What ships with every kettle

Five documents. The fifth one is the reason the other four matter.

Mill test certificate — EN 10204 Type 3.1Issued by the steel mill and signed by an inspection representative independent of production. Covers heat number, full chemical analysis (C / Si / Mn / P / S / Als), mechanical properties and ultrasonic inspection result. Type 3.2, countersigned by a third party or by your own inspector, is available where your specification requires it — tell us before we place the plate order, because it cannot be added retrospectively without re-sampling.
Welding consumable certificatesIncluding the low-silicon flux used to hold weld metal silicon to specification.
Manufacturing inspection reportsDimensional check against drawing, fit-up records, weld visual inspection, coating thickness.
NDT reportsPlate ultrasonic inspection records and ultrasonic testing of every structural weld, to GB/T 11345-2023 (identical to ISO 17640:2018). Issued in English.
Commissioning heat-up curveThe controlled firing schedule for your first heat, specific to your kettle's dimensions and wall thickness.

Why the heat-up curve is in the package

A kettle that is fired too fast on day one will not reach its design life, no matter how well it was built.

BG/T 1501-2015 Appendix A sets out why. On first firing, the wall has no Fe-Zn alloy layer yet, so the risk of intergranular attack and cracking is at its highest of the kettle’s whole life. At the same time the vessel is releasing manufacturing and welding stress, and the refractory is still giving up moisture.

Commissioning The schedule in BG/T 1501-2015 Appendix A.2.2, plotted to scale. Ambient to 300 °C at 2 °C/h is about six days on its own. The flat section is not slack in the programme — it is where the kettle releases the stress from its own manufacture.

The curve that manages all of that
Stage	Rate or hold
Ambient → 300 °C	≤ 2 °C/h
100 – 120 °C	Hold 6 – 8 h — drives moisture out of new refractory
300 – 330 °C	Hold 24 h — this is where kettle distortion and residual stress release
300 → 420 °C	≤ 5 °C/h
Throughout	Wall inside-to-outside differential < 50 °C; wall-to-base differential < 100 °C

Loading the kettle

Plus the loading rules that go with it: charge with pure zinc ingot above 99.99 %, no lead in the base, ingots stacked tight against the wall because the kettle is side-heated, and a 100 mm gap left in the middle of the stack — zinc expands roughly three times as much as iron, and a tightly packed charge will push on the wall as it heats.

Most of this is not in the sales conversation, and it should be. It is the difference between a kettle that lasts eight years and one that lasts eighteen months. Full commissioning guide →

Marking

Every kettle is marked on both flanks with product name, dimensions, manufacturer, date of manufacture, the standard it was built to, and works serial number (BG/T 1501-2015 §8.1). If you need additional marking for your asset register, tell us before painting.

The tests behind reports 3 and 4 are set out in full on the inspection and test plan, and what we do and do not certify is on standards and compliance.

Source: BG/T 1501-2015 — §6.5, §8.1, Appendix A.2.1–A.2.2. EN 10204 inspection document types.