
| Marking | Sewn label: WLL in kg, effective length, standard, manufacturer, serial or batch |
| Packing | Coiled and strapped, poly-wrapped, labelled crate or pallet for export |
| HS code | 630790 |
Options and OEM
Polyester core as standard; aramid for hot loads and a UHMWPE (Dyneema) core where the weight of the sling itself matters. O eye-and-eye form is available on the same core and sleeve when a defined eye-to-eye length is more useful than an endless loop. Sleeve colour, wear pads, length convention, label layout including set identification, and packing are specified on the drawing.
Frequently Asked Questions
What is the proof load?
900,000 kg, twice the vertical working load limit, applied to each sling and recorded against its serial number.
How much can four 450 t slings lift?
945,000 kg at 0–45° to vertical (factor 2.1), or 675,000 kg at 45–60° (factor 1.5).
Can it be made to a specific length?
Yes — length is set on the approval drawing before production. State whether the figure is lay-flat length or full circumference.
What is needed before the drawing?
Load and centre of gravity, leg count and angle, hook or shackle size, length convention, marking and set ID, and the document format at delivery.
Do you make larger sizes?
Yes — 500 t, built on the same basis, with a 1,000,000 kg proof load.
Request a Quote for a 450 Tonne Sling
Send the six items above — or the lift plan itself — and we will return the sizing, the approval drawing and the proof load record for the sling. lift98@jslift.com · WhatsApp +86 180 6600 2268.